Prevalence and Causes of Visual Impairment and Blindness in Elderly Population; an Urgent Geriatric Health Issue: Tehran Geriatric Eye Study (TGES).

PURPOSE: To determine the prevalence of vision impairment (VI) and blindness and their determinants in the elderly population of Tehran. METHODS: In a cross-sectional study, multi-stage cluster sampling was used to select a sample of over 60 year population of Tehran. Optometric examinations included the measurement of uncorrected visual acuity, objective and subjective refraction, presenting and best corrected visual acuity. Vision impairment is reported according to the WHO definition. Visual acuity worse than 20/60 and 20/400 in the better eye was regarded as low vision and blindness, respectively. RESULTS: According to presenting visual acuity, VI was found in 14.8% (95%CI: 13.1-16.5) of the participants, including low vision in 13.8% (95%CI: 12.2-15.4) and blindness in 1.1% (95%CI: 0.5-1.6). The prevalence of VI ranged between 7.8% (95%CI: 6.0-9.5) in subjects aged 60-64 years and 40.0% (95%CI: 33.0-47.0) in participants over 80 years (p < .001). Multivariable logistic regression analysis showed that older age (OR = 1.07(per year)), lower education level (illiterate versus college: OR = 3.55), and lower economic status (middle versus rich: OR = 1.30 and poor versus rich; OR = 1.72) had a significant relationship with an increase in the prevalence of VI, and older age (OR = 1.14(Per year increase)) and diabetes (OR = 2.62) had a significant relationship with blindness. Refractive errors (63.1%) was the leading cause of VI followed by cataract (22.5%). However, cataract (48.3%) was the leading cause of blindness. CONCLUSION: Many older adults suffer from VI. Correction of refractive errors and cataract reduces a large percentage of VI. Age, education level, and economic status are other determinants of VI.

Central corneal thickness and its determinants in a geriatric population: a population-based study.

PURPOSE: To determine the distribution of central corneal thickness (CCT) and its determinants in an Iranian geriatric population. METHODS: This population-based study was conducted in 2019 in Tehran, the capital of Iran, using stratified multistage random cluster sampling. The study population was all residents ≥60 years of age. First, preliminary optometric and ocular health examinations were performed including the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, anterior and posterior segment examination. The study participants then underwent corneal imaging using Pentacam HR. RESULTS: Out of 3791 invitees, 3310 participated in this study (response rate: 87.3%). The mean CCT and apex corneal thicknesses were 528 µ (95% CI: 526-529) and 529 µ (95% CI: 527-530), respectively. The highest and lowest mean corneal thickness was related to the superior (620 µ: 95% CI: 618-622) and the temporal (591 µ: 95% CI: 590-592) paracentral points, respectively. According to the multiple linear regression model, the CCT was significantly inversely related to keratometry readings (K1 and K2) and had a statistically significant direct relationship with intraocular pressure (IOP), corneal eccentricity (ECC), and corneal volume (CV) (all p values <0.05). The CCT was significantly higher in diabetic patients (p = 0.043). CONCLUSION: The CCT values in the geriatric Iranian population were lower than the values reported in most previous studies. The CCT is mostly influenced by IOP and corneal parameters (curvature, shape factor, and volume) and is not affected by demographic factors, refractive error, and ocular biometric components.

Governmental support for achieving "VISION 2020: the Right to Sight" in Iran: the cataract surgical rates.

