Publications by authors named "Samira Heydarian"

29 Publications

  • Page 1 of 1

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.
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http://dx.doi.org/10.1016/j.joco.2019.06.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8102948PMC
March 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.
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http://dx.doi.org/10.1080/2576117X.2021.1927291DOI 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

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

Corneal and Ocular Residual Astigmatism in School-Age Children.

J Curr Ophthalmol 2020 Oct-Dec;32(4):355-360. Epub 2020 Dec 12.

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

Purpose: To determine the distribution of residual and corneal astigmatism (CA) in children aged 6-18 years and their relationship with age, sex, spherical equivalent, and biometric parameters.

Methods: In this cross-sectional study, multi-stage stratified cluster sampling was done to select students from Dezful, a city in Southwestern Iran. Examinations included the measurement of visual acuity with and without optical correction, refraction with and without cycloplegia, and biometry using the Biograph (Lenstar, Germany). The main outcomes in this report were corneal and residual astigmatism. The CA was measured by Biograph (difference between k1 and k2), and residual astigmatism was calculated using Alpine method. The power vector method was applied to analyze the data of astigmatism.

Results: Of 864 students that were selected, 683 (79.1%) participated in the study. The mean residual and CA were -0.84 diopter (D) and -0.85 D, respectively. According to the results of J0 and J45 vectors, residual astigmatism was -0.33 D and 0.04 D, and CA was 0.38 D and 0.01 D, respectively. With-the-rule (WTR), against-the-rule (ATR), and oblique astigmatism were seen in 3.4%, 66.8%, and 4.5% of the children with residual astigmatism and 67.94%, 1.3%, and 1.5% of the children with CA. Residual astigmatism decreased with an increase in spherical refractive error, whereas CA increased with an increase in spherical refractive error.

Conclusion: The results of the present study showed a high prevalence and amount of residual astigmatism with ATR pattern among the 6-18-year-old population and the compensatory effect of this type of astigmatism on CA that mostly followed a WTR pattern.
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http://dx.doi.org/10.4103/JOCO.JOCO_8_20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7861098PMC
December 2020

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.
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http://dx.doi.org/10.1016/j.joco.2019.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7861110PMC
December 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.
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http://dx.doi.org/10.4103/JOCO.JOCO_81_20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7382517PMC
July 2020

Reply to: "Agreement analysis".

J Optom 2020 Oct - Dec;13(4):277. Epub 2020 Jun 2.

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

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http://dx.doi.org/10.1016/j.optom.2020.05.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7520515PMC
November 2020

Ocular abnormalities in beta thalassemia patients: prevalence, impact, and management strategies.

Int Ophthalmol 2020 Feb 10;40(2):511-527. Epub 2019 Oct 10.

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

Background: Beta thalassemia (β-thalassemia) is a hereditary disease caused by defective globin synthesis and can be classified into three categories of minor (β-TMi), intermedia (β-TI), and major (β-TM) thalassemia. The aim of our study is to investigate the effects of β-thalassemia and its treatment methods on different parts of the eye and how early-diagnostic methods of ocular complications in this disorder would prevent further ocular complications in these patients by immediate treatment and diet change.

Methods: We developed a search strategy using a combination of the words Beta thalassemia, Ocular abnormalities, Iron overload, chelation therapy to identify all articles from PubMed, Web of Science, Scopus, and Google Scholar up to December 2018. To find more articles and to ensure that databases were thoroughly searched, the reference lists of selected articles were also reviewed.

Results: Complications such as retinopathy, crystalline lens opacification, color vision deficiency, nyctalopia, depressed visual field, reduced visual acuity, reduced contrast sensitivity, amplitude reduction in a-wave and b-wave in Electroretinography (ERG), and decrease in the Arden ratio in Electrooculography (EOG) have all been reported in β-thalassemia patients undergoing chelation therapy.

Conclusion: Ocular problems due to β-thalassemia may be a result of anemia, iron overload in the body tissue, side effects of iron chelators, and the complications of orbital bone marrow expansion.
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http://dx.doi.org/10.1007/s10792-019-01189-3DOI Listing
February 2020

Heritability of pachymetric indices using Pentacam Scheimflug imaging.

Br J Ophthalmol 2020 07 26;104(7):985-988. Epub 2019 Sep 26.

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

Aim: To investigate the heritability of corneal thickness at the apex, entrance pupil centre, thinnest point, pachymetric progression index (PPI) and maximum Ambrósio relational thickness (ART) using Pentacam.

Methods: The present cross-sectional and population-based study was conducted in two rural districts that were selected randomly. Individuals 5 years and older and data from households where one of the parents and at least one child participated in the study were considered for this analysis. All subjects were examined for visual acuity, refraction, biomicroscopy and, finally, Pentacam imaging. The heritability estimate was used to calculate familial aggregation of pachymetric indices.

Results: Of the 3851 selected individuals, 3314 participated in the study. After applying the exclusion criteria, a total of 1383 individuals from 382 households were included in the analysis; of these, 754 (54.52%) were female. The mean age of the subjects was 37.23±19.35 years (from 6 to 93 years). The highest heritability was observed for corneal thickness at the apex (85%), and the lowest was for ART (27.62%). The heritability of other studied parameters, including corneal thickness at the entrance pupil centre, thinnest point and average PPI, was 82.0%, 77.0% and 31.49%, respectively.

