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Purpose: To determine economic inequality in visual impairment (VI) and its determinants in the rural population of Iran., Methods: In this population-based, cross-sectional study, 3850 individuals, aged 3-93 years were selected from the north and southwest regions of Iran using multi-staged stratified cluster random sampling. The outcome was VI, measured in 20 feet. Economic status was constructed using principal component analysis on home assets. The concentration index ( C ) was used to determine inequality, and the gap between low and high economic groups was decomposed to explained and unexplained portions using the Oaxaca-Blinder decomposition method., Results: Of the 3850 individuals that were invited, 3314 participated in the study. The data of 3095 participants were finally analyzed. The C was -0.248 (95% confidence interval [CI]: -0.347 - -0.148), indicating a pro-poor inequality (concentration of VI in low economic group). The prevalence (95% CI) of VI was 1.72% (0.92-2.52) in the high economic group and 10.66% (8.84-12.48) in the low economic group with a gap of 8.94% (6.95-10.93) between the two groups. The explained and unexplained portions comprised 67.22% and 32.77% of the gap, respectively. Among the study variables, age (13.98%) and economic status (80.70%) were significant determinants of inequality in the explained portion. The variables of education (coefficient: -4.41; P < 0.001), age (coefficient: 14.09; P < 0.001), living place (coefficient: 6.96; P : 0.006), and economic status (coefficient: -7.37; P < 0.001) had significant effects on inequality in the unexplained portion., Conclusions: The result showed that VI had a higher concentration in the low economic group, and the major contributor of this inequality was economic status. Therefore, policymakers should formulate appropriate interventions to improve the economic status and alleviate economic inequality., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 Journal of Current Ophthalmology.)

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 f ), keratometry-steep (K s ), keratoconus index (KI), and central keratoconus index (CKI)., Results: The mean ± standard deviation of K f , K s , 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, P < 0.001), index vertical asymmetry (IVA) (b: -0.012, P < 0.001), KI (b: -0.011, P < 0.001), CKI (b: -0.001, P < 0.001), index height asymmetry (IHA) (b: -0.491, P: 0.005), and index height decentration (IHD) (b: -0.001, P < 0.001) were lower in men compared to women. Moreover, age had an indirect association with ISV (b: -0.030, P < 0.001) and average pachymetric progression index (RPI&#95;avg) (b: -0.001, P < 0.001), and a direct association with KI, CKI, and IHA. Spherical equivalence had an indirect association with KI (b: -0.001, P < 0.001) and RPI&#95;avg (b: -0.004, P < 0.001) and a direct association with CKI (b: 0.001, P < 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., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Journal of Current Ophthalmology.)

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 th percentile was 0.600. According to multiple beta regression analysis, VCDR had a positive association with the female sex ( P = 0.028), spherical equivalent ( P < 0.001), cigarette smoking ( P = 0.020), and axial length ( P < 0.001), and had a negative association with hypertension ( P = 0.001), best corrected visual acuity ( P < 0.001), hyperlipidemia ( P = 0.029) and anterior chamber depth ( P = 0.001)., Conclusions: The mean VCDR and the 97.5 th 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., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Journal of Current Ophthalmology.)

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 ( P < 0.001). A marked percentage of the gap was due to the explained portion (b = 5.73; P = 0.031). In the explained portion, the variable of economic status ( b = 3.48; P = 0.004) and myopia ( b = 0.88; P = 0.031) caused inequality in favor of the rich and against the poor, respectively. In the unexplained portion ( b = -0.51; P = 0.372), the variables of education ( P = 0.002) and place ( P = 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., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Journal of Current Ophthalmology.)

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., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Journal of Current Ophthalmology.)

Purpose: To determine the distribution of iris color and its relationship with some ocular diseases in a rural population of Iran., Methods: Two rural areas of the north and southwest of Iran were selected by a cross-sectional study using multi-stage cluster sampling. After selecting samples, the participants had an eye examination including measuring visual acuity, refraction, and Pentacam imaging. Then an eye examination for individuals was performed by slit-lamp., Results: Out of 3851 invited people, 3314 participated in this study (participation rate, 86.05%). Dark brown [41.28%, confidence interval (CI) 95% = 31.88-50.68] and blue (0.99%, CI 95% = 0.57-1.41) were the most and the least type of iris colors among participants of this study. Compared to others, people with a dark iris have the biggest anterior chamber depth (ACD), angle and volume while central corneal thickness (CCT), keratometry and pupil were highest among people with a dark brown iris ( P  < 0.002). Considering the dark brown group as a base group, the chances of being afflicted to cataract among people with dark, light brown, green, and blue irises are 1.89 (CI 95% = 1.25-2.86), 1.53 (CI 95% = 1.17-2.01), 4.60 (CI 95% = 2.17-9.71), and 12.17 (CI 95% = 5.05-29.31), respectively. The chance of being afflicted to myopia among people with green irises and to hyperopia among people with blue irises were high (1.60, CI 95% = 1.08-2.36 and 3.20, CI 95% = 1.03-9.97, respectively)., Conclusions: Dark brown was the most prevalent iris color in rural areas of Iran. The index of cornea among people with dark and dark brown iris color is higher than other people, and people with light iris color are at a higher risk of developing eye disease such as cataract, corneal opacity, and refractive error. To determine this relationship and its usage for therapeutic and public health purposes, further studies are recommended.