PURPOSE: The aim of this study was evaluate the effect of governmental support in the form of Health Transformation Plan (HTP) on increasing the cataract surgical rate. METHODS: The number of cataract surgeries was collected from Iranian cataract surgery clinics during 2019. HTP was implemented in 2014. Forty-seven major and forty-five minor surgery centers were selected from all provinces. In each center, sampling was done from 2012, 2013, 2015, and 2016. RESULTS: On average, 6202 and 7134 cataract surgery rate were performed before and after HTP, respectively. The cataract surgical rate rose by 15.03% after the HTP. After HTP, the proportion of cataract surgery increased by 21.32% in governmental centers and decreased by 17.56%, 24.45%, and 14.89% in private, insurance, and charity centers, respectively. The cataract surgical rate was 4093 and 6026 in the first economic quartile (the poorest), 3669 and 4595 in the second quartile, 5884 and 5928 in the third quartile, and 8427 and 9681 in the fourth quartile (the richest) before and after HTP, respectively. The highest growth in the cataract surgical rate was seen in the first quartile (47.24%) followed by the second (25.26%), fourth (14.88%), and third quartiles (0.74%). CONCLUSION: The Health Transformation Plan has been successful in increasing the cataract surgical rate in the low-income group and identifying differences in the services as well as the economic groups within the population.

High prevalence of diabetes in elderly of Iran: an urgent public health issue.

Purpose: To determine the distribution of blood glucose and prevalence of diabetes in people above 60 years living in Tehran and their relationship with some variables. Methods: In this cross-sectional population-based study, multistage cluster sampling was performed in the over 60-year-old population of Tehran. Blood samples were collected from all participants and the data of the history of diabetes and the use of blood glucose lowering agents or other drugs were collected using interviews. Results: Of 3791 selected subjects, 3310 participated in the study (response rate = 87.3%). The mean blood Sugar (BS) and hemoglobin A1c (HbA1c) of the patients was 118.11(95% CI: 115.34 -120.88) and 6.12(95% CI: 6.05-6.2) respectively. The prevalence of diabetes was 29.03%(95% CI: 27.12-30.94) in all subjects, 26.83%(95% CI: 24.58-29.07) in men, and 31.2%(95% CI: 28.24-34.16) in women. Odds of diabetes was significantly worse in women. systolic blood pressure, diasstolic blood pressure, height, weight, waist circumference, wrist circumference, hip circumference, neck circumference and body mass Index were significantly higher in diabetic after adjusting for the effect of sex and age. The odds of blindness was 2.69 (95% CI: 1.10-6.59) times higher in diabetic than in non-diabetics. Conclusions: On average, one in every three persons above 60 years of age was diabetic. Therefore, attention should be paid to this age group, especially women, due the higher prevalence of diabetes. All anthropometric measurements except height had a strong correlation with diabetes. Blindness was significantly more in diabetics.

Global and Regional Prevalence of Diabetic Retinopathy; A Comprehensive Systematic Review and Meta-analysis.

PURPOSE: We conducted a systematic search to estimate DR prevalence in different age and gender groups, and to evaluate the determinants of heterogeneity in its prevalence. METHODS: A systematic and comprehensive search from inception to August 10, 2020, was done in international databases, including Scopus, PubMed, Web of Science, Embase, and other data sources without any restriction to find cross-sectional studies related to the prevalence of DR. RESULTS: Of 6399 studies, 90 articles with a sample size of 563460 individuals and 204189 diabetic patients were analyzed. The estimated pooled prevalence of DR in the diabetic population in general; in female and in male was 28.41% (95% CI: 25.98 to 30.84); 25.93% (95% CI: 23.54 to 28.31) and 28.95% (95% CI: 26.57 to 31.32); respectively and the prevalence of DR showed no inter-gender difference. The heterogeneity of the pooled prevalence according to I2 was 99% (p < .001). According to the meta-regression results, the variables of WHO region (Coefficient of AMRO vs SEARO: 15.56; p: 0.002), age (Coefficient of above 60 years vs below 40 year: 18.67; p: 0.001), type of DR (Coefficient: 19.01; p < .001), and publication year (Coefficient: -0.60; p: 0.001) had a significant correlation with heterogeneity. CONCLUSION: One third of diabetic patients suffered from DR, mostly NPDR. DR increased markedly after the age of 60 years, which could be due to the longer duration of diabetes. Age, WHO region, type of DR, and publication year affected the heterogeneity in the prevalence of DR.

Abnormal Visual Function: An Under-recognized Risk Factor of Road Traffic Injuries.