Conclusion: The high heritability of the mentioned pachymetric parameters confirms the high correlation between these phenotypes and genetic factors and calls for genetic and molecular research to find related genes and to understand the aetiology of associated diseases, especially glaucoma and keratoconus.
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http://dx.doi.org/10.1136/bjophthalmol-2019-314640DOI Listing
July 2020

The Prevalence and Risk Factors for Keratoconus: A Systematic Review and Meta-Analysis.

Cornea 2020 Feb;39(2):263-270

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

Purpose: This study was conducted to determine the prevalence and risk factors for keratoconus worldwide.

Methods: In this meta-analysis, using a structured search strategy from 2 sources, 4 electronic databases (PubMed, Web of Science, Google Scholar, and Scopus) and the reference lists of the selected articles were searched from inception to June 2018 with no restrictions and filters. The outcome of the study was the prevalence of keratoconus and its risk factors, including eye rubbing, family history of keratoconus, atopy, allergy, asthma, eczema, diabetes type I and type II, and sex.

Results: In this study, 3996 articles were retrieved, of which 29 were analyzed. These 29 articles included 7,158,241 participants from 15 countries. The prevalence of keratoconus in the whole population was 1.38 per 1000 population [95% confidence interval (CI): 1.14-1.62 per 1000]. The prevalence of keratoconus was 20.6 per 1000 (95% CI: 11.68-28.44 per 1000) in men and 18.33 per 1000 (95% CI: 8.66-28.00 per 1000) in women in studies reporting sex. The odds ratio of eye rubbing, family history of keratoconus, allergy, asthma, and eczema was 3.09 (95% CI: 2.17-4.00), 6.42 (95% CI: 2.59-10.24), 1.42 (95% CI: 1.06-1.79), 1.94 (95% CI: 1.30-2.58), and 2.95 (95% CI: 1.30-4.59), respectively.

Conclusions: The results of this study, as the most comprehensive meta-analysis of keratoconus prevalence and risk factors, showed that keratoconus had a low prevalence in the world and eye rubbing, family history of keratoconus, allergy, asthma, and eczema were the most important risk factors for keratoconus according to the available evidence.
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http://dx.doi.org/10.1097/ICO.0000000000002150DOI Listing
February 2020

Agreement between Pentacam and handheld Auto-Refractor/Keratometer for keratometry measurement.

J Optom 2019 Oct - Dec;12(4):232-239. Epub 2019 Jul 10.

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

Objective: This study was conducted to evaluate the level of agreement in keratometry measurements between a rotating Scheimpflug imaging-based system (Pentacam) and a handheld auto-refractokeratometer (handheld NIDEK ARK-30).

Method: This analytical cross-sectional study was conducted in the right eyes of 579 subjects. Keratometry measurements were conducted with the Pentacam and the handheld NIDEK ARK-30 systems. The SPSS Software version 22 and MedCalc V3 were applied to estimate descriptive statistics using paired t-test, Pearson correlation coefficient, 95% limits of agreement (LoA), and Bland-Altman plot.

Results: In the total sample, the inter-device difference in the mean flat and steep keratometry values was -0.266 diopter (D) (P-value<0.001) and 0.052D (P-value=0.093), respectively. There was a significant difference in mean flat keratometry between the two devices in all groups of refractive errors (paired difference <0.5D and P-value<0.001). The difference in mean steep keratometry was significant only in myopic subjects (P-value=0.046). The 95% LoA between the two devices measurements was 2.51D, 3.98D, and 6.37D for flat keratometry and 2.6D, 3.2D, and 3.9D for steep keratometry in emmetropic, myopic, and hyperopic subjects, respectively.

Conclusion: Our study showed relatively wide limits of agreement between handheld NIDEK ARK-30 and Pentacam; therefore, these devices cannot be used interchangeably for measuring corneal curvature.
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http://dx.doi.org/10.1016/j.optom.2019.06.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6978591PMC
May 2020

Distribution of Keratoconus Indices in Normal Children 6 to 12 Years of Age.

Eye Contact Lens 2020 May;46(3):160-165

Noor Research Center for Ophthalmic Epidemiology (H.H.), Noor Eye Hospital, Tehran, Iran; Department of Rehabilitation Sciences (S.H.), School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran; Department of Medical Surgical Nursing (M.K.), School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Ophthalmic Epidemiology Research Center (M.H.E.), Shahroud University of Medical Sciences, Shahroud, Iran; Department of Optometry (A.Y.), School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran; and Department of Epidemiology and Biostatistics (A.F.), School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Objectives: To determine the distribution of keratoconus indices in normal children 6 to 12 years of age.

Methods: This cross-sectional study was conducted in children living in urban and rural areas of Shahroud, northeast Iran in 2015. After careful optometric examinations, the Pentacam was used for corneal imaging and measurement of keratoconus indices.

