Publications by authors named "Payam Nabovati"

46 Publications

Agreement of Fixation Disparity Curve between Two Different Instruments.

Optom Vis Sci 2021 Jun;98(6):629-635

Department of Basic Sciences, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Significance: Fixation disparity tests with various characteristics of fusional stimulus are very important for assessment of decompensated heterophoria. The results suggest that there was no reasonable agreement between the fixation disparity curve's parameters of the modified near Mallett unit and the Sheedy disparometer.

Purpose: The purpose of this study was to determine the agreement of the fixation disparity curve parameters between the modified near Mallett unit and the Sheedy disparometer in patients with decompensated near heterophoria.

Methods: A total of 147 young adults (mean age, 22.7 ± 4.8 years) participated in this cross-sectional study. After applying the exclusion criteria, the statistical analysis was done on the data of 134 individuals. All participants underwent preliminary optometric examinations including the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, and unilateral and alternating cover tests. The fixation disparity was evaluated using the modified near Mallett unit and the Sheedy disparometer at 40 cm, and forced-vergence fixation disparity curves were generated.

Results: There were statistically significant differences in the fixation disparity curve parameters (except the center of symmetry) between the two devices. The median fixation disparity measured by the Sheedy disparometer was more positive compared with the modified near Mallett unit (toward more esodisparity or less exodisparity). The median associated phoria measured by the Sheedy disparometer was more positive compared with the Mallett unit. Also, the slope of the curve obtained by the Mallett unit was steeper. The wide limits of agreement indicated the poor agreement of all fixation disparity curve parameters between the two instruments.
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http://dx.doi.org/10.1097/OPX.0000000000001708DOI Listing
June 2021

Convergence Insufficiency in the Geriatric Population.

Optom Vis Sci 2021 Jun;98(6):613-619

Department of Ophthalmology, Feiz Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.

Significance: The present study is the first population-based study to examine the prevalence of convergence insufficiency and its associations specifically in the geriatric population. Knowledge of the population-based determination of prevalence of this disorder in the elderly is necessary to support proper clinical diagnosis and management.

Purpose: This study aimed to determine the prevalence of convergence insufficiency and its associated factors in a geriatric population.

Methods: In this study, all residents older than 60 years in Tehran city were selected through random stratified cluster sampling. All participants underwent a complete ocular examination including the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, binocular vision assessments including unilateral and alternating cover tests, measurement of the near point of convergence, the positive fusional vergence, and finally ocular health examination.

Results: In this population-based sample of 1793 participants, the overall prevalences of two-sign and three-sign convergence insufficiency were 29.6% (95% confidence interval, 27.2 to 32.0%) and 21.5% (95% confidence interval, 19.5 to 23.6%), respectively. There were no statistically significant differences in the prevalence of both two-sign (P = .19) and three-sign (P = .41) convergence insufficiency between men and women. The highest and lowest prevalences of two-sign and three-sign convergence insufficiency were in the age groups 70 to 74 and 75 to 79 years, respectively. The prevalence showed no significant trend with age (P = .26 for two-sign convergence insufficiency, P = .33 for three-sign convergence insufficiency). In the multiple logistic regression model, none of the variables, including age, sex, and refractive errors, showed a significant relationship with convergence insufficiency (all, P > .05).

Conclusions: The results of the present study showed a high prevalence of convergence insufficiency in the geriatric population. Clinicians should give special attention to this binocular vision disorder in this age group.
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http://dx.doi.org/10.1097/OPX.0000000000001709DOI Listing
June 2021

Binocular vision disorders in a geriatric population.

Clin Exp Optom 2021 May 20:1-7. Epub 2021 May 20.

Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

A population-based epidemiological survey is important to help establish the frequency of binocular vision disorders in a geriatric population. Such data will be useful to clinicians and help guide diagnostic testing for this age group. To determine the prevalence of binocular vision disorders and their associations with age and sex in the geriatric population. This report is a part of the Tehran Geriatric Eye study (TGES); a population-based cross-sectional study conducted on residents over 60 years of age in Tehran, Iran, using random stratified cluster sampling. A total of 165 clusters were selected (proportionally to size) from 22 strata of Tehran city. All participants underwent a complete ocular examination including the measurement of visual acuity, refraction, unilateral and alternating cover tests, and the Worth 4-dot suppression test. Strabismus was defined as the presence of constant unilateral or alternating esotropia or exotropia at either near (40 cm) or far (6 m). Distance and near exophoria were defined as more than 3 and 9 of exophoria at 6 m and 40 cm, respectively. Distance and near esophoria were defined as more than 1 and any amount of esophoria at 6 m and 40 cm, respectively. Statistical analysis was performed on the data of 2,227 participants. The mean age of the participants was 66.6 ± 5.4 years and 59.4% were female. The prevalence of distance exophoria, esophoria, and hyperphoria was 8.9%, 0.34%, and 0.29%, respectively. The prevalence of near exophoria, esophoria, and hyperphoria was 32.4%, 0.61%, and 0.37%, respectively. The prevalence of distance exotropia and esotropia was 1.3% and 0.63%, respectively. The prevalence of near exotropia and esotropia was 4.6% and 0.59%, respectively. Non-strabismic binocular vision disorders were prevalent in an elderly population. Exo deviations were more prevalent than eso deviations.
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http://dx.doi.org/10.1080/08164622.2021.1922065DOI Listing
May 2021

Corneal asphericity and related factors in the geriatric population: A population-based study.

Ophthalmic Physiol Opt 2021 May 17. Epub 2021 May 17.

Department of Basic Sciences, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Purpose: To determine the distribution of the corneal asphericity coefficient (Q value) and related factors in an Iranian geriatric population.

Methods: This population-based study was conducted in 2019 in Tehran, using stratified multistage random cluster sampling. The study population was ≥60 years of age. Participants underwent corneal imaging using a Pentacam HR. Mean keratometry, corneal astigmatism, central corneal thickness, anterior chamber depth and the overall anterior and posterior Q values (for 8 mm chord diameter) were recorded. Axial length measurements were performed using the IOL Master 500.

Results: 2457 eyes of 2457 individuals were analysed. The mean age was 67.3 ± 5.82 years and 1479 (60.2%) were female. The mean Q value for the anterior corneal surface was -0.35 ± 0.17 (95% CI: -0.35 to -0.34). The anterior Q value showed a statistically significant inverse relationship with axial length and mean keratometry, and a significant direct association with anterior chamber depth and corneal astigmatism. The mean posterior Q value was -0.41 ± 0.15 (95% CI: -0.42 to -0.40). The posterior Q value had a significant direct relationship with age, anterior chamber depth, mean keratometry and corneal astigmatism.

Conclusion: The corneal Q values in this geriatric Iranian population were more negative than the values reported in most previous studies. Corneal asphericity was greater affected by ocular biometry and corneal curvature than demographic factors and refractive status.
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http://dx.doi.org/10.1111/opo.12831DOI Listing
May 2021

To compare on-axis measurements of the axial length with off-axis measurements in the paracentral horizontal and vertical positions.

Semin Ophthalmol 2021 Apr 4:1-4. Epub 2021 Apr 4.