Purpose: To determine the relationship between road accidents with visual acuity, refractive errors, visual field, and contrast sensitivity. Methods: This population-based case-control study was conducted on roads leading to Tehran Province, Iran. The case group comprised drivers who had met with accidents and were at fault for the accident. The cases were selected in an ongoing manner (incidence cases). The controls were drivers who were the opposing victims in the same. After an initial interview, optometric and ophthalmic examinations including the measurement of visual acuity, refraction, visual field assessment, contrast sensitivity measurement, and slit lamp biomicroscopy were performed for all study participants. Results: In this study, 281 and 204 individuals were selected for the case and control groups. The mean uncorrected visual acuity was 0.05 ± 0.12 and 0.037 ± 0.10 logMAR in the case and control groups, respectively (P = 0.095). Of the participants in the case and control groups, 32.8% and 23% had a visual field defect in at least one eye, respectively (adjusted odds ratios [aOR] = 1.63, 95% confidence interval [CI]: 1.08-2.48; P = 0.021). Moreover, 16.2% of the cases and 8.3% of the controls had visual field defects in both eyes (aOR = 2.13, 95% CI: 1.17-3.86; P = 0.012). Contrast sensitivity was worse in the case group in all spatial frequencies under non-glare conditions. However, under glare conditions, the contrast sensitivity was significantly worse in the case group only in the spatial frequency of 12 cycles per degree (cpd). Conclusion: Reduced contrast sensitivity, especially under non-glare conditions, and visual field defects are risk factors that influence the prevalence of road accidents. It is strongly advised that special attention be paid to these visual functions in legal assessments to apply the necessary interventions in individuals with these types of disorders.

Prevalence and risk factors of pterygium: a systematic review and meta-analysis.

The present study was conducted to determine the global prevalence and risk factors for pterygium. Three thousand two hundred fifty-five articles were identified, of which 68 articles with a total of 415,911 participants from 24 countries were included in the final analysis. The prevalence of pterygium in the total population was 12% (95% confidence interval [CI] 11-14%). The lowest and highest prevalence rates were, respectively, 3% (95% CI 0.0-9%) in the 10- to 20-year-age group and 19.5% (95% CI 14.3-24.8%) in those over 80 years. The prevalence was 13% (95% CI 11-15%) in men and 12% (95% CI 9-13%) in women. The odds ratio for men was 1.30 (95% CI 1.14-1.45). The lowest prevalence of pterygium was reported in a clinic-based study in Saudi Arabia (0.07%) and the highest prevalence was in China (53%). The odds were 1.24 (95% CI 1.11-1.36) for sunlight exposure over 5 hours, 0.84 (95% CI 0.74-0.94) for smoking, 1.45 (95% CI 1.33-1.57) for living in rural areas, 1.17 (95% CI 1.03-1.32) for alcohol consumption, 1.46 (95% CI 1.36-1.55) for outdoor occupations, and 0.47 (95% CI 0.19-0.57) for use of sunglasses. This is the second meta-analysis arriving at an estimate of 12% for the prevalence of pterygium. According to our results, pterygium risk factors fall in 3 categories: demographic, environmental, and lifestyle factors. Older age, male gender, outdoors occupation, and living in rural environments are the leading demographic risk factors for the development of pterygium. Exposure to sunlight is the most common environmental risk factor, and the results of this study provide a more exact and reliable value of the effect of sunlight exposure. The use of sunglasses and cigarette smoking are protective factors, and the significant effect of alcohol consumption is related to lifestyle factors.

Cataract surgical rate in Fars Province: Distribution and trend from 2006 to 2010.