Results: Of 5,620 students who participated in the study, the data of the right eye of 4,947 children were analyzed after applying the exclusion criteria. The mean age of all children was 9.23±1.71 years (range: 6-12 years). The mean and 95% confidence intervals (in the parentheses) of index of surface variance (ISV), index of vertical asymmetry, keratoconus index (KI), central keratoconus index (CKI), index of height asymmetry, index of height decentration (IHD), and average pachymetric progression index (PPIAve) was 17.770 (17.610-17.930), 0.137 (0.135-0.139), 1.022 (1.022-1.023), 1.010 (1.010-1.010), 3.299 (3.230-3.368), 0.007 (0.007-0.008), and 0.948 (0.943-0.952), respectively. The results of multilevel mixed-effects linear regression analysis showed that ISV, KI, CKI, IHD, and PPIAve were significantly higher in girls. Index of surface variance and CKI were higher in urban students, and PPIAve was higher in rural students. Except for PPIAve, which was increased with increasing age, the mean values of other keratoconus indices were significantly lower in 12-year-old students compared with 6-year-old ones.

Conclusion: The results provide valuable information about normal distribution of keratoconus indices in children aged 6 to 12 years. These findings can be used in future research and detection of abnormal cases in the clinical setting.
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http://dx.doi.org/10.1097/ICL.0000000000000622DOI Listing
May 2020

Global and regional prevalence of strabismus: a comprehensive systematic review and meta-analysis.

Strabismus 2019 06 23;27(2):54-65. Epub 2019 Apr 23.

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

: Despite the importance of information on the prevalence of strabismus, which can be effective in planning preventive and curative services, no study has addressed its prevalence comprehensively. In this study, a systematic search was done to estimate the regional and global prevalence of strabismus in different age and sex groups and factors affecting prevalence heterogeneity. : A comprehensive and systematic search was done in different international databases, including Web of Science, Scopus, PubMed, Embase, etc. to find published articles on the total prevalence of strabismus and the prevalence of exotropia and esotropia. A binomial distribution was used to calculate the prevalence and 95% confidence interval (CI). The Cochran's Q-test and I were applied to evaluate heterogeneity and a random-effects model was used to assess the pooled prevalence. The Begg's test was administered to investigate publication bias and finally, a meta-regression method was applied to determine the factors affecting the heterogeneity among studies. : Of 7980 articles, 56 articles with a total sample size of 229,396 were analyzed. Many of these articles (n = 14) were from the Regional Office for the Americas. The estimated of pooled prevalence (95% CI) of any strabismus, exotropia, and esotropia was 1.93% (1.64-2.21), 1.23% (1.00-1.46), and 0.77% (0.59-0.95), respectively. The heterogeneity in prevalence of strabismus and its subtypes according to I was above 95% (p value <.001 for all). Age had a direct effect on heterogeneity in the prevalence of exotropia (b: 3.491; p: 0.002). Moreover, WHO region had a significant direct effect on heterogeneity in the prevalence of strabismus (b: 0.482; p < .001) and esotropia (b: 0.168; p: 0.027), and publication year had a significant direct effect on heterogeneity in the prevalence of exotropia (b: 0.059; p: 0.045). Sample size and publication year did not have any association with strabismus nor with other variables. There was no publication bias according to the Begg's test. : The prevalence of strabismus varies widely in the world. As for factors affecting heterogeneity in the prevalence of strabismus, the results showed that age affected heterogeneity in the prevalence of exotropia, WHO region affected heterogeneity in the prevalence of strabismus and esotropia, and publication year affected heterogeneity in the prevalence of exotropia. Information about the global prevalence of strabismus can help health care planners design interventions and prioritize resource allocation.
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http://dx.doi.org/10.1080/09273972.2019.1604773DOI Listing
June 2019

Keratometry in children: Comparison between auto-refractokeratometer, rotating scheimpflug imaging, and biograph.

J Optom 2019 Apr - Jun;12(2):99-110. Epub 2019 Mar 14.

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

Purpose: To determine the agreement and validity of keratometric measurements in children with the Nidek ARK-510A auto-refractokeratometer compared to rotating Scheimpflug imaging with Pentacam and biograph with Lenstar LS 900.

Methods: This study was conducted on 5620 schoolchildren aged 6-12 years in Shahroud, Iran. Minimum and maximum keratometry values and corneal astigmatism magnitude were compared by calculation of Paired difference, interclass correlation coefficient, and 95% limits of agreement (LoA) between devices.

Results: After applying the exclusion criteria, 4215 right eyes were enrolled into the study. Mean minimum keratometry with Nidek ARK-510A, Pentacam, and Lenstar was 43.13±1.51, 43.14±1.48, and 42.87±1.46 diopters (D), respectively, and mean maximum keratometry was 43.97±1.59, 44.00±1.56, and 43.75±1.54D, respectively. Nidek ARK-510A overestimated minimum and maximum keratometry by 0.25±0.37 and 0.22±0.41, respectively, compared to Penatcam. The LoA between Nidek ARK-510A and Pentacam for minimum and maximum keratometry measurements were -0.98 to 0.47D and -1.02 to 0.57D, respectively. The LoA between Nidek ARK-510A and Lenstar for minimum and maximum keratometry measurements were -0.70 to 0.72D and -0.79 to 0.85D, respectively. The agreement between devices was best in emmetropes, worst in hyperopes. For astigmatic vector components, the agreements between devices were poor but best agreement was between Nidek ARK-510A and Pentacam.

