Publications by authors named "Abbasali Yekta"

147 Publications

The Distribution of Keratometry in a Population Based Study.

J Curr Ophthalmol 2021 Jan-Mar;33(1):17-22. Epub 2021 Mar 26.

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

Purpose: To determine the distribution of keratometry values in a wide age range of 6-90 years.

Methods: In this cross-sectional study, samples were selected from two villages in Iran using multi-stage random cluster sampling. After completing optometry and ophthalmic examinations for all cases, corneal imaging was done using Pentacam, and keratometry values were determined.

Results: Of the 3851 selected people, 3314 people participated in the study, and after applying the exclusion criteria, analyses were done on data from 2672 people. Mean age of the participants was 36.30 ± 18.51 years (from 6 to 90 years). Mean keratometry (mean-K) in flat and steep meridians was 42.98 (42.9-43.06) diopters (D) and 43.98 (43.91-44.07) D, respectively. Average of mean-K was 43.48 (43.41-43.56) D. Mean-K increased linearly up to the age of 70 years, and the cornea became slightly flat afterwards (coefficient = 0.01; < 0.001). Mean-K was significantly higher in females ( < 0.001). Myopic cases had the highest mean-K ( < 0.001). The correlation of mean-K with age, gender, central corneal thickness, anterior chamber depth, pupil diameter, and spherical equivalent was investigated in a multiple regression model. Only older age and female gender showed a statistically significant association with mean-K. Overall, 31.62% (29.14-34.09) of the sample in this study had at least 1.0 D of corneal astigmatism.

Conclusions: This is one of the few studies worldwide that demonstrates changes in keratometry in a wide age range from childhood to old age. Results indicated that age and gender are variables associated with keratometry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.joco.2019.06.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8102948PMC
March 2021

Agreement of Fixation Disparity Curve between Two Different Instruments.

Optom Vis Sci 2021 Jun 2. Epub 2021 Jun 2.

Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/OPX.0000000000001708DOI Listing
June 2021

Convergence Insufficiency in the Geriatric Population.

Optom Vis Sci 2021 Jun 2. Epub 2021 Jun 2.

Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran Department of Optometry, Mashhad University of Medical Sciences, Mashhad, Iran Eye Research Center, Tehran University of Medical Sciences, Tehran, Iran Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Department of Ophthalmology, Feiz Hospital, Isfahan University of Medical Sciences, Isfahan, Iran Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/OPX.0000000000001709DOI Listing
June 2021

Distribution of near Point of Convergence, near Point of Accommodation, Accommodative Facility and Refractive Errors in a Rural Population Living in Northern Iran.

J Binocul Vis Ocul Motil 2021 May 25:1-6. Epub 2021 May 25.

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

: To evaluate near point of convergence (NPC), near point of accommodation (NPA), and accommodative facility (AF) in order to determine their normative data in a rural population.: The target population for this population-based, cross-sectional study was people living in rural areas. Each subject underwent extensive optometric and ophthalmic examinations, including the measurement of visual acuity, refraction, NPA, NPC, and AF.: The data of 1113 individuals was analyzed of whom 58.8% (n = 576) were women. The mean age of the participants was 15.26 ± 7.38 years (range: 6-30 years). The mean spherical equivalent of the subjects was 0.16 ± 0.63 D. The prevalence of myopia, hyperopia and astigmatism was 16.28% (13.97-18.58), 5.97% (4.49-7.44), 11.93% (9.91-13.95) in this study, respectively The mean and 95% confidence interval of NPC, NPA, and binocular accommodative facility (BAF) was 6.99 cm (6.84-7.15), 9.91 cm (9.71-10.11), and 9.84 cpm (9.63-10.06), respectively. A significant correlation was found between age and the parameters such that all evaluated parameters worsened significantly with age ( < .001).: The results of the present study showed the normal ranges of NPA, NPC, and BAF in a 6-30 year-old population living in rural areas of northern Iran. These parameters changed significantly with age.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/2576117X.2021.1927291DOI 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/08820538.2021.1910318DOI Listing
April 2021

Meibomian gland dysfunction in geriatric population: tehran geriatric eye study.

Int Ophthalmol 2021 Mar 24. Epub 2021 Mar 24.