PURPOSE: To determine changes in cataract surgical rate (CSR) in Fars Province from 2006 to 2010 and identify the contributions of public and private sectors. METHODS: This descriptive report is part of the Iranian Cataract Surgery Survey. To determine the provincial CSR, weights of major (>3000 annual surgeries) and minor (≤3000) centers were calculated based on the number of centers chosen for each year and multiplied by their numbers of surgeries. To determine public and private sectors' contributions, the numbers of surgeries in each sector were estimated based on the number of sampled centers. RESULTS: Overall, CSR improved by 25%; the number of CS decreased by 16% in the public sector and increased by 157% in the private sector. In 2006, the public sector contributed to 69% of the CSR, and by 2010, this rate had decreased to 43%. CONCLUSION: The decreasing contribution of the public sector calls for studies to identify causes and remove potential barriers.

OPD-Scan III: a repeatability and inter-device agreement study of a multifunctional device in emmetropia, ametropia, and keratoconus.

The purpose of this study was to test the measurements of a multifunctional device, the NIDEK OPD-Scan III in terms of repeatability and agreement with retinoscopy and Pentacam in cases with emmetropia, ametropia, and KCN (grade 1-3). We enrolled 170 eyes (40 in each group of emmetropia and ametropia, and 90 in the 3 KCN subgroups). Acquisitions were done twice by a single technician to check the intra class correlation, repeatability index, and precision. To assess agreement, we compared OPD-Scan III with retinoscopy and Pentacam results by two blinded technicians. All device functions had acceptable precision in groups with emmetropia, ametropia, and KCN1, except spherical error in ammetropics (0.97 D). In KCN2, repeatability was acceptable with the refractive function, topography, and ocular aberrations but was more than 1.0 D for corneal aberrations. In KCN3, repeatability was low for the refractive function and corneal spherical aberration. Refractive data were not convertible to those obtained by retinoscopy in any group. OPD-Scan III keratometry data were interchangeable with Pentacam counterparts in emmetropes, ammetropes, and KCN1. In KCN2, the OPD-Scan III-Pentacam agreement for Kmax was 0.71 D, and there was 1.25 D difference in Kmin. No OPD-Scan III-Pentacam agreement was observed in KCN3. OPD- Scan III is a multifunctional device with acceptable repeatability in emmetropic, ammetropic, and KCN cases. Its measurements of corneal curvature and ocular aberrations are better than other functions. In cases with high degrees of refractive error and corneal irregularities, device repeatability and agreement with Pentacam is decreased.

Complications of Cataract Surgery in Iran: Trend from 2006 to 2010.

PURPOSE: To determine intraoperative complications of cataract surgery over the period 2006 to 2010. METHODS: In this cross-sectional study, 106 of 272 cataract surgical centers in Iran were selected through multistage random cluster sampling from all provinces. In each province, the selected number of centers was proportionate to the number of cataract surgeries, and in each center, the selected number of charts was proportionate to the center's number of cataract surgeries, from which we retrieved intraoperative complications. RESULTS: The prevalence of intraoperative complications of cataract surgery was 5.04% (95% confidence interval, CI, 3.53-6.54%) in 2006, which decreased significantly to 3.44% (95% CI 1.84-5.04%) in 2010. The most common complication was posterior capsular rupture/vitreous loss which decreased from 4.29% (95% CI 2.93-5.66%) in 2006 to 2.81% (95% CI 1.3-4.31%) in 2010. The next most common complication was suprachoroidal hemorrhage at 0.56% (95% CI 0.25-0.87%) in 2006 and 0.46% (95% CI 0.3-0.62%) in 2010. The least common complication concerned intraocular lens (IOL)-drop. Complications were seen most with lensectomy, while phacoemulsification caused the least complications. Mean hospitalization time in uncomplicated cases was 0.59 days (95% CI 0.58-0.61 days) and in complicated cases 1.14 days (95% CI 1.07-1.20 days; p < 0.001). CONCLUSION: Complications of cataract surgery in Iran had a decreasing trend during 2006-2010. However, results from 2010 indicate that cataract surgical complications still need to be focused on. Hospitalization was longer for cases with complications, and further reducing this could help decrease costs of cataract surgery.

Intraoperative Complications of Cataract Surgery in Tehran Province, Iran.