Conclusions: Keratometry measurement with Nidek ARK-510A was not significantly different from Pentacam and Lenstar, and this device can be used in screening programs in emmetropes.
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http://dx.doi.org/10.1016/j.optom.2018.12.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6449769PMC
April 2019

Heritability of Corneal Curvature and Pentacam Topometric Indices: A Population-Based Study.

Eye Contact Lens 2019 Nov;45(6):365-371

Department of Rehabilitation Sciences (S.H.), School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran; Noor Research Center for Ophthalmic Epidemiology (H.H.), Noor Eye Hospital, Tehran, Iran; Refractive Errors Research Center (A.Y., H.O.), Mashhad University of Medical Sciences, Mashhad, Iran; Khatam-al-Anbia Hospital (A.D.), Mashhad University of Medical Sciences, Mashhad, Iran; Eye Research Center (M.A.), Tehran University of Medical Sciences, Tehran, Iran; and Department of Medical Surgical Nursing (M.K.), School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Purpose: To investigate familial aggregation of anterior and posterior corneal curvature, corneal astigmatism, and some corneal topometric indices using the Pentacam.

Methods: Of 3,851 eligible individuals who resided in the selected areas, 2,779 met the conditions for analysis. However, analysis was limited to families whose Pentacam measures were available for at least 2 family members (father or mother and a child), resulting in 1,383 individuals in 382 families. All selected subjects underwent a set of examinations, including refraction, uncorrected and corrected visual acuity measurement, slitlamp biomicroscopy, and Pentacam imaging. Heritability estimation was used to calculate familial aggregation.

Results: The results of our study showed a fairly high corneal curvature heritability. The heritability of K2 and K1 in the anterior surface was 58.61% (95% confidence interval [CI], 54.99-62.23) and 55.82% (95% CI, 52.66-58.98), respectively. The heritability of posterior corneal curvature was slightly higher than that of the anterior corneal curvature. The heritability of K2 and K1 in the posterior surface was 63.42% (95% CI, 60.07-66.77) and 59.67% (95% CI, 55.85-63.49), respectively. Investigation of the quantitative topographic corneal indices showed that index of surface variance (ISV), central keratoconus index, and index of vertical asymmetry (IVA) had the highest levels of heritability (81.2% [95% CI, 73.64-88.76], 75.21% [95% CI, 67.19-82.28], and 66.46% [95% CI, 61.99-70.93], respectively). However, keratometric power deviation and index of height asymmetry had the lowest heritability levels (7.48% 95% CI, [4.94-10.02] and 18.31% [95% CI, 16.07-20.55], respectively).

Conclusion: The familial aggregation and relatively high heritability of the corneal curvature and some keratoconus-related indices, such as ISV and IVA, confirm a high correlation between these phenotypes and genetic factors and warrant further investigation of the genetic mechanisms in keratoconus.
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http://dx.doi.org/10.1097/ICL.0000000000000589DOI Listing
November 2019

Heritability of Anterior Chamber Indices in Rural Population.

J Glaucoma 2018 12;27(12):1165-1168

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

Objective: To examine the heritability of the anterior chamber depth, angle, and volume as well as the corneal volume and diameter using Pentacam in households living in underserved rural areas of Iran.

Materials And Methods: This cross-sectional population-based study was conducted in randomly selected households living in 2 rural districts in the south and north. The data of subjects above 5 years and households in which at least 2 members (father or mother and a child) had Pentacam data were analyzed. Each subject underwent a comprehensive ophthalmic examination, with emphasis on the measurement of visual acuity and refraction, biomicroscopy, and Pentacam imaging. Heritability was estimated to investigate familial aggregation of anterior chamber indices, and the effects of age, sex, and living area were controlled for as confounding factors.

Results: Of the 3851 selected individuals, 3314 participated in the study. After applying the exclusion criteria, the data of 1383 subjects from 382 households were included in the analysis. The mean age of the participants was 37.23±19.35 years (range, 6 to 93 y). The highest and lowest heritability estimates were related to the anterior chamber angle (72%) and corneal diameter (28%), respectively. The heritability percentages of the anterior chamber depth, anterior chamber volume, and corneal volume were 47%, 39%, and 57%, respectively.

Conclusions: The high heritability of the anterior chamber angle points to a high correlation between this phenotype and genetic factors. Further genetic and molecular investigations are suggested to find the related genes and understand the etiology of glaucoma.
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http://dx.doi.org/10.1097/IJG.0000000000001085DOI Listing
December 2018

Global and regional estimates of prevalence of amblyopia: A systematic review and meta-analysis.

Strabismus 2018 12 30;26(4):168-183. Epub 2018 Jul 30.