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

Purpose: To determine the prevalence of Meibomian gland dysfunction (MGD) and its risk factors in an elderly Iranian population METHODS: This cross-sectional study was conducted in 2019. The target population was the subjects aged 60 and over living in Tehran. Multistage cluster sampling was done to select the subjects from all Tehran districts. After an initial interview, all subjects underwent complete ophthalmic examinations including the measurement of visual acuity and refraction as well as slit lamp biomicroscopy to evaluate Meibomian glands.

Results: Of 3791 selected subjects, 3310 participated in the study. The data of 3284 participants were analyzed. The mean age of the subjects was 68.24 ± 6.53 years (range: 60-97 years) and 57.8% of them were female. The total prevalence of MGD was 71.2% (68.3-74.1), and 38.1% (8.35-40.4), 30.3% (27.4-33.2), and 2.8% (2-3.6) of the subjects had MGD stage 2, 3, and 4, respectively. The prevalence of MGD was significantly higher in men (p < 0.001) and increased with age from 64.4% in the age group 60-64 years to 82.4% in subjects aged 80 years and over. There was no significant difference in the prevalence of MGD between smokers and nonsmokers; however, severe MGD was more common in smokers. The prevalence of MGD was 76.3% and 68.52% in subjects with and without a history of ocular surgery, respectively. The prevalence of MGD stage 3 and 4 was higher in subjects with a history of ocular surgery.

Conclusions: In line with the results of other studies in Asian countries, this study found a high prevalence of MGD in an elderly population of Iran. It was found that male gender and advanced age were risk factors of MGD and smoking and history of ocular surgery might worsen this disease in MGD patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10792-021-01812-2DOI Listing
March 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/08164622.2021.1878828DOI Listing
February 2021

Distribution of Eccentricity in Children Aged 6-12 Years.

Semin Ophthalmol 2021 Mar 9:1-5. Epub 2021 Mar 9.

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

Purpose: To determine the distribution of eccentricity and its association with some biometric and demographic parameters.

Methods: In this cross-sectional study, the target population was primary school children aged 6 to 12 years from Shahroud, northeast Iran. Scheimpflug imaging was done using the Pentacam. Multiple linear regression analysis was applied to study the association between Eccentricity (ECC) and independent variables like age, sex, living place as well as biometric parameters.

Results: Of the 6624 selected students, 5620 participated in the study of whom 4968 were eligible for analysis in this study. About half (52.4%) of the students were boys. The mean ECC was 0.600 (95% CI: 0.597-0.602) in total, 0.597 (95% CI: 0.594-0.600) in boys and 0.603 (95% CI: 0.599-0.607) in girls. The mean ECC was 0.611 in 6-year-old and 0.588 in 12-year-old children. The mean ECC was 0.590 in rural and 0.601 in urban children. The mean ECC was 0.600, 0.604, and 0.604 in emmetropic, myopic, and hyperopic children, respectively. Multiple linear regression analysis showed that ECC decreased with age (Coefficient: -0.004; 95%CI: -0.006 to -0.003), was higher in urban areas (Coefficient: 0.008; 95%CI: 0.002 to 0.014), had a direct association with axial length, and had an indirect association with lens thickness, central corneal thickness, and anterior chamber depth.

Conclusion: The cornea had a prolate shape in children and eccentricity value decreased with age. The results of this study add to the existing knowledge and can be used in differentiating normal from abnormal corneal shapes in children.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/08820538.2021.1897853DOI Listing
March 2021

The prevalence of anterior blepharitis in an elderly population of Iran; The Tehran geriatric eye study.

Cont Lens Anterior Eye 2021 Feb 23:101429. Epub 2021 Feb 23.

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

Purpose: To determine the age and sex-standardized prevalence and risk factors of anterior blepharitis in a geriatric population in "…".

Methods: This population-based study was conducted on the elderly population (over 60 years of age) of Tehran, the capital of "…" in 2019. Examinations included visual acuity assessment, refraction, and complete slit lamp examination. After the diagnosis of anterior blepharitis, its type (staphylococcal vs. seborrheic) was also determined. Multiple logistic regression was used to determine the risk factors of the disease.