PURPOSE: To determine the prevalence and types of intraoperative complications of cataract surgery and examine potential risk factors. METHODS: Data were obtained from the 2011 Iranian Cataract Surgery Survey in which information about cataract surgeries throughout the nation was collected. In the Province of Tehran, 55 centers and 1 week per season per center were randomly selected for sampling. In each center, the charts of all patients who underwent cataract surgery during the selected weeks (total of 20 weeks per center) were reviewed for data extraction. The prevalence of different types of intraoperative cataract surgery complications were determined, and their relationships with age, sex, surgical method, surgeon, and hospitalization time were examined. RESULTS: The prevalence of intraoperative complications of cataract surgery was 4.15% (95% confidence interval, 0.94 to 7.36). The prevalence of posterior capsular rupture with vitreous loss, posterior capsular rupture without vitreous loss, retrobulbar hemorrhage, suprachoroidal effusion/hemorrhage, intraocular lens drop, and nucleus drop was 2.86, 0.69, 0.06, 0.39, 0.03, and 0.11%, respectively. The prevalence of cataract surgery complications decreased from 6.95% in 2006 to 3.07% in 2010. The results of multiple logistic regression showed that surgery by residents, nonphacoemulsification methods of surgery, and patient age less than 10 years and more than 70 years were the risk factors for complications. CONCLUSIONS: This study evaluated the prevalence of intraoperative complications of cataract surgery for the first time in Tehran Province. The prevalence of complications was high in this study. To achieve the goals of the Vision 2020 Initiative and improve surgical quality, it is necessary to minimize complication rates. Factors to note for decreasing complication rates include type of surgery, surgeon experience, and patient age.

Cataract Surgical Rate between 2006 and 2010 in Tehran Province.

BACKGROUND: Considering population aging in Iran and the importance of cataract surgery in the old age, this study was performed to show the cataract surgical rate (CSR) between 2006 and 2010 in Tehran Province. METHODS: Eighteen centers were randomly selected from cataract surgery centers in Tehran. In each center, one week in every season was randomly selected and the number of cataract surgeries in the week was calculated. In total, 20 weeks were selected in each center in five years. RESULTS: The CSR increased linearly from 8011 cases per 1,000,000 population in 2006 to 12465 cases per 1,000,000 population in 2010. As for patients below 40 years of age, the percentage of the male patients was more while after the age of 40 years, the percentage of the female patients was more in all age groups. At least 96.2% of the surgeries in each year were performed using the phacoemulsification method. From 2006 to 2010, the percentage of outpatient surgery increased from 48.7% to 72.5%. On the other hand, hospitalization for one night or more had a decreasing trend from 2006 to 2010. CONCLUSION: During 2006-2010, the CSR was acceptable in Tehran in comparison with other studies. However, attention should be paid to the increase in the population of the elderly people. Although more than 95% of the surgeries in the Province of Tehran are performed using the phacoemulsification method, the rate should increase to 100% in the eligible cases.

The Prevalence and Causes of Visaual Impairment and Blindness in a Rural Population in the North of Iran.

BACKGROUND: Visual impairment is a very important public health problem. In Iran, reports of visual impairment and blindness have been published from the urban population while the prevalence of visual impairment in the rural population has not been reported. The purpose of this study to determine the prevalence and causes of visual impairment, in a rural population in district of based on age and sex. METHODS: In a cross-sectional population-based study, using random cluster sampling, 13 of the 83 villages of Khaf County in the north east of Iran were selected. Eye examinations were performed in a Mobile Eye Clinic (Nooravaran Salamat, 2011) and included optometric examinations such as measuring uncorrected and corrected visual acuity along with non-cycloplegic refraction. RESULTS: The prevalence of visual impairment, low vision, and blindness was 6.3% (95% CI 5.3-7.3), 3.4% (95% CI 2.6-4.1), and 3.0% (95% CI 2.3-3.6), respectively. The prevalence of visual impairment ranged from 1.8% in the participant younger than 20 years of age to 28% in the subjects aged 60 and over (P<0.001). After matching for age, the prevalence of visual impairment and low vision was significantly higher in women. The most prevalent causes of visual impairment were uncorrected refractory error (54.5%) and cataract (17.6%). CONCLUSION: The prevalence of visual impairment was significantly higher in the rural population of this study when compared to previous reports from Iran. It seems that provision of therapeutic facilities like cataract surgery and availability of eyeglasses in villages can considerably reduce the prevalence of visual impairment.