Purpose: The aim of the study was a systematic review of refractive errors across the world according to the WHO regions., Methods: To extract articles on the prevalence of refractive errors for this meta-analysis, international databases were searched from 1990 to 2016. The results of the retrieved studies were merged using a random effect model and reported as estimated pool prevalence (EPP) with 95% confidence interval (CI)., Results: In children, the EPP of myopia, hyperopia, and astigmatism was 11.7% (95% CI: 10.5-13.0), 4.6% (95% CI: 3.9-5.2), and 14.9% (95% CI: 12.7-17.1), respectively. The EPP of myopia ranged from 4.9% (95% CI: 1.6-8.1) in South-East Asia to 18.2% (95% CI: 10.9-25.5) in the Western Pacific region, the EPP of hyperopia ranged from 2.2% (95% CI: 1.2-3.3) in South-East Asia to 14.3% (95% CI: 13.4-15.2) in the Americas, and the EPP of astigmatism ranged from 9.8% in South-East Asia to 27.2% in the Americas. In adults, the EPP of myopia, hyperopia, and astigmatism was 26.5% (95% CI: 23.4-29.6), 30.9% (95% CI: 26.2-35.6), and 40.4% (95% CI: 34.3-46.6), respectively. The EPP of myopia ranged from 16.2% (95% CI: 15.6-16.8) in the Americas to 32.9% (95% CI: 25.1-40.7) in South-East Asia, the EPP of hyperopia ranged from 23.1% (95% CI: 6.1%-40.2%) in Europe to 38.6% (95% CI: 22.4-54.8) in Africa and 37.2% (95% CI: 25.3-49) in the Americas, and the EPP of astigmatism ranged from 11.4% (95% CI: 2.1-20.7) in Africa to 45.6% (95% CI: 44.1-47.1) in the Americas and 44.8% (95% CI: 36.6-53.1) in South-East Asia. The results of meta-regression showed that the prevalence of myopia increased from 1993 (10.4%) to 2016 (34.2%) ( P  = 0.097)., Conclusion: This report showed that astigmatism was the most common refractive errors in children and adults followed by hyperopia and myopia. The highest prevalence of myopia and astigmatism was seen in South-East Asian adults. The highest prevalence of hyperopia in children and adults was seen in the Americas.

Purpose: To determine the prevalence of color vision deficiency (CVD) in the northeast of Iran., Methods: This cross-sectional, population-based study was conducted in Mashhad, in the northeast of Iran. Multistage cluster sampling was used for selecting the participants. After preliminary screening, the subjects underwent a complete ophthalmic examination. The examination included the measurement of visual acuity, refraction, and slit-lamp biomicroscopy. The Farnsworth D-15 test was used to detect CVD. The color vision test was done with the best optical correction., Results: Of the 4453 invitees, 3132 participated in the study (response rate: 70.4%). The overall prevalence of CVD in this study was 13.93% [95% confidence interval (CI): 12.44-15.41]. The prevalence of CVD in males and females was 15.85% (95% CI: 13.26-18.44) and 12.96% (95% CI: 11.22-14.71), respectively. The most prevalent types of CVD were tritanopia (6.96%; 95% CI: 5.84-8.08), deuteranopia (3.92%; 95% CI: 3.14-4.70) and tritanomalous (2.21%; 95% CI: 1.55-2.86), respectively. According to the results of logistic regression, the odds of having protanopia were higher in females than males [Odds ratio (OR) = 4.80; 95% CI: 1.20-19.18]. The odds of having deuteranopia were lower in females than males (OR = 0.52; 95% CI: 0.35-0.76). The odds of having CVD were lower in 16-30 (OR = 0.52; 95% CI: 0.37-0.73) and higher in 46-60 (OR: 1.41; 95% CI: 1.01-1.97) year age groups compared to 7-15 year age group. The odds of having tritanopia in 16-30 and 46-60 year age groups was 0.56 (95% CI: 0.35-0.90) and 1.79 (95% CI: 1.19-2.67) compared to 7-15 year age groups, respectively., Conclusion: The prevalence of CVD was high in this study, especially in males and people over 46 years of age. Planning for involvement of ocular disease control programs in health care systems can be helpful in the reduction of CVD and improving the quality of life in affected patients.