Results: 3310 individuals participated in this study. The data of 3284 participants were available for this report. The mean age of the participants was 68.6 ± 24.5 years, and (57.8 %) were female. Age and sex-standardized prevalence of anterior blepharitis was 33.5 % (95 % CI: 30.6-36.5%) of which 96.5 % were bilateral. The prevalence of seborrheic and staphylococcal types was 22.4 % (95 % CI: 19.9-25.2%) and 11.3 % (95 % CI: 9.2-13.5%), respectively. According to the multiple logistic regression, the prevalence of anterior blepharitis was positively related to age over 80 years (P < 0.001) and male gender (P < 0.001), and inversely related to education level (P = 0.033). No significant relationship was found between anterior blepharitis and other variables including systemic hypertension, diabetes mellitus, hyperlipidemia, smoking, socioeconomic status, and history of the previous eye examination. Sex had the greatest effect on developing anterior blepharitis (standardized coefficient: 0.325).

Conclusion: The results of this study showed a relatively high prevalence of anterior blepharitis in the elderly population which requires special attention of the health system to inform and control this disease through continuous training of the media and regional health centers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.clae.2021.02.015DOI Listing
February 2021

Investigation of Economic Inequality in Eye Care Services Utilization and Its Determinants in Rural Regions Using the Oaxaca- Blinder Decomposition Approach.

Semin Ophthalmol 2021 Feb 21:1-6. Epub 2021 Feb 21.

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

: This study was conducted to determine economic inequality in Eye Care Services Utilization (ECSU) and its determinants in the underserved rural population of Iran: In this population-based study, two underserved regions in the north and southwest of Iran were randomly selected and 3850 individuals living in these regions were invited to participate in the study. ESCU was defined as a history of at least one optometric or ophthalmologic visit during the lifetime. Concentration index (C) was used to evaluate economic inequality and the Oaxaca- Blinder decomposition was applied to decompose the gap between the rich and poor.: Of 3851 individuals, 3314 participated in the study (response rate: 86%). The data of 3094 participants were analyzed. The concentration index was 0.139 (95% CI: 0.218 - 0.590), indicating a pro-rich inequality in the ECSU. The ECSU was 12.38% (10.46 to 14.31) in the poor and 21.15% (18.38 to 23.92) in the rich, and the gap between them was about 90% in favor of the rich ( < 00.001). A marked percentage of the gap was due to the explained portion (b: -11.49; < .001). The unexplained portion coefficient was b: 2.72 (p: 0.020). In the explained portion, economic status (b: -12.37; < .001) and age (b: 0.90; p: 0.021) caused inequality in favor of the rich and poor respectively while only economic status (b:-21.1; < .001) had a significant effect on inequality in favor of the rich in the unexplained portion.: There is a significant pro-rich inequality in ECSU in the rural areas of Iran. A major portion of this inequality is related to differences in age and economic status between the two groups. Economic status has direct and indirect effects on inequality in ECSU; therefore, health policymakers should focus on economic improvement to remove the gap.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/08820538.2021.1890782DOI 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41433-021-01428-xDOI Listing
February 2021

Keratoconus Indices and their Determinants in Healthy Eyes of a Rural Population.

J Curr Ophthalmol 2020 Oct-Dec;32(4):343-348. Epub 2020 Dec 12.

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

Purpose: To determine the distribution of keratoconus indices in a 5-93-year-old healthy eyes of a rural population in Iran.

Methods: In this cross-sectional study, multi-stage cluster sampling was applied to select subjects from two villages in the north and southwest of Iran. After obtaining informed consent, all subjects underwent ophthalmologic and optometric examinations. Corneal imaging by the Pentacam was done in subjects above 5 years between 9 a.m. and 2 p.m., at least 3 h after wakeup. All subjects who had abnormal keratoconus indices were excluded. Our main outcome was keratometry-flat (K), keratometry-steep (K), keratoconus index (KI), and central keratoconus index (CKI).

Results: The mean ± standard deviation of K, K, KI, and CKI was 43.12 ± 1.74, 44.25 ± 1.65, 1.02 ± 0.02, and 1.01 ± 0.01, respectively. According to multiple linear regression analysis, the mean index surface variance (ISV) (b: -1.367, < 0.001), index vertical asymmetry (IVA) (b: -0.012, < 0.001), KI (b: -0.011, < 0.001), CKI (b: -0.001, < 0.001), index height asymmetry (IHA) (b: -0.491, P: 0.005), and index height decentration (IHD) (b: -0.001, < 0.001) were lower in men compared to women. Moreover, age had an indirect association with ISV (b: -0.030, < 0.001) and average pachymetric progression index (RPI_avg) (b: -0.001, < 0.001), and a direct association with KI, CKI, and IHA. Spherical equivalence had an indirect association with KI (b: -0.001, < 0.001) and RPI_avg (b: -0.004, < 0.001) and a direct association with CKI (b: 0.001, < 0.001). Among all variables, sex had the greatest impact on ISV, IVA, KI, IHA, IHD, and minimum sagittal curvature.