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

: Amblyopia is one of the most important causes of vision impairment in the world, especially in children. Although its prevalence varies in different parts of the world, no study has evaluated its prevalence in different geographical regions comprehensively. The aim of the present study was to provide global and regional estimates of the prevalence of amblyopia in different age groups via a systematic search.: In this study, international databases, including Embase, Scopus, PubMed, Web of Science, and other relevant databases, were searched systematically to find articles on the prevalence of amblyopia in different age groups published in English. The prevalence and 95% CI were calculated using binomial distribution. The Cochran's -test and statistic were applied to assess heterogeneity, a random-effects model was used to estimate the pooled prevalence, and a meta-regression method was utilized to investigate the factors affecting heterogeneity between studies.: Of 1252 studies, 73 studies were included in the analysis (sample volume: 530,252). Most of these studies ( = 25) were conducted in the WHO-Western Pacific Regional Office. The pooled prevalence estimate of amblyopia was 1.75% (95% CI: 1.62-1.88), with the highest estimate in European Regional Office (3.67%, 95% CI: 2.89-4.45) and the lowest in African Regional Office (0.51%, 95% CI: 0.24-0.78). The most common cause of amblyopia was anisometropia (61.64%). The heterogeneity was 98% ( < 0.001). According to the results of univariate meta-regression, the variables of WHO region (: 0.566,  < 0.001), sample size (: -0.284 × 10, : 0.025), and criteria for definition of amblyopia (: -0.292, : 0.010) had a significant effect on heterogeneity between studies, while age group, publication date, and cause of amblyopia had no significant effect on heterogeneity.: The prevalence of amblyopia varies in different parts of the world, with the highest prevalence in European countries. Geographical location and criteria for definition of amblyopia are among factors contributing to the difference across the world. The results of this study can help stakeholders to design health programs, especially health interventions and amblyopia screening programs.
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http://dx.doi.org/10.1080/09273972.2018.1500618DOI Listing
December 2018

The normal distribution of corneal eccentricity and its determinants in two rural areas of north and south of Iran.

J Curr Ophthalmol 2018 Jun 6;30(2):147-151. Epub 2017 Dec 6.

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

Purpose: The aim of this study was to determine the distribution of corneal eccentricity (E-value) in a normal population and to examine related factors.

Methods: In this cross-sectional study, two villages were selected in Iran using multistage cluster sampling. Selected persons were invited to have a comprehensive eye examination. Examinations in each village were performed at a specific location under standard conditions. After testing for vision and refraction and conducting the slit-lamp exam, E-value was measured with Pentacam.

Results: Of the 3851 selected individuals, 3314 participated in the study. After applying the exclusion criteria, data from 2610 subjects was used in the analysis for this report. Mean E-value was 0.53 [95% confidence interval (CI): 0.52 to 0.54]. E-value was not significantly different between males and females. Mean E-value reduced with age from 0.60 in subjects aged 6-20 years to 0.47 in subjects older than 70 years. The hyperopic group of participants had significantly lower E-value than myopic and emmetropic ones ( < 0.001). The relationship of E-value with age, gender, and other anterior segment variables and spherical equivalent was examined in a multiple linear regression model. In multiple linear regression model, age (coef = -0.003), spherical equivalent refraction (coef = -0.005), pupil diameter (coef = 0.018), anterior chamber volume (coef = -0.001), and anterior chamber angle (coef = 0.003) significantly correlated with E-value.

Conclusions: The results of this study showed that the cornea in normal populations is prolate, and the degree of prolateness varies by age, such that older age is associated with a less prolate cornea. This study showed that factors such as age and refractive errors and anterior chamber indices influence the E-value.
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http://dx.doi.org/10.1016/j.joco.2017.11.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033779PMC
June 2018

High prevalence and familial aggregation of keratoconus in an Iranian rural population: a population-based study.

Ophthalmic Physiol Opt 2018 07 24;38(4):447-455. Epub 2018 Mar 24.

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

Purpose: The objective of this study was to determine the prevalence of keratoconus and the potential effect of genetic and environmental factors on its prevalence in households living in rural areas of Iran in a large population-based study.

Methods: The present cross-sectional study was performed in two Iranian rural populations. Two rural areas were randomly selected in the southwest and north of Iran. All individuals over one year of age were invited to participate in the study. The study population underwent a thorough eye examination, including visual acuity measurement, refraction, slit lamp biomicroscopy, and Scheimpflug imaging. The diagnosis of keratoconus was made based on Pentacam-specific criteria, tomographic maps, and clinical findings. After detecting keratoconus cases, its prevalence in the study population was reported as a percentage with a 95% confidence interval (CI). For familial aggregation analysis, the odds ratios of keratoconus and its more severe types were calculated in different family relationships (siblings, parents-offspring, spouses) using second order generalised estimating equation.

Results: Of the 3851 eligible individuals, 3314 subjects participated in the study. After applying the exclusion criteria, data from 2667 subjects was used in the analysis. The prevalence of keratoconus in the present population was 4% (95% CI: 3-4). The odds of keratoconus were significantly higher in males (OR = 2.30, p = 0.032). To investigate the familial aggregation of keratoconus, we only evaluated families from which at least two members participated in the study. So, 403 families (1452 participants) were evaluated. Our results showed a higher odds ratio for the sibling pairs compare to parent-offspring pairs and as reported, the odds ratio of the spouses was less than 1.0.