Distribution of cataract surgical rate and its economic inequality in Iran.

PURPOSE: To determine the distribution of the cataract surgical number per million population per year (CSR), the CSR in the population older than 50 years (CSR 50+) in the provinces of Iran, and their economic inequality in 2010. METHODS: As part of the cross-sectional 2011 CSR survey, the provincial CSR and CSR 50+ were calculated as the total number of surgeries in major and minor centers divided by the total population and the population older than 50 years in each province. Economic inequality was determined using the average province income, the average urban and rural household incomes, and the percentage of urban and rural population in each province. RESULTS: Tehran and Ilam provinces had the highest and lowest CSR (12,465 vs. 359), respectively. Fars and Ilam provinces had the highest and lowest CSR 50+ (71,381 vs. 2481), respectively. Low CSR (<3000) was detected in 9 provinces where 2.4 to 735.7% increase is needed to reach the minimum required. High CSR (>5000) was observed in 14 provinces (45.2%) where rates were 0.6 to 59.9% higher than the global target. Cataract surgical rate increased at higher economic quintiles. Differences between the first, second, and fifth (poorest) quintiles were statistically significant. The CSR concentration index was 0.1964 (95% confidence interval, 0.0964 to 0.2964). CONCLUSIONS: In line with the goals of the Vision 2020 initiative to eliminate cataract blindness, more than 70% of geographic areas in Iran have achieved the minimum CSR of 3000 or more. However, a large gap still exists in less than 30% of areas, mainly attributed to the economic status.

Ionizing radiation-induced cataract in interventional cardiology staff.

BACKGROUND: The use of ionizing radiation has led to advances in medical diagnosis and treatment. OBJECTIVES: The purpose of this study was to determine the risk of radiation cataractogenesis in the interventionists and staff performing various procedures in different interventional laboratories. PATIENTS AND METHODS: This cohort study included 81 interventional cardiology staff. According to the working site, they were classified into 5 groups. The control group comprised 14 professional nurses who did not work in the interventional sites. Participants were assigned for lens assessment by two independent trained ophthalmologists blinded to the study. RESULTS: The electrophysiology laboratory staff received higher doses of ionizing radiation (17.2 ± 11.9 mSv; P < 0.001). There was a significant positive correlation between the years of working experience and effective dose in the lens (P < 0.001). In general, our findings showed that the incidence of lens opacity was 79% (95% CI, 69.9-88.1) in participants with exposure (the case group) and our findings showed that the incidence of lenses opacity was 7.1% (95% CI:2.3-22.6) with the relative risk (RR) of 11.06 (P < 0.001). CONCLUSIONS: We believe that the risk of radiation-induced cataract in cardiology interventionists and staff depends on their work site. As the radiation dose increases, the prevalence of posterior eye changes increases.

Effect of anterior chamber depth on the choice of intraocular lens calculation formula in patients with normal axial length.