Department of Basic Sciences, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

: To compare on-axis measurements of the axial length (AL) with off-axis measurements in the paracentral horizontal and vertical positions using the Lenstar LS 900 biometer.: In this, the samples were selected from patients scheduled for cataract surgery using a systematic randomization method. After applying the exclusion criteria, all subjects underwent optometric examinations and AL measurement using the Lenstar. Five consecutive, non-cycloplegic measurements were done on the right eye centrally, 10° temporally, 10° nasally, 10° superiorly and 10° inferiorly on the retina by the same examiner.: Two hundred and seven eyes were examined in this study, of which 126 (60%) were for female patients. The mean age of the participants was 64.32 ± 10.77 years (range: 34-91 years). The mean central, superior, inferior, temporal, and nasal axial AL was 23.22 ± 1.02, 23.21 ± 1.02, 23.21 ± 1.02, 23.21 ± 1.02, 23.20 ± 1.03, respectively. Comparison of these readings using repeated measures ANOVA showed a statistically significant difference in the AL value among these positions. According to the post-hoc results, superior and nasal AL was statistically significantly lower compared to the central AL.: If on-axis biometry is not available, AL can be measured in an off-axis manner in the paracentral temporal, superior and inferior positions. Considering the marked difference in AL measurement between central and nasal positions, off-axis measurement is not recommended in the nasal part because it may be associated with a marked hyperopic shift after cataract surgery.
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http://dx.doi.org/10.1080/08820538.2021.1910318DOI Listing
April 2021

Evaluation of the presence of a central fusion lock effect on fixation disparity curve parameters in symptomatic and asymptomatic subjects.

Clin Exp Optom 2021 Mar 22:1-8. Epub 2021 Mar 22.

Department of Medical Surgical Nursing, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

: Several parameters are likely to affect the magnitude of fixation disparity (FD) and FD curve characteristics. Presence of a central fusion lock may have an important effect on clinical testing of FD and interpretation of its results.: The aim of this study was to evaluate FD curve parameters using the modified near Mallett unit (with a central fusion lock) and the Sheedy disparometer (without a central fusion lock) in symptomatic and asymptomatic subjects.: This cross-sectional study was conducted in 147 patients with a mean age of 22.5 years who presented to the optometry clinic of Paramedical College of Mashhad University of Medical Sciences. The symptoms were recorded in a questionnaire for each patient. FD was measured using the modified near Mallett unit and Sheedy disparometer and FD curves were generated using the AutoCAD 2005 software.: There was a significant difference in the FD, associated phoria, and slope measurements between the two devices (all p values < 0.05). Significant difference was found in the mean FD between symptomatic and asymptomatic subjects using the modified near Mallett unit (p < 0.0001) and Sheey disparometer (p = 0.007). In symptomatic subjects, the mean slope was steeper for the modified near Mallett unit compared to the Sheedy disparometer (p = 0.001). Although the mean centre of symmetry was more negative in the modified near Mallett unit versus the Sheedy disparometer, the difference between the instruments was not significant in symptomatic (p = 0.477) and asymptomatic (p = 0.257) participants.: There are differences in the FD curve parameters between the modified near Mallett unit and Sheedy disparometer. Slope is a proper criterion for differentiating asymptomatic subjects from symptomatic individuals. The modified near Mallett unit is a more precise tool for assessment of non-compensated heterophoria compared to the Sheedy disparometer.
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http://dx.doi.org/10.1080/08164622.2021.1878844DOI Listing
March 2021

Predictor factors of prism effectiveness in young adults with convergence insufficiency.

Clin Exp Optom 2021 Feb 27:1-6. Epub 2021 Feb 27.

Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

: The findings of this study can be useful in the process of patient selection as well as in optimising the prescription of the prism in patients with convergence insufficiency.: To determine the relationship between the demographic variables and baseline clinical characteristics with the prism effectiveness in young adults with convergence insufficiency.: Sixty-four young adults with convergence insufficiency entered a randomised clinical trial and were randomly assigned to either treatment or placebo groups. For participants in the treatment group, the near optical correction containing base-in prism was determined based on the Sheard's criterion. Participants in the placebo group received near optical correction. After three months of using the assigned correction, the outcome examinations were performed.: In the univariate analysis, a remote near point of convergence, a higher baseline symptoms score, and a higher prescribed prism power showed a significant relationship with the increase in prism effectiveness. A significant inverse relationship was found between the near positive fusional vergence, vergence facility, and prism adaptation rate with the prism effectiveness. Based on the results of the multiple regression, the prism adaptation rate was the only independent predictor factor of prism effectiveness, so that the prism effectiveness increased by 0.60 for each per cent reduction in prism adaptation rate.: Prism adaptation is the only independent predictive factor of prism effectiveness in young adults with convergence insufficiency. Based on the findings of the present study, it is recommended that careful assessment of prism adaptation be considered before considering prism prescription.
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http://dx.doi.org/10.1080/08164622.2021.1878828DOI Listing
February 2021

The distribution of the near point of convergence and its related factors in an elderly population: the Tehran Geriatric Eye Study (TGES).

Eye (Lond) 2021 Feb 19. Epub 2021 Feb 19.

Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Background: To determine the distribution of the near point of convergence (NPC) and its related factors in an elderly population in Tehran, Iran.

Methods: This population-based cross-sectional study was conducted on the elderly population (60 years of age and over) of Tehran, Iran in 2019. The samples were selected using stratified random cluster sampling. The examinations included the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, unilateral and alternate cover test, ocular health examination, and NPC measurement.

Results: The mean age of the participants was 65.90 ± 4.56 years and 59.6% of them were females. The mean (95% CI) NPC in the total sample was 7.84 cm (95% CI: 7.65-8.03). The mean (95% CI) NPC in males and females was 7.92 cm (7.63-8.21) and 7.75 cm (7.54-7.97) (P = 0.338), respectively. The mean NPC increased from 7.8 cm (95% CI: 7.55-8.05) in the age group 60-64 years to 8.83 cm (95% CI: 7.47-10.2) in the age group ≥ 80 years (P > 0.05). The mean (95% CI) NPC in emmetropic, myopic, and hyperopic individuals was 7.67 cm (95% CI: 7.33-8.02), 7.96 cm (7.56-8.37), and 7.87 cm (7.63-8.11), respectively (P = 0.378). There was no statistically significant relationship between NPC with education level, smoking, diabetes mellitus (DM), and hypertension (HT).

Conclusions: The NPC values found in this study were significantly lower (less remote) than the values reported in previous studies in similar age groups. The NPC had no significant relationship with age, sex, education level, smoking, DM, and HT.
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http://dx.doi.org/10.1038/s41433-021-01428-xDOI Listing
February 2021

Psychometric Assessment of the Persian Version of the Revised Convergence Insufficiency Symptom Survey in Young Adults with Convergence Insufficiency.

J Curr Ophthalmol 2020 Oct-Dec;32(4):395-401. Epub 2020 Dec 12.

Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran.

Purpose: To translate the Convergence Insufficiency Symptom Survey (CISS) to Persian and to assess its validity and reliability in a group of young adult Iranian patients with convergence insufficiency (CI).