Conclusion: Our findings showed a relatively high prevalence and familial aggregation of keratoconus in rural areas of Iran, independent of age, sex, and place of residence. This aggregation may be due to heredity or the effect of undetermined shared environmental factors.
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http://dx.doi.org/10.1111/opo.12448DOI Listing
July 2018

Comparison of contrast sensitivity in β-thalassemia patients treated by deferoxamine or deferasirox.

J Optom 2019 Jul - Sep;12(3):168-173. Epub 2018 Mar 10.

Thalassemia Research Center, Mazandaran University of Medical Sciences, Sari, Iran.

Purpose: To compare contrast sensitivity (CS) in multi-transfused β-thalassemia patients who received deferoxamine with those who received Osveral.

Methods: In this cross sectional study a total of 60 β-thalassemia patients (30 used deferoxamine and 30 used deferasirox) were regarded as case group and 30 age and sex matched healthy subjects were selected as control group. All subjects had a set of examinations including refraction, visual acuity, Biomicroscopy, ophthalmoscopy and CS. Contrast threshold was assessed with the use of Freiberg visual acuity and contrast test under the mesopic light condition for three frequencies; 1, 5, 15cpd. All data analysis was performed using SPSS, version 17.

Results: In visual acuity tests, thalassemic patients did not have any problem. Contrast threshold was higher in thalassemic patients who infuse deferoxamine (1.87±0.63, 1.46±0.81, and 2.96±1.68 in 1, 5, and 15cpd, respectively) than that of those who intake deferasirox (1.74±0.80 (P=0.743), 0.99±0.74 (P=0.047), and 2.42±1.36 (P=0.321) for 1, 5, and 15cpd, respectively), and also than healthy patients (1.33±0.58 (P=0.009), 0.95±0.68 (P=0.022), and 2.24±1.23 (P=0.135) for 1, 5, and 15cpd, respectively). Comparing those who used deferasirox with healthy subjects, contrast threshold was higher in deferasirox group at all special frequencies (P>0.05). No significant relationship was observed between CS values and duration of transfusion, serum ferritin concentration and dose of chelation therapy (P>0.05).

Conclusions: CS tests can detect visual disturbance in thalassemic patients before the impairment of visual acuity. It is suggested that CS tests be included in their regular eye examination.
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http://dx.doi.org/10.1016/j.optom.2018.01.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6612051PMC
July 2019

The prevalence of uncorrected refractive errors in underserved rural areas.

J Curr Ophthalmol 2017 Dec 10;29(4):305-309. Epub 2017 Mar 10.

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

Purpose: To determine the prevalence of uncorrected refractive errors, need for spectacles, and the determinants of unmet need in underserved rural areas of Iran.

Methods: In a cross-sectional study, multistage cluster sampling was done in 2 underserved rural areas of Iran. Then, all subjects underwent vision testing and ophthalmic examinations including the measurement of uncorrected visual acuity (UCVA), best corrected visual acuity, visual acuity with current spectacles, auto-refraction, retinoscopy, and subjective refraction. Need for spectacles was defined as UCVA worse than 20/40 in the better eye that could be corrected to better than 20/40 with suitable spectacles.

Results: Of the 3851 selected individuals, 3314 participated in the study. Among participants, 18.94% [95% confidence intervals (CI): 13.48-24.39] needed spectacles and 11.23% (95% CI: 7.57-14.89) had an unmet need. The prevalence of need for spectacles was 46.8% and 23.8% in myopic and hyperopic participants, respectively. The prevalence of unmet need was 27% in myopic, 15.8% in hyperopic, and 25.46% in astigmatic participants. Multiple logistic regression showed that education and type of refractive errors were associated with uncorrected refractive errors; the odds of uncorrected refractive errors were highest in illiterate participants, and the odds of unmet need were 12.13, 5.1, and 4.92 times higher in myopic, hyperopic and astigmatic participants as compared with emmetropic individuals.

Conclusion: The prevalence of uncorrected refractive errors was rather high in our study. Since rural areas have less access to health care facilities, special attention to the correction of refractive errors in these areas, especially with inexpensive methods like spectacles, can prevent a major proportion of visual impairment.
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http://dx.doi.org/10.1016/j.joco.2017.02.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5735237PMC
December 2017

The burden of pure anisometropic amblyopia: a cross-sectional study on 2800 Iranians.

Int Ophthalmol 2018 Feb 13;38(1):29-34. Epub 2017 Dec 13.

Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.

Purpose: To assess the proportion of pure anisometropic amblyopia in a sample Iranian (white) population.

Methods: A total of 2800 consecutive individuals who presented at a referral eye clinic for any reason were examined for the presence of pure anisometropic amblyopia. Anisometropia was reported when a spherical equivalent refraction difference of at least 1.0 D with or without a cylinder refraction difference of at least 1.0 D was present between the two eyes. Amblyopia was defined as the best-corrected visual acuity of 20/30 or worse or a two-line interocular visual acuity difference between eyes that could not be attributed to any structural ocular pathology or visual pathway abnormality.

Results: Subjects were 1528 females and 1272 males with a mean age of 30.25 ± 14.93 years (range, 5-65). Amblyopia was diagnosed in 192 cases (6.9%), significantly more frequent among females (7.9 vs. 5.7%, p = 0.02). Pure anisometropic amblyopia was present in 6.1% of the study population, significantly more common in patients with spherical hyperopic anisometropia (37.7%) compared to patients with spherical myopic anisometropia (21.3%), cylindrical myopic anisometropia (4.1%), and cylindrical hyperopic anisometropia (15%) (p < 0.001).