Conclusions: The Keratoconus indices of our study were similar to other studies. Although age, living place, and type of refractive error were associated with some indices, sex was the strongest determinant of Keratoconus indices in a population of healthy eyes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.joco.2019.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7861110PMC
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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/09273972.2020.1871375DOI Listing
March 2021

Comparison of ocular aberrations in three types of rigid gas permeable lenses in keratoconus patients.

Rom J Ophthalmol 2020 Jul-Sep;64(3):280-284

Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.

To determine the effect of different types of Rigid Gas Permeable (RGP) contact lenses on ocular aberrations in patients with keratoconus. Eighteen eyes of young patients with mild to moderate keratoconus were selected. General ocular examinations such as refraction, visual acuity, and ocular aberrations were performed. Three types of RGP contact lenses, i.e., Boston, Senso Select and Wohlk, were fitted using the cross over method. Repeated measures analysis of variance and Mauchly's test of sphericity were used to compare the average of residual high order aberrations and visual acuity after fitting each type of lens. Vertical coma was -0.271 ± 0.37 µm before fitting and decreased to 0.081 ± 0.08 µm with Boston, 0.098 ± 0.08 µm with Senso Select and 0.124 ± 0.08 µm with Wohlk contact lens (P-value < 0.0001). The mean RMS (root mean square) for high order aberrations decreased from 0.526 ± 0.43 µm before fitting to 0.256 ± 0.09 µm with Boston, 0.263 ± 0.12 µm with Senso Select, and 0.304 ± 0.10 µm with Wohlk contact lens (P-value= 0.001). The mean RMS for low order aberrations decreased from 1.480 ± 0.78 µm before fitting to 0.703 ± 0.43 µm with Boston, 0.802 ± 0.39 µm with Senso Select, and 0.760 ± 0.45µm with Wohlk (P-value < 0.0001). Despite achieving optimal fit and good visual acuity with these different RGP lenses, in keratoconus patients, their performance is different in reducing ocular aberrations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7739550PMC
December 2020

Topographic properties of the cornea in welders.

Eur J Ophthalmol 2020 Dec 6:1120672120974293. Epub 2020 Dec 6.

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

Purpose: The aim of the present study was to evaluate the topographic status of the welders' corneas.

Methods: In this historical cohort, a group of welders (with at least 5 years' experience in welding) and a control group were assessed and compared. Lack of exposure to welding for 3 months or more was considered an exclusion criterion. In all participants, after taking a complete history of visual and ocular problems, both eyes underwent Pentacam imaging. Then, all subjects received slit lamp biomicroscopy for evaluation of ocular surface diseases.

Results: The data of 140 welders (mean age: 46.66 ± 13.01 years) and 172 controls (mean age: 45.05 ± 12.61 years) were analyzed. The welders' corneas had significantly higher eccentricity ( < 0.0001), keratometry readings ( < 0.0001), and cylinder power ( < 0.0001). The central, inferior, and nasal cornea were significantly thinner in the welders than in controls ( < 0.0001) while the difference was not significant in the superior and temporal cornea. All indices of corneal irregularity except for the central keratoconus index (CKI) and index of height asymmetry (IHA) were higher in welders compared to the control group ( < 0.0001).

Conclusion: According to the results of this study, the welders' corneas are topographically irregular. Welders exhibit characteristics like steeper keratometry readings; higher eccentricity indexes; thinner central, inferior, and nasal corneas; and higher indices of corneal irregularity, especially the CK index. Long-term ultraviolet exposure may be a possible reason for these corneal changes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/1120672120974293DOI Listing
December 2020

Visual Acuity Improvement in Adult Anisometropic Amblyopes After Active Vision Therapy.

Clin Optom (Auckl) 2020 15;12:183-187. Epub 2020 Oct 15.

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

Purpose: The aim of this study is to evaluate the effect of active vision therapy in adults with anisometropic amblyopia.