PURPOSE: To compare the accuracy of  Sanders-Retzlaff-Kraff II (SRK II) and 3(rd) and 4(th) generation intraocular lens (IOL) formulas and to compare the effect of different anterior chamber depths among the IOL formulas in cataract patients with normal axial length (AL; 22.0-24.5 millimeters, mm). MATERIALS AND METHODS: A retrospective chart review was performed of patients with normal AL who underwent cataract surgery. The SRK II and 3(rd) generation IOL formulas (Hoffer Q, SRK T, Holladay 1) were compared to the 4(th) generation Haigis formula. For analysis, preoperative anterior chamber depth (ACD) was divided into three subgroups: ≤3, 3-3.5, and ≥ 3.5 mm. The mean error (ME) and mean absolute error (MAE) of each formula was compared for each subgroup against the total. The difference between the ME and MAE of the formulas were compared for each ACD subgroup. P < 0.05 was considered statistically significant. RESULTS: The study sample was comprised of 309 eyes. The MAE were 0.56 D, 0.52 D, 0.51 D, 0.50 D, and 0.50 D with Haigis, Hoffer Q, SRK T, Holladay 1, and SRK II formulas, respectively. The Haigis formula was a significantly weaker predictor than the SRK T (P < 0.001) and Holladay 1 (P = 0.035) formulas. The ME with Haigis formula was -0.23 D which changed to -0.06 D with ACD ≥ 3.5 mm (P = 0.002). The ME was -0.24 D with SRK II and changed to -0.09D with ACD ≤ 3 mm (P = 0.004). There was no statistically significant difference between Hoffer Q, SRK T, and Holladay formulas 1 in ACD subgroups (P > 0.05, all comparisons). CONCLUSION: The SRK II formula can predict refraction in patients with normal AL and ACD less than 3 mm with less error and is preferred over other formulas. The Haigis formula is the preferred choice in patients with a normal AL and ACD longer than 3.5 mm. The prediction accuracy of Hoffer Q, SRK T, and Holladay 1 is comparable in normal AL.

Prevalence of Refractive Errors among High School Students in Western Iran.

PURPOSE: To determine the prevalence of refractive errors among high school students. METHODS: In a cross-sectional study, we applied stratified cluster sampling on high school students of Aligoudarz, Western Iran. Examinations included visual acuity, non-cycloplegic refraction by autorefraction and fine tuning with retinoscopy. Myopia and hyperopia were defined as spherical equivalent of -0.5/+0.5 diopter (D) or worse, respectively; astigmatism was defined as cylindrical error >0.5 D and anisometropia as an interocular difference in spherical equivalent exceeding 1 D. RESULTS: Of 451 selected students, 438 participated in the study (response rate, 97.0%). Data from 434 subjects with mean age of 16±1.3 (range, 14 to 21) years including 212 (48.8%) male subjects was analyzed. The prevalence of myopia, hyperopia and astigmatism was 29.3% [95% confidence interval (CI), 25-33.6%], 21.7% (95%CI, 17.8-25.5%), and 20.7% (95%CI, 16.9-24.6%), respectively. The prevalence of myopia increased significantly with age [odds ratio (OR)=1.30, P=0.003] and was higher among boys (OR=3.10, P<0.001). The prevalence of hyperopia was significantly higher in girls (OR=0.49, P=0.003). The prevalence of astigmatism was 25.9% in boys and 15.8% in girls (OR=2.13, P=0.002). The overall prevalence of high myopia and high hyperopia were 0.5% and 1.2%, respectively. The prevalence of with-the-rule, against-the-rule, and oblique astigmatism was 14.5%, 4.8% and 1.4%, respectively. Overall, 4.6% (95%CI, 2.6-6.6%) of subjects were anisometropic. CONCLUSION: More than half of high school students in Aligoudarz had at least one type of refractive error. Compared to similar studies, the prevalence of refractive errors was high in this age group.

Cataract surgical rate in Iran: 2006 to 2010.