Methods: The questionnaire was translated in backward and forward phases. Face validity was measured using a 6-point scale (very weak, weak, moderate, good, very good, best), and a score of ≥4 for each item indicated an acceptable face validity. The content validity was assessed using three indices of relevancy, clarity, and comprehensiveness. Relevancy and clarity were checked for each item and for the whole scale using a 4-point scale (1-undesirable, 2-relatively desirable, 3-desirable, 4-completely desirable), and Item Content Validity Index (I-CVI) and Scale Content Validity Index (S-CVI) were calculated for the above indices. Comprehensiveness was measured at the scale level using a 4-point scale (1-incomprehensive, 2-relatively comprehensive, 3-comprehensive, 4-totally comprehensive), and S-CVI was calculated. The internal consistency and test-retest reliability were assessed using Cronbach's alpha coefficient and interclass correlation coefficient (ICC), respectively. To evaluate discriminant validity, CI was categorized into mild, moderate, and severe stages, and the mean overall CISS score was compared between these groups.

Results: Thirty CI patients aged 18-34 years participated in this study. On face validity assessment, all items finally had a score of ≥4. As for relevancy and clarity, I-CVI was above 80% for all items, and S-CVI was 98.8% and 96.6%, respectively. The S-CVI was 100% for comprehensiveness. The overall Cronbach's coefficient and ICC were 0.77 and 0.95, respectively. There was a significant difference in the overall score between the three severity groups.

Conclusion: The Persian CISS is a valid and reliable tool for clinical and research applications.
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http://dx.doi.org/10.4103/JOCO.JOCO_194_20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7861096PMC
December 2020

Prevalence of amblyopia and its determinants in a rural population: a population-based cross-sectional study.

Strabismus 2021 Mar 16;29(1):10-18. Epub 2021 Jan 16.

Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran.

To determine the prevalence of amblyopia and its determinants in underserved rural villages of Iran. This population-based cross-sectional study was conducted in 3850 subjects selected from two underserved districts in the north (Kojur District, Nowshahr County, Mazandaran Province) and southwest (Shahyun District, Dezful County, Khuzestan Province) of Iran using multi-stage cluster sampling. The subjects underwent complete ophthalmic examinations including the measurement of uncorrected (UCVA) and best-corrected (BCVA) visual acuity, objective and subjective refraction, unilateral and alternate cover tests and ocular health examination. Amblyopia was defined as a reduction of BCVA to 20/30 or less in one eye or a 2-line interocular optotype acuity difference in the absence of any pathological factors. Of 3850 selected subjects, 3314 participated in the study (response rate = 86.08%). The mean age of the participants was 36.90 ± 20.21 years (range: 3-93 years). The prevalence and 95% confidence interval of total, bilateral, and unilateral amblyopia were 2.73% (2.17 to 3.38), 0.50% (0.28 to 0.83), and 2.23% (1.73 to 2.83), respectively. The most common type of amblyopia was anisometropic followed by strabismic and mixed. The lowest and highest prevalence was seen in the age group 6-20 years (1.36%; 0.65 to 2.49) and above 70 years (5.97%; 3.02 to 10.44), respectively. According to the results of multiple logistic regression analysis, compared to illiterate subjects, the odds ratio of amblyopia was 0.321 ( = .033) in subjects with High school education, 0.181 ( = .030) in subjects with secondary School education, and 0.486 ( = .041) in subjects with primary school education. The odds ratio of amblyopia for north villages residence vs southwest villages residence was 2.105 ( = .012). The odds ratio of amblyopia was 2.765 for age group>70 years vs. 6-20 years ( = .033). The prevalence of amblyopia was higher in north region, in participants with lower education level and older individuals. The high prevalence of amblyopia in older people may be due to the lack of screening programs in previous generations and consequently the lack of timely diagnosis and treatment.
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http://dx.doi.org/10.1080/09273972.2020.1871375DOI Listing
March 2021

Comparison of Corneal Higher-order Aberrations between Miniscleral and Hybrid Lenses in Keratoconus.

Optom Vis Sci 2020 09;97(9):749-753

Department of Psychiatric Nursing and Management, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Significance: Fitting specialty contact lenses (hybrid and miniscleral) can be a useful option in keratoconus patients to decrease higher-order aberrations (HOAs) and increase the quality of vision.

Purpose: The aim of the present study was to compare corneal HOAs between miniscleral and hybrid lenses in keratoconus patients.

Methods: The target population of this study was 37 patients with bilateral keratoconus aged 20 to 35 years who were referred to a specialized contact lens clinic by a corneal specialist. Pre-fitting examinations included objective and subjective refraction, measurement of uncorrected and best spectacle-corrected visual acuity, and measurement of corneal HOAs. Lens fitting was performed in the next step. Finally, post-fitting measurements including contact lens-corrected visual acuity and corneal HOAs were performed.

Results: The root mean square of the total HOAs significantly decreased after fitting both miniscleral and hybrid lens designs. There was a significant change in the third-order vertical coma and spherical aberration after fitting the miniscleral lens. In the hybrid lens group, a significant change was found only in vertical coma after fitting. There was no significant difference in the post-fitting HOA change between the two groups.

Conclusions: The results of this study showed the effectiveness of both miniscleral and hybrid lenses in decreasing HOAs in keratoconus patients. No significant difference was observed between these two lenses in this regard.
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http://dx.doi.org/10.1097/OPX.0000000000001560DOI Listing
September 2020

Agreement of Central Corneal Thickness Measurements between Scheimpflug Photography and Optical Low-Coherence Reflectometry in Children.

Semin Ophthalmol 2020 May 26;35(4):252-256. Epub 2020 Aug 26.

Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences , Tehran, Iran.

Purpose: Central corneal thickness (CCT) is a key indicator of the corneal health status and is therefore of clinical importance. The aim of the present study was to determine the agreement between Scheimpflug photography (SP) and optical low-coherence reflectometry (OLCR) systems in measuring the CCT in children.

Methods: In this cross-sectional study, the samples were selected from Shahroud schoolchildren using cluster sampling. The samples then underwent optometric examinations, including the measurement of visual acuity and refraction. CCT measurements were done by the SP and OLCR systems between 8 am and 4 pm. To evaluate the agreement between these devices, 95% limits of agreement (LoA) and interclass correlation coefficient (ICC) were reported.

Results: After applying the exclusion criteria, 4890 right eyes (53.2% male) were analyzed. The mean age of the students was 9.22 ± 1.72 years (range: 6-12 years). The mean CCT by the SP and OLCR systems was 555.30 ± 34.15 and 550.23 ± 35.11 µm, respectively. The 95% LoA between the two devices was -19.81 to 9.66 µm, and the ICC was 0.983. The CCT difference between the SP and OLCR systems was 5.61 µm in boys and 3.36 µm in girls. The CCT difference between the two devices was 6.41 µm in 6-year-old and 3.54 µm in 12-year-old children. The 95% LoA was -17.96 to 9.58 µm and -18.89 to 8.47 µm and the ICC was 0.987 and 0.984 in myopic and hyperopic subjects, respectively.