Methods: In this study, 20 adults with anisometropic amblyopia aged from 17-35 years old were treated for five sessions (one session per week) with vision therapy techniques which include accommodative rock, vergence rock, and saccadic training. Moreover, computerized vision therapy was performed by Optosys software. Also, patients had been given a daily program for home training, including accommodative and vergence rock, and Optosys software. Best corrected visual acuity (BCVA) was measured before and after treatment.

Results: Comparison of data using -test showed that BCVA significantly improved after the vision therapy period. Initial BCVA (Log MAR) was 0.37±0.04 (mean±standard deviation) which improved to 0.14±0.03 after treatment. The correlation between initial BCVA and the amount of improvement showed that the worse the pre-treatment visual acuity was, the greater improvement that occurred.

Conclusion: The improvement of visual acuity in adult anisometropic amblyopes showed that there are some degrees of plasticity in the visual system of amblyopic patients even in adulthood. Thus, therapists should give the chance of treatment to adult amblyopes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2147/OPTO.S250813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7571576PMC
October 2020

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/08820538.2020.1810288DOI Listing
May 2020

Evaluation of Changes in Refractive Errors Before and After Trabeculectomy and Shunt Surgery.

Clin Optom (Auckl) 2020 29;12:107-112. Epub 2020 Jul 29.

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

Purpose: The aim of the present study was to investigate the change rate of astigmatism and axial, myopia, and hypermetropia in trabeculectomy and shunt surgery.

Patients And Methods: In this comparative study, two groups of 16 patients with an average age of 52.4±8.9 and 94.6±6.7 respectively underwent trabeculectomy and shunt surgery. The changes of reactive error were compared before the surgery and 1 week, 1 month, and 3 months after the surgery. Data from the two groups were analyzed via Friedman and Mann-Whitney tests.

Results: Average of intraocular pressure (IOP) before, and 1 week, 1 month, and 3 months after trabeculectomy is 31.31±7.6, 9.8±2.8, 10.5±1.29, 10.9±1.26 (<0.05) and shunt is 36.06±10.32, 13.5±3.3, 11.68±2.21, 11.18±1.27 (<0.05). Average astigmatism in trabeculectomy is -1.00±0.59, -6.00±1.9, -2.21±1.18, -1.37±0.62 (<0.05) and in shunt it is -0.89±0.46, -1.56±1.62, -1.51±1.46, -1.07±0.85 (>0.05). Percent WRT astigmatism in trabeculectomy is 37.5, 100, 37.5, 31.25 and in shunt it is 43.75, 50, 50, 56.25 and average of spherical equivalence (SE) in trabeculectomy is -0.31±1.49, 1.43±1.94, 0.27±1.74, 0.04±1.46 (<0.05) and in shunt it is 0.65±1.5, 1.03±2.03, -0.70±1.64, 0.62±1.54 (<0.05). Astigmatism and axial comparisons between trabeculectomy and shunt with Mann-Whitney test were significant (<0.05), but SE was not significant (>0.05).

Conclusion: The surgeries induced hypermetropia and reduction with the passing of time but astigmatism amount and percent of with-the-rule astigmatism in trabeculectomy were more than in shunt surgery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2147/OPTO.S241659DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7398678PMC
July 2020

The Distribution of Vertical Cup-to-Disc Ratio and its Determinants in the Iranian Adult Population.

J Curr Ophthalmol 2020 Jul-Sep;32(3):226-231. Epub 2020 Jul 4.

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

Purpose: To determine the distribution of vertical cup-to-disc ratio (VCDR) and its relationship with ocular biometric indices.

Methods: This study was conducted in 4737 individuals aged 45-69 years living in Shahroud who participated in the second phase of Shahroud Eye Cohort Study in 2014. All participants underwent eye examinations including the measurement of visual acuity and refraction, slit-lamp biomicroscopy, retinal examination, and fundoscopy. Normality index was used to describe data distribution, and a multiple beta regression, with adjustment for the effect of cluster sampling, was applied to explore the relationship between VCDR and the study variables.

Results: The mean [95% confidence interval (CI)] VCDR was 0.297 (0.293-0.301) in all participants; 0.296 (0.291-0.302) in men and 0.297 (0.292-0.302) in women. The highest mean VCDR was seen in the age group 55-59 years (0.299, 95% CI: 0.292-0.307). The 97.5 percentile was 0.600. According to multiple beta regression analysis, VCDR had a positive association with the female sex ( = 0.028), spherical equivalent ( < 0.001), cigarette smoking ( = 0.020), and axial length ( < 0.001), and had a negative association with hypertension ( = 0.001), best corrected visual acuity ( < 0.001), hyperlipidemia ( = 0.029) and anterior chamber depth ( = 0.001).