Conclusions: Pure anisometropic amblyopia is a common finding in Caucasians seeking eye care, particularly when anisometropia is of spherical hyperopic subtype.
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http://dx.doi.org/10.1007/s10792-017-0784-zDOI Listing
February 2018

Tear Deformation Time and optical quality in eyes wearing silicone hydrogel contact lenses.

J Curr Ophthalmol 2016 Dec 25;28(4):226-227. Epub 2016 Jul 25.

Department of Epidemiology & Research Methodology, Faculty of Health, Mashhad University of Medical Sciences, Mashhad, Iran.

Purpose: To evaluate tear film stability and optical aberrations in eyes wearing plano Lotrafilcon B contact lenses (CL).

Methods: Tear Deformation Time (TDT) and aberrometric parameters were assessed in 86 normal emmetropic eyes before and 6 h after wearing CL.

Result: A statistically significant decrease in TDT and increase in root mean square (RMS) values of higher order aberrations (HOA) were revealed 6 h after CL insertion (both P < 0.001). The low order aberrations (LOA) RMS values measured with CL were higher than those in naked eyes, but the difference was not statistically significant. None of individual Zernike polynomials showed any significant alteration.

Conclusion: Our findings indicated that the Lotrafilcon B contact lens affects HOA more than LOA. The tear film was less stable after wearing CL.
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http://dx.doi.org/10.1016/j.joco.2016.07.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5093784PMC
December 2016

Prevalence of color vision deficiency among arc welders.

J Optom 2017 Apr - Jun;10(2):130-134. Epub 2016 Mar 15.

Ahvaz, Iran.

Purpose: This study was performed to investigate whether occupationally related color vision deficiency can occur from welding.

Methods: A total of 50 male welders, who had been working as welders for at least 4 years, were randomly selected as case group, and 50 age matched non-welder men, who lived in the same area, were regarded as control group. Color vision was assessed using the Lanthony desatured panel D-15 test. The test was performed under the daylight fluorescent lamp with a spectral distribution of energy with a color temperature of 6500K and a color rendering index of 94 that provided 1000lx on the work plane. The test was carried out monocularly and no time limit was imposed. All data analysis were performed using SPSS, version 22.

Results: The prevalence of dyschromatopsia among welders was 15% which was statistically higher than that of nonwelder group (2%) (p=0.001). Among welders with dyschromatopsia, color vision deficiency in 72.7% of cases was monocular. There was positive relationship between the employment length and color vision loss (p=0.04). Similarly, a significant correlation was found between the prevalence of color vision deficiency and average working hours of welding a day (p=0.025).

Conclusions: Chronic exposure to welding light may cause color vision deficiency. The damage depends on the exposure duration and the length of their employment as welders.
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http://dx.doi.org/10.1016/j.optom.2015.12.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5383458PMC
April 2017

Refractive errors and ocular biometry components in thalassemia major patients.

Int Ophthalmol 2016 Apr 8;36(2):267-71. Epub 2015 Dec 8.

Thalassemia Research Center, Mazandaran University of Medical Sciences, Sari, Iran.

The aim of this study is to determine and compare biometric and refractive characteristics of thalassemia major patients and normal individuals. In this cross-sectional study, 54 thalassemia major patients were selected randomly as case group, and 54 age- and sex-matched healthy subjects were regarded as control group. Refractive errors, corneal curvature and ocular components were measured by autokeratorefractometery and A-scan ultrasonography, respectively. Mean spherical equivalent was -0.0093 ± 0.86 D in thalassemia patients and -0.22 ± 1.33 D in the normal group. The prevalence of myopia, Hyperopia, and emmetropia among thalassemia patients was 16.7, 19.4, and 63.9 %, respectively. While in the control group, 26.9 % were myopic, 25 % were hyperopic, and 48.1 % were emmetropic. The prevalence of astigmatism in case group was 22.2 %, which was not significantly different from that in control group, (27.8 %, p = 0.346). Mean axial length in thalassemia patients was 22.89 ± 0.70 which was significantly lower than that in normal group (23.37 ± 0.91, p = 0.000). The flattest meridian of the cornea (R1) was significantly steeper in thalassemia patients (7.77 ± 0.24) in comparison to normal individuals (7.85 ± 0.28). Although thalassemic patients had significantly smaller axial length and vitreous chamber depth in comparison to normal group, which could be due to their abnormal physical growth, there was no significant difference between the mean of spherical equivalent among two groups. This can be due to their steeper corneal curvature that overcomes the refractive disadvantage of their shorter axial length.
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http://dx.doi.org/10.1007/s10792-015-0161-8DOI Listing
April 2016

Ocular abnormalities in multi-transfused beta-thalassemia patients.

Indian J Ophthalmol 2015 Sep;63(9):710-5

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

Aims: The aim of this study was to assess ocular changes in thalassemia patients who have received multiple transfusions and chelate binding therapy in order to avoid iron accumulation.

Settings And Design: A cross-sectional study.