Conclusion: The results of this study showed a high agreement between OLCR and SP measurements of CCT in children.
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http://dx.doi.org/10.1080/08820538.2020.1810288DOI Listing
May 2020

Predicting initial base curve of the rigid contact lenses according to Javal keratometry findings in patients with keratoconus.

Cont Lens Anterior Eye 2021 Jun 1;44(3):101340. Epub 2020 Jun 1.

Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Purpose: To find an appropriate correlation between the base curve (BC) of rigid gas permeable (RGP) contact lenses and manual keratometry findings in Iranian patients with keratoconus (KCN) in order to simplify the fitting process, reduce the time, and lower the costs.

Method: This retrospective study was done in 121 eyes of 69 patients with KCN fitted with a specific trial set of RGP contact lenses over a 7-year period. The specifications of the final lens parameters included power, total diameter (1), and BC, the first two of which were fixed in all of the lenses in the trial set while BC was changed in 0.1-mm steps. Javal keratometer was used to measure keratometric values. The final fit assessment was performed based on the standard criterion of "three-point touch".

Result: Single and multiple linear correlations were done and the result was the following equation: BC = 2.455 (constant of the final multiple regression model) + 0.280 (steep keratometry) + 0.368 (flat keratometry) + 0.047 (corneal astigmatism) CONCLUSION: The advantages of this study include simplifying the RGP fitting process, reducing the examination time, lowering the costs, enhancing the confidence of the examiners and patients, easier lens fitting in remote places where more advanced devices are not accessible.
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http://dx.doi.org/10.1016/j.clae.2020.05.009DOI Listing
June 2021

High Prevalence of Asthenopia among a Population of University Students.

J Ophthalmic Vis Res 2019 Oct-Dec;14(4):474-482. Epub 2019 Oct 24.

Department of Psychiatric Nursing and Management, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Purpose: To determine the prevalence of asthenopia and its associated factors in a sample of university students in Iran.

Methods: In this cross-sectional study, participants were selected using multistage cluster sampling. Presence of at least one of the 10 symptoms-foreign body sensation, diplopia, blurred vision, eye swelling, dry eye, eye pain, difficulty in sustaining visual operations, decreased visual acuity, tearing, and photophobia-was considered as asthenopia. Ocular examinations, including uncorrected/corrected visual acuity measurement, objective/subjective refraction, cover test, amplitude of accommodation (AA), and near point of convergence (NPC) were performed.

Results: Of the 1,462 students (mean age: 22.8 3.1 years), 73% were women. The age- and gender-standardized prevalence was 70.9% (95% confidence interval [CI]: 68.3-73.5), 39.8% (95% CI: 36.4-43.1), and 19.7% (95% CI: 16.0-23.3) based on the presence of at least one, two, and three symptoms, respectively. The prevalence was significantly higher in females ( = 0.048), hyperopic students ( 0.001), and astigmatic participants ( 0.001). The mean AA and NPC were 9.7 2.6 D and 10.2 4.2 D ( = 0.008) and 7.0 2.1 cm and 7.7 3.9 cm ( 0.001) in participants with and without asthenopia, respectively. Multiple regression model revealed age (28-29 years), astigmatism, and NPC as independent associated factors (odds ratios: 3.51, 1.61, and 0.91, respectively).

Conclusion: This study shows relatively high prevalence of asthenopia in university students. Demographic factors and visual system disorders are important risk factors and timely correction of conditions may lead to decreased asthenopia.
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http://dx.doi.org/10.18502/jovr.v14i4.5455DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6825687PMC
October 2019

The prevalence of tropia, phoria and their types in a student population in Iran.

Strabismus 2020 03 23;28(1):35-41. Epub 2019 Dec 23.

Department of Psychiatric Nursing and Management, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran.

: The aim of this study is to determine the prevalence of tropia, phoria, and their types in Islamic Azad University students in Shahrekord, Iran.: Of 826 students that were invited, 752 participated in this cross-sectional study (response rate = 91.04%). After applying exclusion criteria, statistical analyses were performed on the data of 726 individuals. All participants underwent optometric tests including measurement of visual acuity, objective and subjective refraction, as well as binocular vision and ocular health examinations. The unilateral and alternate cover tests were done to detect the tropia and phoria at 6 m and 40 cm, respectively.: The overall prevalence and 95% confidence interval (CI) of tropia, exotropia, and esotropia were 1.5% (0.8 to 2.7), 1.2% (0.6 to 2.4), and 0.3% (0.1 to 1.1), respectively. The prevalence of esotropia was significantly higher in older age groups (24 years old) ( = .040) . The prevalence of exotropia was significantly higher in females (0.039) and in myopic individuals ( = .001). The overall prevalence and 95% CI of phoria, exophoria, and esophoria were 12.9% (10.7 to 15.6), 11.7% (9.6 to 14.3), and 1.2% (0.6 to 2.3), respectively. There was a significant difference in the overall prevalence of exophoria according to the age (0.021). The prevalence of esophoria was significantly higher in females ( = .039). The prevalence of exophoria was significantly higher in myopic participants ( = .003). Exophoria and exotropia were the most common types of phoria and tropia, respectively.: The prevalence of strabismus in university students was similar to the Iranian general population but lower than other countries. One in every 10 students had phoria, which was much lower than similar reports on Iranian populations; however, due to near-work activity, these students are prone to asthenopia, early visual fatigue, and decreased productivity. Therefore, it is suggested that university students also undergo screening programs to detect the cases of tropia and phoria.
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http://dx.doi.org/10.1080/09273972.2019.1697300DOI Listing
March 2020

The effect of base-in prism on vision-related symptoms and clinical characteristics of young adults with convergence insufficiency; a placebo-controlled randomised clinical trial.

Ophthalmic Physiol Opt 2020 01 3;40(1):8-16. Epub 2019 Dec 3.

Department of Psychiatric Nursing and Management, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Purpose: The aim of the present study was to evaluate the effect of base-in prism on symptoms and clinical characteristics of young adults with convergence insufficiency.

Methods: In this randomised clinical trial, 64 CI patients aged 18-38 years who presented to Bina Eye Hospital, Tehran, Iran between November 2018 and April 2019 were selected and randomly assigned to either prism or placebo groups. All participants underwent complete optometric examinations, including the measurement of visual acuity, objective and subjective refraction, and complete accommodative and binocular vision examinations. Clinical examinations were repeated after three months. The overall score of the Convergence Insufficiency Symptom Survey (CISS) was considered as the primary outcome measure. Secondary outcome measures included near exophoria, positive fusional vergence at near, near point of convergence, vergence facility, monocular accommodative facility, accommodative response, negative relative accommodation and accommodative convergence/accommodation (AC/A) ratio.

Results: The mean (S.D.) age of the participants was 25.5 (5.5) years and 44% of them were male. The mean CISS score was significantly lower in the prism group compared to the placebo group in the outcome examination (p < 0.001). Moreover, the values of monocular accommodative facility, accommodative response, and negative relative accommodation were significantly higher in the prism group versus the placebo group (p < 0.001). There was no significant difference in other parameters, including near positive fusional vergence, near point of convergence, vergence facility, and AC/A ratio between the two groups in the outcome examination (p > 0.10).