PURPOSE: To determine the cataract surgical rate (CSR) between 2006 and 2010 in Iran. METHODS: In this cross-sectional study, sampling was done from surgical centers throughout Iran. Centers throughout all of Iran with more than 3000 surgeries per year were grouped as major centers and the rest were grouped as minor centers. All major centers and a percentage of minor centers were selected from each province. For each center, we determined the number of cataract surgeries in a random week of each season. RESULTS: Of the 237 eligible surgical centers, 124 were selected and 106 were enrolled in the study; 80 were major centers and 26 were minor centers. The number of surgeries has increased from 335,948 in 2006 to 475,526 in 2010. Cataract surgical rate has increased from 4723 (95% confidence interval, 4707 to 4739) per million population in 2006 to 6328 (95% confidence interval, 6309 to 6346) per million population in 2010. In the 50 and older population, CSR was 38,450 per million population in 2010. Average annual number of cataract surgeries per surgeon was 263 in 2006 and 339 in 2010. CONCLUSIONS: Compared with previous studies, the 2006 to 2010 CSR in Iran is on an ascending trend. Also, our numbers are higher than the minimum recommended by the World Health Organization, although lower than that in Western countries. Considering the aging population of the country, the observed rate is not sufficient for all cases of cataract in the future, and there is a need to increase CSR throughout the nation.

The prevalence of astigmatism and its determinants in a rural population of Iran: the "Nooravaran Salamat" mobile eye clinic experience.

PURPOSE: The prevalence of astigmatism, and the astigmatic axis, and their determinants were evaluated in a rural population of Iran. MATERIALS AND METHODS: In a cross-sectional study conducted from May to August 2011, 13 villages in the vicinity of the city of Khaf in northeast Iran were investigated in this study. All the examinations including visual acuity, refraction, slit-lamp biomicroscopy and fundoscopy were performed in a Mobile Eye Clinic. Written informed consent was obtained from all participants. Only phakic eye that could be reliably refracted without a previous history of ocular surgery were included. RESULTS: Out of 2635 participants who were screened, 2124 were analysed for this study of whom 52% were female. The prevalence of astigmatism was 32.2% (95% confidence intervals (CI): 30.2-34.2). Astigmatism significantly increased from 14.3% in the under 15-year-old age group to 67.2% in the age group of over 65-years old (P < 0.001). The prevalence of With-The-Rule (WTR), Against-The-Rule (ATR), and oblique astigmatism was 11.7%, 18.1%, and 2.4 %, respectively. ATR significantly increased with age (P < 0.001). The mean corneal astigmatism was 0.73 D which linearly increased with age (P < 0.001). CONCLUSION: Attention must be paid to astigmatism in rural areas due to the high prevalence. Further studies are suggested to discover the role of the environmental and genetic factors. It seems that environmental and occupational factors in the villages cause a significant increase in the prevalence of astigmatism with age. A high percentage of participants had ATR astigmatism, which was more common at older ages.

ClearKone-Synergeyes or rigid gas-permeable contact lens in keratoconic patients: a clinical decision.

OBJECTIVE: To compare the best-corrected visual acuity (BCVA), vision-related quality of life (VRQoL), comfort, foreign body sensation in the eye, tolerance, and handling of ClearKone-Synergeyes hybrid contact lenses and rigid gas-permeable (RGP) lenses in patients with keratoconus. METHODS: This comparative case series was conducted between 2011 and 2012 on 40 keratoconic patients (20 in each group). The BCVA of each patient was evaluated on the same day when the lens was prescribed. The National Eye Institute Visual Functioning Questionnaire (NEI-VFQ 25) questionnaire was assessed in addition to other subjective criteria 2 months after the lens prescription. RESULTS: The BCVA did not show a significant difference between the two lenses. Of the subjective criteria, the scores of the domains of general vision (P=0.008), ocular pain (P<0.001), distance activity (P=0.008), mental health (P<0.001), role difficulty (P<0.001), dependency (P=0.016), driving (P=0.067), total score of the NEI-VFQ 25 questionnaire (P<0.001), and comfort (P<0.001) were significantly higher in the ClearKone-Synergeyes group when compared with the RGP group. Foreign body sensation was statistically higher with RGP lens versus the ClearKone-Synergeyes lens (P=0.013). Regarding tolerance, the preference of the ClearKone-Synergeyes lens over the RGP lens was borderline (P=0.085). CONCLUSION: Although the BCVA did not differ significantly between the two lenses and both corrected vision to the same extent, satisfaction and VRQoL was better in keratoconic patients who used the ClearKone-Synergeyes lens in comparison with the RGP lens.