Conclusions: The mean VCDR and the 97.5 percentile were lower than most other studies. Although ethnicity and race may play a role in this difference, this difference should be considered in clinical decisions in the current population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.joco.2019.06.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7382515PMC
July 2020

Non-surgical Management Options of Intermittent Exotropia: A Literature Review.

J Curr Ophthalmol 2020 Jul-Sep;32(3):217-225. Epub 2020 Jul 4.

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

Purpose: To review current non-surgical management methods of intermittent exotropia (IXT) which is one of the most common types of childhood-onset exotropia.

Methods: A search strategy was developed using a combination of the words IXT, divergence excess, non-surgical management, observation, overcorrecting minus lens therapy, patch/occlusion therapy, orthoptics/binocular vision therapy, and prism therapy to identify all articles in four electronic databases (PubMed, Web of Science, Google Scholar, and Scopus). To find more articles and to ensure that the databases were thoroughly searched, the reference lists of the selected articles were also reviewed from inception to June 2018 with no restrictions and filters.

Results: IXT is treated when binocular vision is impaired, or the patient is symptomatic. There are different surgical and non-surgical management strategies. Non-surgical treatment of IXT includes patch therapy, prism therapy, orthoptic sessions, and overcorrecting minus lens therapy. The objective of these treatments is to reduce the symptoms and the frequency of manifest deviation by decreasing the angle of deviation or enhancing the ability to control it.

Conclusions: Evidence of the efficacy of non-surgical management options for IXT is not compelling. More comprehensive randomized controlled trial studies are required to evaluate the effectiveness of these procedures and detect the most effective strategy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4103/JOCO.JOCO_81_20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7382517PMC
July 2020

Economic Inequality in Unmet Refractive Error Need in Deprived Rural Population of Iran.

J Curr Ophthalmol 2020 Apr-Jun;32(2):189-194. Epub 2020 Apr 30.

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

Purpose: To determine economic inequality in unmet refractive error (RE) need and its determinants in deprived rural population of Iran.

Methods: In this population-based study, two villages were randomly selected from among underserved villages of Iran. After selecting the participants, optometric examinations, including uncorrected and corrected visual acuity and subjective and manifest refraction, were done for all the participants. Then, unmet need for glasses was determined. Concentration index (C) was used to assess inequality, and Oaxaca-Blinder decomposition method was applied to decompose the gap between the two groups based on the determinants.

Results: Of 3851 samples, 3314 participated in the study (response rate = 86.05%). The data of 3255 participants were used for analysis. The value of C and 95% confidence interval (CI) was -0.088 (-0.157 to -0.020), indicating a pro-poor inequality in unmet need. The prevalence (95% CI) of unmet need was 11.74% (9.25-14.22) in the poor and 6.51% (4.96-8.06) in the rich, with a gap of about 5% in favor of the rich ( < 0.001). A marked percentage of the gap was due to the explained portion (b = 5.73; = 0.031). In the explained portion, the variable of economic status ( = 3.48; = 0.004) and myopia ( = 0.88; = 0.031) caused inequality in favor of the rich and against the poor, respectively. In the unexplained portion ( = -0.51; = 0.372), the variables of education ( = 0.002) and place ( = 0.001) had statistically significant effects on inequality.

Conclusions: There is a significant pro-poor economic inequality in the prevalence of unmet need in rural areas of Iran. Although part of this inequality is related to variables such as education and myopia, a major portion (two thirds) of this inequality may be due to the direct effect of economic inequality.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4103/JOCO.JOCO_100_20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7337026PMC
April 2020

The Prevalence of Ptosis and Nystagmus in Rural Population.

J Curr Ophthalmol 2020 Apr-Jun;32(2):178-182. Epub 2020 Apr 30.

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

Purpose: To determine the prevalence of ptosis and nystagmus in the general rural population in Iran.