Conclusion: The base-in prism reduced symptoms in young adults with convergence insufficiency, while it had no significant effect on the near point of convergence, near positive fusional vergence, vergence facility and AC/A ratio. However, the results of this study only supports the symptomatic effectiveness of prism in the short term and further studies are needed to assess the long-term effect of prism.
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http://dx.doi.org/10.1111/opo.12654DOI Listing
January 2020

Demographic profile, clinical, and topographic characteristics of keratoconus patients attending at a tertiary eye center.

J Curr Ophthalmol 2019 Sep 23;31(3):268-274. Epub 2019 Feb 23.

Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Purpose: To evaluate the demographic profile, clinical, and topographic characteristics of keratoconus (KCN) patients attending at a subspecialty eye hospital in Tehran, Iran.

Methods: In this cross-sectional study, all patients who attended Noor Eye Hospital between March 2011 and March 2017 and had a diagnosis of KCN were identified, and the required number of patients was randomly selected. The following data were extracted from patient's records: age, sex, visual acuity, refraction, keratometry, pachymetry, and treatment procedures. The data of KCN laterality, severity, morphology, and cone location were also extracted by analyzing the corneal imaging maps.

Results: The records of 1080 eyes of 540 patients were evaluated. The mean age of the participants was 31.04 ± 8.54 years (range, 13-63 years), and 69.3% of the patients were male. The highest and lowest frequency of KCN was seen in the age group 20-30 years and above 50 years, respectively. Bilateral KCN was detected in 93.3% [95% confidence interval (CI): 91.68-94.75] of the subjects. 43.7% (95%CI: 32.88-54.48), 55.6% (95%CI: 44.73-66.38), and 0.8% (95%CI: 0.75-0.78) of the cases had nipple, oval, and globus cones, respectively. The cone was central in 52.1% (95%CI: 41.10-63.11), paracentral in 43.6% (95%CI: 36.13-51.04), and peripheral in 4.3% (95%CI: 00.76-7.86) of the cases. The frequency percentage of KCN according to severity was 15.2% (95%CI: 13.09-17.46), 56.4% (95%CI: 53.37-59.37), and 28.4% (95%CI: 25.75-31.21) for mild, moderate, and severe KCN, respectively. Among different parameters, only cone location had a significant association with age as the frequency of paracentral and peripheral cones increased with ageing ( = 0.002).

Conclusions: The mean age of KCN patients in our study was higher than similar studies in other Asian countries. KCN was bilateral in most cases with an oval morphology and central cone location. Most of the patients had moderate to severe KCN.
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http://dx.doi.org/10.1016/j.joco.2019.01.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6742613PMC
September 2019

Accommodative insufficiency in a student population in Iran.

J Optom 2019 Jul - Sep;12(3):161-167. Epub 2018 May 22.

Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran. Electronic address:

Purpose: To determine the prevalence of accommodative insufficiency (AI) and its relation with age, gender, and refractive errors in a college-age student population in Iran.

Methods: The present study was conducted cross-sectionally in 2017. All students had optometric tests including measurement of visual acuity, objective and subjective refraction, as well as binocular vision and accommodative examinations. Amplitude of accommodation was measured with the Donders' push-up method using the Royal Air Force (RAF) rule. Monocular accommodative facility was measured with ±2.00diopter flipper lenses. The accommodative response was tested using dynamic retinoscopy with the monocular estimation method (MEM).

Results: The prevalence of AI in the studied population was 4.07% (95% CI: 2.61-5.52). The rate was 6.04% (95% CI: 3.58-8.50) in females and 2.01% (95% CI: 0.53-3.48) in males, and logistic regression showed a significantly higher odds of AI in females (OR=3.14, 95% CI: 1.33-7.45, p-value=0.009). The prevalence of AI was 2.59% (95% CI: 0.55-7.56) in the 18-19-year-old age group and 4.08% (95% CI: 0.09-8.07) in the 24-25-year-old group (p-value=0.848). The prevalence of AI among emmetropic, myopic, and hyperopic individuals was 3.74% (95% CI: 1.88-5.61), 4.44% (95% CI: 2.07-6.81), and 5.26% (95% CI: 4.79-16.32), respectively (p-value=0.869). In the multiple regression model, only gender showed significant relationship with AI (Odds ratio=3.14, 95% CI: 1.33-7.45; p-values=0.009).

Conclusion: The prevalence of AI in the present study is lower than the most prevalence rates reported in previous studies. In the present study, gender and AI showed a strong association, such that AI prevalence was significantly higher in females than males.
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http://dx.doi.org/10.1016/j.optom.2018.03.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6612034PMC
July 2019

Near Point of Convergence in Iranian Schoolchildren: Normative Values and Associated Factors.

Strabismus 2018 09 18;26(3):126-132. Epub 2018 May 18.

g Department of Epidemiology and Biostatistics, School of Public Health , Tehran University of Medical Sciences , Tehran , Iran.

Purpose: To determine the distribution of near point of convergence (NPC) and its related factors in 6 to 12-year-old children.

Methods: In a cross-sectional study in 2015, the urban and rural children of Shahroud, north of Iran, were sampled. All rural schoolchildren were invited to the study, and in the urban area, we conducted random cluster sampling. Examinations included measurement of uncorrected and corrected visual acuity, manifest, subjective, and cycloplegic refraction. NPC and near point of accommodation (NPA) were measured with the best optical correction.

Results: Of the 6624 sampled schoolchildren, 5620 participated in the study, and after applying the exclusion criteria, the final analysis was conducted on data from 5444 students; their mean age was 9.24 ± 1.71 years (6-12 years) and 53.6% (n = 2918) of them were male. Mean NPC was 8.08 cm [95% confidence interval (CI): 7.96-8.19]; 8.07 cm (95% CI: 7.92-8.22) in males and 8.08 cm (95% CI: 7.91-8.25) in females (p = 0.954). NPC significantly recessed with age (p < 0.001). Mean NPC in emmetropic, myopic, and hyperopic children were 8.13, 7.04, and 8.23 cm, respectively (p < 0.001). The multiple linear regression model revealed significant associations for NPC with age (coefficient = 0.10, 0.95% CI: 0.05-0.15, p < 0.001), spherical equivalent refraction (coefficient = 0.17, 95% CI: 0.10-0.24, p < 0.001), and NPA (coefficient = 0.83, 0.95% CI: 0.76-0.90, p < 0.001).

Conclusion: Mean NPC in 6-12-year-old Iranian children was 8.08 cm, which is worse than values reported in previous studies. Mean NPC showed a slight recession with age. Myopic schoolchildren had the least remote and hyperopes had the most remote NPC values. More remote values of NPA were associated with receded NPC.
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http://dx.doi.org/10.1080/09273972.2018.1475493DOI Listing
September 2018

Distribution of IOP measured with an air puff tonometer in a young population.

J Curr Ophthalmol 2018 Mar 2;30(1):35-41. Epub 2017 Apr 2.

Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.