Subjects And Methods: A total of 54 thalassemia major patients were selected as case group, and 54 age- and sex-matched healthy subjects were regarded as a control group. Ocular examination included visual acuity, refraction testing, slit lamp examination, funduscopy, tonometry, perimetry, tear break-up time test, and color vision testing were performed for all the participants. We computed the frequency and duration of blood transfusion, the mean serum ferritin level, pretransfusion hemoglobin concentration, and type, duration, and daily dose of chelation therapy for thalassemia patients based on their records.

Statistical Analysis Used: All data analysis was performed using SPSS, version 19.

Results: All the thalassemic patients were asymptomatic, but abnormal ocular findings (dry eye (33.3%), cataract (10.2%), retinal pigment epithelium degeneration (16.7%), color vision deficiency (3.7%), and visual field defects (33.7%)) were seen in 68.5% of thalassemic group. The prevalence of ocular abnormalities in normal group was 19.4%, which was significantly lower than that in thalassemia patients (P = 0.000). No significant correlation was found between ocular abnormalities and mean serum ferritin level (P = 0.627) and mean hemoglobin concentration (P = 0.143). Correlation of number of blood transfusion with the presence of ocular abnormalities was found to be statistically significant (P = 0.005).

Conclusions: As life expectancy for beta-thalassemia patients extends, regular ophthalmological evaluation to detect early changes in their ocular system is recommended.
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http://dx.doi.org/10.4103/0301-4738.170986DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4705706PMC
September 2015

Effect of yellow filter on visual acuity and contrast sensitivity under glare condition among different age groups.

Int Ophthalmol 2016 Aug 27;36(4):509-14. Epub 2015 Nov 27.

AL Zahra Eye Hospital, Zahedan University of Medical Science, Zahedan, Iran.

The aim of this study is to investigate the effect of yellow filter on visual acuity and contrast sensitivity under glare condition for various ages. A total of 60 subjects, aged 5-60 years, with no ocular pathology and no previous surgery were assessed in this cross-sectional study. We divided subjects into six subgroups according to their ages, and the number of subjects in each group was 10: group 1, aged 5-10 years; group 2, aged 11-20 years; group 3, aged 21-30 years; group 4, aged 31-40 years; group 5, aged 41-50 years; and group 6, aged 51-60 years. Snellen visual acuity and Pelli Robson contrast sensitivity with and without glare and with the use of yellow filter under glare condition were determined. Data analysis was carried out using SPSS, version 20. Our results showed a significant reduction in contrast sensitivity under glare condition in all age groups (p = 0.000), which improved significantly with the use of yellow filter (p = 0.000). Although when data in different age groups were analyzed separately, this improvement was only significant in older subjects, aged 51-60 years (p = 0.007). No significant difference was found between Snellen visual acuity with and without glare (p = 0.083), and also we found no yellow filter effect on visual acuity under glare condition. We conclude that yellow filter, which absorbs short wavelength, may provide significant contrast sensitivity benefits for individuals and influences older subjects more than younger ones.
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http://dx.doi.org/10.1007/s10792-015-0154-7DOI Listing
August 2016

Quality of sunglasses available in the Iranian market; a study with emphasis on sellers' license.

Indian J Ophthalmol 2015 Feb;63(2):152-6

Department of Ophthalmology, Farshchian Educational and Medical Center, Hamadan University of Medical Sciences, Hamadan, Iran.

Context: Sunglasses should follow minimum requirements to sufficiently protect eyes. It is not known whether all items obtainable from the market are appropriately designed.

Aims: To compare ultraviolet (UV)-protective properties of commercially available sunglasses obtained from authorized and unauthorized Iranian sellers. Settings and Study Design: An analytic-descriptive study performed in a metropolitan area (Tehran).

Materials And Methods: Using a UV-visible standard spectrophotometer, the percentage transmittance was scanned between 280 and 400 nm in 348 pairs of nonprescription sunglasses (price range: 20-80 US$) obtained anonymously and randomly from authorized (permitted by the Ministry of Health, 189 pairs) and unauthorized (159 pairs) sellers in the Iranian capital city, Tehran. The Australian/New Zealand Standard (AS/NZS) and the American National Standards Institute [ANSI] standards were followed.

Statistical Analysis: Chi-square test, independent samples t-test or Mann-Whitney U-test. Results UV-protective properties of the sunglasses obtained from authorized sellers complied with AS/NZS and ANSI guidelines in 92.6% and 95.2% of items, respectively. The corresponding rates for sunglasses obtained from unauthorized sellers were 0% and 8.2%, respectively (P < 0.001 for both). The rate of defective polarizing capability of lenses was 27.4% in sunglasses obtained from authorized sellers versus 90.4% in sunglasses obtained from unauthorized sellers (P < 0.001). Neither brand nor price played significant contributions to UV protection/lens polarizing capability of sunglasses obtained from authorized sellers.

Conclusions: Sunglasses provided by unauthorized sellers are alarmingly unreliable and could be potentially hazardous for the eye. Brand and price do not guarantee optimal protection against UV radiation or polarizing performance of the lens.
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http://dx.doi.org/10.4103/0301-4738.154395DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4399125PMC
February 2015