Methods: Two villages were selected from the north and southwest of Iran using a multi-stage cluster sampling approach. After selection of the participants and inviting them to a complete eye exam, they all had vision tests and an ophthalmic examination. Vision tests included measurement of visual acuity, refraction, and the cover test. Then the slit-lamp exam was performed, and the diagnosis of ptosis and nystagmus was determined by an ophthalmologist.

Results: Of the 3851 invitees, 3314 people participated in the study. The prevalence of ptosis in this study was 2.23% [95% confidence interval (CI): 1.73-2.74], and 45.3% of the cases were bilateral ptosis. The prevalence of ptosis was lowest in the 21-30 year (0.2%) and the under 5 year (0.8%) age groups, and the highest prevalence was observed in people over 70 years of age (6.7%) ( < 0.001). The prevalence of ptosis was higher in illiterate people than those with an academic education level ( = 0.012). The prevalence of astigmatism was 62.8% in those with ptosis and 34.2% in those without ptosis ( < 0.001). The prevalence of nystagmus was 0.39% (13 cases).

Conclusions: This study found that the prevalence of ptosis is relatively high in the general rural population in Iran, and the prevalence increases with age. Astigmatism is significantly high among cases with ptosis, and its prevalence has an inverse relation with the level of education. Nystagmus also had a high prevalence in this population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.joco.2018.11.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7337018PMC
April 2020

The Effect of Cyclopentolate on Ocular Biometric Components.

Optom Vis Sci 2020 06;97(6):440-447

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

Significance: It is apparent that a variety of biometric changes are caused by different types of cycloplegic eye drops. However, these effects are inconsistent and have not been reported in different refractive groups.

Purpose: The purpose of this study was to determine the effect of cyclopentolate 1% on ocular biometric components in different types of refractive errors in children.

Methods: This cross-sectional study was conducted on 226 eyes of 113 schoolchildren in Shahroud, northeast Iran, with a mean ± standard deviation age of 9.20 ± 1.65 years. All participants had noncycloplegic and cycloplegic objective refraction using an autorefractometer. Cycloplegia was induced using cyclopentolate 1% eye drops. Biometric measurements were made with Allegro Biograph (WaveLight AG, Erlangen, Germany) before and after administering cycloplegic drops. Mixed-effect model regression was used to analyze the data.

Results: After cycloplegia, the vitreous chamber depth (VCD) (-0.043; 95% confidence interval [CI], -0.067 to -0.019 mm), lens thickness (-0.146; 95% CI, -0.175 to -0.117 mm), axial length (-0.009; 95% CI, -0.012 to -0.006 mm), and lens power (-0.335; 95% CI, -0.463 to -0.208 D) decreased significantly, whereas the anterior chamber depth (ACD) (0.183; 95% CI, 0.164 to 0.202 mm), anterior segment length (0.036; 95% CI, 0.014 to 0.058) mm), lens central point (0.109; 95% CI, 0.094 to 0.124 mm), and pupil diameter (1.599; 95% CI, 1.482 to 1.716 mm) increased (P value for all tests, <.001). For changes in VCD and ACD, a significant interaction was observed between different types of refractive errors and cycloplegia, such that the adjusted mean change for ACD was significantly lower and for VCD was significantly higher in hyperopes compared with emmetropes. Lens center moves backward in myopes (0.17 mm) and stays the same in hyperopes under cycloplegia.

Conclusions: According to the findings of this study, cycloplegia reduces the thickness of the crystalline lens and subsequently causes an increase in the ACD. Cycloplegia-related ocular biometric changes were different by type of refractive error.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/OPX.0000000000001524DOI Listing
June 2020

Comparison of Anterior Chamber Depth between Normal and Keratoconic Eyes: A Systematic Review and Meta-Analysis.

J Curr Ophthalmol 2020 Jan-Mar;32(1):94-98. Epub 2020 Mar 23.

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

Purpose: To review the published data about changes in the anterior chamber depth (ACD) in keratoconus patients.

Methods: In this systematic review and meta-analysis of observational studies, we reviewed the available and relevant literature on anterior segment changes in keratoconic eyes, with a special focus on the ACD, an effective factor in many surgical methods. Articles published up to December 2017 were identified in the following data sources: PubMed, Scopus, Ovid, ISI, ScienceDirect, and Google Scholar. Databases were comprehensively searched using the key words "Anterior Chamber Depth AND Anterior segment AND Keratoconus".