Purpose: To determine the normal range of intraocular pressure (IOP) in the young and its association with certain corneal parameters using a non-contact device.

Methods: Subjects were selected from students of Mashhad University of Medical Sciences through stratified sampling. All participants had visual acuity testing, corneal imaging, a comprehensive slit-lamp examination by an ophthalmologist, and IOP measurement using a non-contact air-puff tonometer.

Results: Of the 1280 invitees, 1073 (83.8%) participated, and 1027 were eligible. Mean IOP was 16.38 mmHg [95% confidence interval (CI): 16.22-16.53] in the total sample, 16.14 mmHg (95% CI: 15.84-16.45) in men, and 16.48 mmHg (95% CI: 16.31-16.66) in women. There was a significant IOP difference between myopes and emmetropes ( = 0.031). Based on the multiple linear regression model, IOP associated directly with age and central corneal thickness (CCT), and inversely with corneal diameter, spherical equivalent (SE), and keratoconus. Based on standardized coefficients of the regression model, CCT and SE had the strongest association with IOP.

Conclusions: In the present study, we demonstrated the IOP distribution in a young population using a non-contact method. CCT and SE were strongly associated with IOP.
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http://dx.doi.org/10.1016/j.joco.2016.11.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5859631PMC
March 2018

The Prevalence of Amblyopia and Its Determinants in a Population-based Study.

Strabismus 2017 12 16;25(4):176-183. Epub 2017 Nov 16.

f Department of Medical Surgical Nursing , School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences , Tehran , Iran.

Purpose: To determine the prevalence of amblyopia and its determinants in a population-based study in Mashhad County, Iran.

Methods: This cross-sectional, population-based study was conducted on the population of Mashhad County aged >1 year using randomized stratified cluster sampling. Examinations were performed after selection of the participants and their free transportation to the sampling site. The examinations included the measurement of uncorrected and corrected visual acuity, cycloplegic and non-cycloplegic refraction, cover testing, slit-lamp biomicroscopy, and ophthalmoscopy. In this study, amblyopia was defined as best corrected visual acuity (BCVA) of 20/30 or less or 2-line interocular optotype acuity differences with no pathology.

Results: After considering the exclusion criteria, the data of 2739 individuals, 65.6% of whom were women, were analyzed. The mean age of the participants was 29.5±17.5 years. The prevalence of amblyopia was 4.6% (95% CI: 3.77%-5.43%) in the total population. The lowest prevalence was 2.24% in the age group 5-15 years (95% CI: 0.99%-3.48%) and the highest prevalence was 7.14% in the age group 55-65 years (95% CI: 2.64%-11.56%). Anisometropic amblyopia was observed in 45.24% of the amblyopic participants. Isometropic, mixed (strabismic/anisometropic), and strabismic amblyopia were other common causes of amblyopia, with a prevalence of 24.6%, 16.67%, and 13.49% in amblyopic patients, respectively. The odds ratio (OR) of having amblyopia for each 1-year increase in age was 1.02 (95% CI: 1.01-1.03). Amblyopia was less common in people with better socioeconomic status.

Conclusion: This study showed the prevalence of amblyopia in all age groups in a population-based study for the first time. The findings of this study regarding the relatively high prevalence of amblyopia in the older population and its lower prevalence in young people indicate attention to amblyopia in recent years.
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http://dx.doi.org/10.1080/09273972.2017.1391849DOI Listing
December 2017

The incidence of needle stick and sharp injuries and their associations with visual function among hospital nurses.

J Curr Ophthalmol 2017 Sep 3;29(3):214-220. Epub 2017 Jul 3.

Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.

Purpose: To determine the one-year incidence of needle stick and sharp injuries (NSIs and SIs) and their associations with visual function among Iranian nurses.

Methods: In this cross-sectional study, 278 nurses working at one hospital were selected through stratified random sampling. After applying the exclusion criteria, the final analysis was performed on the data of 267 nurses. The data of occupational injuries were collected through a researcher-administered questionnaire. Visual function indices including distance and near best corrected visual acuities (BCVAs), color vision, stereoacuity, distance and near heterophorias, accommodative amplitude and facility, contrast sensitivity (CS) for high and low spatial frequencies (SFs), near point of convergence (NPC), saccadic and pursuit eye movements, distance and near convergence and divergence fusional reserves and peripheral vision were evaluated through optometric examinations using standard protocols.

Results: The one-year incidence of NSIs and SIs was 41.2% [95% Confidence interval (CI): 35.3-47.1] and 19.1% (95% CI: 14.4-23.8), respectively. Color vision deficiency, pursuit deficiency, abnormal near heterophoria, and decreased CS for high SF had a significant association with the increased incidence of NSIs with odds ratios of 3.26, 2.32, and 1.35, respectively. Moreover, saccadic deficiency, abnormal near heterophoria, and decreased near fusional divergence reserve were significantly associated with the increased incidence of SIs with odds ratios of 2.42, 2.40, and 1.27, respectively.

Conclusions: Our findings showed a relatively high incidence of NSIs and SIs in Iranian nurses and their associations with some visual function indices. Therefore, pre-employment and periodic visual examinations are recommended to detect and remove the corresponding visual risk factors. Moreover, preventive strategies should be adopted to decrease the occurrence of the aforementioned injuries.
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http://dx.doi.org/10.1016/j.joco.2017.06.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5587247PMC
September 2017

The prevalence of refractive errors among adult rural populations in Iran.

Clin Exp Optom 2018 Jan 12;101(1):84-89. Epub 2017 Jul 12.

Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Purpose: The aim was to determine the prevalence of myopia and hyperopia and related factors in underserved rural areas in Iran.

Methods: Under random cluster sampling, two rural regions were randomly selected in the north and southwest of the country, and 3,061 persons over 15 years of age were invited into the study. After selecting samples, all participants had refraction, measurement of uncorrected vision and visual acuity and ocular health examination by slitlamp biomicroscopy.

Results: Of the 3,061 invitees, 2,575 participated in the study (response rate: 84.1 per cent). After excluding those who met the exclusion criteria or had missing refractive data, eventually there were 2,518 subjects available for this analysis. The mean age of the participants was 44.3 ± 17.5 years (range: 16 to 93 years) and 1,460 of them (58.0 per cent) were female. The overall prevalence of myopia and hyperopia in this study was 25.2 per cent (95 per cent CI: 23.2 to 27.2) and 22.5 per cent (95 per cent CI: 20.6 to 24.4), respectively. The prevalence of myopia increased from 20.9 per cent in participants 16 to 20 years to 32.9 per cent in the 21 to 30 years age group, declined up to the age of 60 years and increased again afterwards. The lowest prevalence was 6.8 per cent observed in the 16 to 20 years age group and the highest was 45.8 per cent in 61- to 70-year-olds. In the final logistic regression model, myopia significantly associated with age, higher education levels and cataracts, while hyperopia associated with age, lower education levels and male gender.

Conclusion: In our study, the prevalence of myopia was lower and the prevalence of hyperopia was higher compared to most previous studies. The findings of this study imply that refractive errors vary by age.
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http://dx.doi.org/10.1111/cxo.12565DOI Listing
January 2018

The Prevalence of Age-Related Eye Disease in an Elderly Population.