Results: A total of 496 studies including these key words were detected. Four hundred fifty-three studies were excluded, and overall 16 studies which precisely described the change in ACD were included in the literature review. The results show that with respect to the applied device, there was a statistically significant difference in ACD between keratoconic eyes and normal eyes except for Galilei analyzer.

Conclusion: Summarizing the results of studies, this review revealed that ACD is significantly deeper in keratoconic eyes as compared with normal eyes, which could be explained by the steeper corneal curvature.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.joco.2019.01.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7265264PMC
March 2020

Prevalence of Refractive Errors in Iranian University Students in Kazerun.

J Curr Ophthalmol 2020 Jan-Mar;32(1):75-81. Epub 2020 Mar 23.

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

Purpose: To determine the prevalence of refractive errors and visual impairment and the correlation between personal characteristics, including age, sex, weight, and height, with different types of refractive errors in a population of university students in the south of Iran.

Methods: In this cross-sectional study, a number of university majors were selected as clusters using multi-stage sampling in all universities located in Kazerun (27 clusters of 133 clusters). Then, proportional to size, a number of students in each major were randomly selected to participate in the study. Uncorrected and corrected visual acuity, non-cycloplegic objective refraction and subjective refraction were measured in all participants.

Results: The prevalence and 95% confidence interval (CI) of presenting visual impairment and blindness was 2.19% (1.48-3.23) and 0.27% (0.12-0.62), respectively. Refractive errors comprised 75% of the causes of visual impairment. The prevalence (95% CI) of myopia [spherical equivalent (SE) ≤ -0.5 D], hyperopia (SE ≥ 0.5 D), and astigmatism (cylinder power < -0.5 D) was 42.71% (39.71-45.77), 3.75% (2.85-4.51), and 29.46% (27.50-31.50), respectively. Totally, 49.03% (46.39-51.68) of the participants had at least one type of refractive error. There was a positive association between weight and myopia (1.01; 95% CI: 1.01-1.02), anisometropia (1.03; 95% CI: 1.01-1.06), and refractive errors (1.01; 95% CI: 1.01-1.02). In comparison with the age group 18-19 years, the odds ratio (OR) of astigmatism in the age group 26-27 years was 1.64 (95% CI: 1.03-2.61), and the OR of anisometropia in the age group ≥ 30 years was 0.21 (95% CI: 0.04-0.98).

Conclusions: The prevalence of refractive errors, especially myopia, is higher in university students than the general population. Since refractive errors constitute a major part of visual impairment, university students should receive special services for providing corrective lenses and glasses to reduce the burden of these disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.joco.2018.08.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7265272PMC
March 2020

Refractive characteristics of keratoconus eyes with corneal Vogt's striae: A contralateral eye study.

J Optom 2021 Apr-Jun;14(2):183-188. Epub 2020 Jun 2.

Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran. Electronic address:

Purpose: The aim of this study was to assess and compare clinical characteristics of bilateral keratoconus patients with unilateral Vogt's striae.

Methods: In this contralateral eye study, refractive status were evaluated in patients with bilateral keratoconus whose corneas had definite slit-lamp biomicroscopic evidence of unilateral Vogt's striae. All cases underwent a comprehensive ophthalmic examination. Some refractive errors components provided by autorefraction were converted to vectorial notation for power vector analysis. Finally, the outcomes were compared between keratoconus eyes with and without Vogt's striae.

Results: Fifty patients aged 20 to 38 years (27.43±5.5) were recruited in this study. The results showed a significant difference in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), non-cycloplegic and cycloplegic autorefraction including sphere, cylinder, spherical equivalent, and J, between keratoconus eyes with and without Vogt's striae (all P<0.05), except for J (P=0.518 in non-cycloplegic autorefraction and P=0.574 in cycloplegic autorefraction). Comparison of cycloplegic and non-cycloplegic autorefraction in both study groups showed significant differences in the sphere and spherical equivalent (all P<0.001), but no significant difference was found in cylinder, J, and J between the study groups (all P>0.05).

Conclusions: Comparison of the cycloplegic and non-cycloplegic autorefraction in keratoconus eyes with and without Vogt's striae showed significant differences in UDVA, CDVA, and some refractive errors components provided by autorefraction between the two groups, with a worse condition in KCN eyes with Vogt's striae.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.optom.2020.04.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8093541PMC
June 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.clae.2020.05.009DOI Listing
June 2021