Ophthalmic Epidemiol 2017 08 28;24(4):222-228. Epub 2017 Jun 28.

f Department of Optometry, School of Paramedical Sciences , Mashhad University of Medical Sciences , Mashhad , Iran.

Purpose: To determine the prevalence of cataracts, age-related macular degeneration (AMD), glaucoma, and diabetic retinopathy (DR) in Iranians over the age of 54 years.

Methods: Through a cross-sectional study using randomized cluster sampling, 60 clusters were selected in Sari, a city in the North of Iran. In each cluster, 20 people over 54 years of age were chosen systematically and were invited to participate in the study. After enrollment, all participants had optometric and ophthalmologic exams including slit lamp biomicroscopy and fundoscopy.

Results: Of the 1185 selected persons, 937 (79.1%) participated in this study (age range 55-87 years). The prevalence of cataracts, AMD, glaucoma, and DR in at least one eye was 29.6% (95% confidence interval [CI] 26.6-32.5), 5.8% (95% CI: 4.3-7.3), 3.7% (95% CI: 2.5-5.0), and 2.7% (95% CI: 1.6-3.7), respectively. All prevalences significantly increased with aging. AMD was more prevalent in men (7.4%) than women (4.4%) (p = 0.054). Overall, 35.8% (95% CI: 32.7-38.8) of participants had at least one of the four conditions; this rate was 27.4% for the 55-59-year old age group and 52.4% for those over 75 years of age.

Conclusion: Overall, 35.8% of the studied population had at least one of the four diseases. Cataracts, followed by AMD, are the most common age-related eye diseases in the Iranian population, and thus, precise planning along with enhanced diagnostic and therapeutic facilities are necessary.
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http://dx.doi.org/10.1080/09286586.2016.1270335DOI Listing
August 2017

The prevalence of color vision deficiency in the northeast of Iran.

J Curr Ophthalmol 2019 Mar 9;31(1):80-85. Epub 2017 Jun 9.

Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.

Purpose: To determine the prevalence of color vision deficiency (CVD) in the northeast of Iran.

Methods: This cross-sectional, population-based study was conducted in Mashhad, in the northeast of Iran. Multistage cluster sampling was used for selecting the participants. After preliminary screening, the subjects underwent a complete ophthalmic examination. The examination included the measurement of visual acuity, refraction, and slit-lamp biomicroscopy. The Farnsworth D-15 test was used to detect CVD. The color vision test was done with the best optical correction.

Results: Of the 4453 invitees, 3132 participated in the study (response rate: 70.4%). The overall prevalence of CVD in this study was 13.93% [95% confidence interval (CI): 12.44-15.41]. The prevalence of CVD in males and females was 15.85% (95% CI: 13.26-18.44) and 12.96% (95% CI: 11.22-14.71), respectively. The most prevalent types of CVD were tritanopia (6.96%; 95% CI: 5.84-8.08), deuteranopia (3.92%; 95% CI: 3.14-4.70) and tritanomalous (2.21%; 95% CI: 1.55-2.86), respectively. According to the results of logistic regression, the odds of having protanopia were higher in females than males [Odds ratio (OR) = 4.80; 95% CI: 1.20-19.18]. The odds of having deuteranopia were lower in females than males (OR = 0.52; 95% CI: 0.35-0.76). The odds of having CVD were lower in 16-30 (OR = 0.52; 95% CI: 0.37-0.73) and higher in 46-60 (OR: 1.41; 95% CI: 1.01-1.97) year age groups compared to 7-15 year age group. The odds of having tritanopia in 16-30 and 46-60 year age groups was 0.56 (95% CI: 0.35-0.90) and 1.79 (95% CI: 1.19-2.67) compared to 7-15 year age groups, respectively.

Conclusion: The prevalence of CVD was high in this study, especially in males and people over 46 years of age. Planning for involvement of ocular disease control programs in health care systems can be helpful in the reduction of CVD and improving the quality of life in affected patients.
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http://dx.doi.org/10.1016/j.joco.2017.05.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6407150PMC
March 2019

The prevalence of refractive errors in 5-15 year-old population of two underserved rural areas of Iran.

J Curr Ophthalmol 2018 Sep 29;30(3):250-254. Epub 2017 May 29.

Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Purpose: To determine the prevalence of hyperopia and myopia and their associations with age and gender in 5- to 15-year-old children in underserved rural areas in Iran.

Methods: In this cross-sectional study, sampling was done using a multistage cluster sampling method from two underprivileged rural regions in Iran, and 3851 persons over 1 year old of age were invited to the study. After inviting the selected participants, examinations were conducted at a designated site in the selected villages. All participants underwent measurements of uncorrected and corrected visual acuity, manifest refraction, and a slit-lamp examination. Cycloplegic refraction was done by instilling cyclopentolate 1% eye drops in under 15-year-old participants.

Results: Of the 3851 selected persons, 3314 subjects participated (86.5%), and of these, 602 were in the 5-15 year age group. The prevalence of myopia and hyperopia in the studied children was 2.60% [95% confidence interval (CI): 1.10-4.10] and 4.00% (95% CI: 1.84-6.15), respectively. The prevalence of myopia in male and female children was 2.65% and 2.55%, respectively ( = 0.951). The prevalence of hyperopia in male and female children was 2.83% and 5.25%, respectively ( = 0.130). The prevalence of myopia in the villages of southwest and north was 2.42% and 3.09%, respectively ( = 0.618), and the prevalence of hyperopia was 4.71% and 2.10%, respectively ( = 0.0056).

Conclusion: The present report is a brief description of the status of refractive errors in children residing in underprivileged villages of two rural districts in Iran. As presented, the prevalence of myopia is not high, although the prevalence of hyperopia is in the mid-range compared to previous studies.
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http://dx.doi.org/10.1016/j.joco.2017.05.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6127353PMC
September 2018

Does Hofstetter's equation predict the real amplitude of accommodation in children?

Clin Exp Optom 2018 Jan 17;101(1):123-128. Epub 2017 May 17.

Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Purpose: The aim was to determine the distribution and associated factors of accommodative amplitude (AA) in six- to 12-year-old children and compare the results with those calculated using Hofstetter's formula.

Methods: In a cross-sectional study in 2015, random sampling was done from urban and rural populations of Shahroud, northern Iran. Participating schoolchildren were examined for manifest, cycloplegic and subjective refraction, as well as uncorrected vision and visual acuity. The AA was measured with Donders' push-up method using a ruler. The near point of convergence (NPC) was also measured.

Results: Of the 6,624 selected children, 5,620 participated in the study and after applying the exclusion criteria, the final analyses were done on data from 5,444 schoolchildren. The mean age of the final sample was 9.24 ± 1.71 years (from six to 12 years) and 53.6 per cent (n = 2,919) were boys. Mean measured AA was 14.44 D (95 per cent confidence interval [CI]: 14.33-14.55). In all age groups, the mean measured AA was less than the predicted mean value calculated with the Hofstetter's equation. Mean measured AA was 14.44 D (95 per cent CI: 14.28-14.59) and 14.45 D (95 per cent CI: 14.29-14.6) in boys and girls, respectively (p = 0.926). AA significantly declined with age (coefficient: -0.18, 95 per cent CI: -0.23 to -0.12, p < 0.001). Mean AA in emmetropic, myopic and hyperopic children was 14.31 D, 17.30 D and 14.87 D, respectively. Older age (coefficient = -0.18), living in rural areas (coefficient = -0.48) and NPC (coefficient = 0.47) inversely related with AA and higher AA was associated with a shift of the spherical equivalent refraction toward myopia (coefficient = -0.41).

Conclusion: The differences among groups with different types of refractive error and high AA in children with myopia are important findings of this study. The results of the present study suggest that Hofstetter's formula provides inaccurate AA estimates in children and thus, the interpretation of this index requires further population-based studies in different racial and ethnic groups.
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http://dx.doi.org/10.1111/cxo.12550DOI Listing
January 2018

The Prevalence of Strabismus, Heterophorias, and Their Associated Factors in Underserved Rural Areas of Iran.

Strabismus 2017 06 2;25(2):60-66. Epub 2017 May 2.

g Department of Medical Surgical Nursing, School of Nursing and Midwifery , Shahid Beheshti University of Medical Sciences , Tehran , Iran.

Purpose: To determine the prevalence of different types of strabismus and heterophoria and their associated factors in underserved rural areas of Iran.

Methods: Two rural areas in the north and southwest of Iran were randomly sampled using multistage cluster sampling. Individuals aged over 1 year, totaling 3851, were invited to participate in the study. In addition to collecting demographic data, optometric examinations were performed for each participant. Unilateral and alternating cover tests were performed at far (6 m) and near (40 cm) to detect tropia and phoria, respectively, and the magnitude of the deviation was measured using alternating cover test and prism bar. Tropia was defined as the presence of constant unilateral or alternating horizontal strabismus (exotropia or esotropia) at either far or near fixation distances. Far and near exophoria were defined as more than 3 prism diopters (PD) and 9 PD of exophoria at far and near fixation distances, respectively. Far esophoria was defined as more than 1 PD of esophoria at far. Near esophoria was defined as any amount of esophoria at near.

Results: Of 3851 selected individuals, 3314 (86.5%) participated in the study. After excluding those who met the exclusion criteria or had missing data, eventually there were 3248 subjects available for this analysis. The prevalence of tropia and phoria was 4.3% (95% CI: 3.28-5.33) and 28.37% (95% CI: 19.12 -37.61), respectively. The prevalence of exotropia and esotropia was 3.87% (95% CI: 2.77-4.98) and 0.43% (95% CI: 0.19-0.67), respectively. The prevalence of near exophoria, far exophoria, near esophoria, and far esophoria was 25.96 (95% CI: 16.71-35.2), 4.82% (95% CI: 0.23-9.41), 0.47% (95% CI: 0.2-0.75), and 0.34% (95% CI: 0.06-0.63), respectively. In this study, the prevalence of tropia had no significant association with age, sex, living place, and refractive errors (all P values >0.05), while the prevalence of phoria increased significantly with increasing age (P<0.001) and was also significantly associated with living place (P<0.001).

Conclusion: The prevalence of tropia and phoria was high in our study. Moreover, the prevalence of exotropia and exophoria was higher than esotropia and esophoria. The prevalence of phoria was significantly higher in older age groups and in the participants living in the southern villages.
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http://dx.doi.org/10.1080/09273972.2017.1317820DOI Listing
June 2017

Sensitivity and Specificity of Preschool Vision Screening in Iran.

Iran J Public Health 2017 Feb;46(2):207-215

Dept. of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Background: To determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the National Vision Screening Program for 7 yr old children in Iran.

Methods: In this cross-sectional study, eight cities in Iran were selected through multistage cluster sampling. Selected cities were Sari, Birjand, Ardabil, Mashhad, Bandar Abbas, Dezful, Yazd, and Arak, in Iran in 2013. Totally, 4614 schoolchildren were selected, 4106 of which participated in the study. An optometrist at the school site conducted all vision tests. Results were compared against those recorded on each child's health card. Those with an uncorrected visual acuity worse than 20/25 in at least one eye screened positive for a vision problem.

Results: 8.49% [95% confidence interval, 7.65 to 9.39] of the examinees had a vision problem. The sensitivity rate of the school entry screening was 38.15% (95% CI, 33.01 to 43.50) and the specificity rate was 93.11 (95%CI 92.25 to 93.90). The positive and negative predictive values were 33.93 (29.24 to 38.88) and 94.19 (93.39 to 94.93), respectively. Sensitivity and specificity rates did not significantly differ between boys and girls. For the uncorrected visual acuity tested by public health care workers compared to optometrists, the area under the ROC surface was 0.741 (<0.001). The best-associated criterion was an uncorrected visual acuity more than 0.05 LogMAR with 67.3% sensitivity and 74.7% specificity.

Conclusion: The validity of the school entry vision screening by health workers is low. To reduce false negative rates, some supplementary examinations such as refraction and near visual acuity measurements as well as further training of screeners should be considered.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5402779PMC
February 2017

The distribution of orbscan indices in young population.

J Curr Ophthalmol 2017 Mar 31;29(1):39-44. Epub 2016 Aug 31.

Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.

Purpose: To determine the distribution of anterior eye biometry indices, such as keratometry pachymetry, anterior chamber depth (ACD), pupil diameter, and corneal diameter, as measured by Orbscan instrument in a young Iranian population.

Methods: A cross-sectional study was conducted, and subjects were selected through multistage cluster sampling from the students of Mashhad University of Medical Sciences. Objective and subjective refraction were performed followed by Orbscan imaging.

Results: A total of 1330 subjects were selected, 1121 of which participated in the study. After applying the exclusion criteria, the final analysis was performed on the data of 1051 subjects. The mean age of the participants was 26.1 ± 3.2 years (19-34 years old). The mean ± SD and 95% confidence interval (CI) of maximum keratometry, minimum keratometry, pupil diameter, corneal diameter, ACD, and central corneal thickness was 44.5 ± 1.7 (44.4-44.6), 43.1 ± 1.6 (43.0-43.2), 4.3 ± 0.9 (4.3-4.4), 11.7 ± 0.4 (11.7-11.7), 3.7 ± 0.3 (3.6-3.7), and 550.5 ± 35 (548.4-552.6), respectively. After adjusting for age and the mean spherical equivalent (MSE), maximum keratometry, minimum keratometry, central corneal thickness, and the thinnest pachymetry were statistically significantly higher in female subjects (P < 0.001) whilst the corneal diameter and ACD were higher in male subjects (P < 0.001). The pupil diameter and ACD showed statistically significant changes with age (P < 0.001). The MSE was only correlated with maximum keratometry and ACD (P < 0.001).

Conclusion: In this study, the distribution of Orbscan measurements for the anterior segment parameters was reported in a large sample of the young Iranian population. Age, gender, and refractive error may affect the orbscan measurements.
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http://dx.doi.org/10.1016/j.joco.2016.08.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5362392PMC
March 2017