A longitudinal study of local stereoacuity and associated factors in schoolchildren: The Shahroud Schoolchildren Eye Cohort Study.

CLINICAL RELEVANCE: Impaired stereoacuity is seen in some children without amblyopia, strabismus, and clinically significant refractive errors. Therefore, there are probably other factors affecting stereoacuity. BACKGROUND: The aim of this work was to investigate the longitudinal changes of local stereoacuity and associated factors in schoolchildren. METHODS: The present report is a part of the Shahroud Schoolchildren Eye Cohort Study. The target population was children aged 6 to 12 years in Shahroud, Iran. The second phase of the study was conducted in 2018 by re-inviting all participants in the first phase (2015). After an initial interview, study participants underwent optometric examination and ocular biometry. Stereoacuity was evaluated using Stereo Fly Test. Exclusion criteria were functional amblyopia, strabismus, significant refractive errors, probable ocular pathology/organic amblyopia in either of the two study phases, a history of intraocular surgery or ocular trauma, and incomplete data. RESULTS: The data of 4666 children were analysed for this report, of which 53.7% were male. The mean age of the studied participants in the second phase was 12.37 ± 1.71 years. The mean stereoacuity was 42.31 (95% CI: 42.05 - 42.57) seconds of arc in the first phase, which reduced to 51.72 (95% CI: 50.79-52.65) seconds of arc in the second phase (P < 0.001). The prevalence of poor stereoacuity was 0.17% (95% CI: 0.06-0.29) in the first phase, which increased to 3.94% (95% CI: 3.34-4.54) in the second phase (P < 0.001). According to the multiple linear regression, older age in the first study phase (ß = 0.011, P < 0.001), urban residence (ß = -0.019, P = 0.006), increased spherical anisometropia (0.038, P = 0.013), and increased axial length (ß = 0.062, P = 0.003) were significantly associated with reduction of stereoacuity (in log scale) after three years. CONCLUSION: In addition to the known risk factors of amblyopia, strabismus, and significant refractive errors, other factors are also associated with stereoacuity changes in children.

Astigmatism profile in the elderly population: Tehran Geriatric Eye Study.

PURPOSE: To determine the prevalence of astigmatism and its associated factors and examine astigmatism symmetry patterns in an elderly population. STUDY DESIGN: Population based cross-sectional study. METHODS: The present population-based cross-sectional study was conducted on an elderly population above 60 years of age in Tehran, Iran in 2019. The sampling was done using the stratified multistage random cluster sampling method. All study participants underwent a complete optometric examination and slit-lamp biomicroscopy. RESULTS: The prevalence of astigmatism higher than -0.50, -1.00, and -2.00 D was 83% (95% CI: 81 -84), 52 % (95% CI: 50 -54), and 19% (95% CI: 17-20), respectively. These prevalence was 79%(95% CI: 77-81), 46(95% CI: 44-49) and 14(95% CI: 13-16) in subjects without a history of ocular surgery, respectively. Based on cylinder power worse than -1.00 D, 10% (95% CI: 9-12), 20% (95% CI: 18-22), and 21% (95% CI:19-23) of study participants had with the rule, against the rule, and oblique astigmatism, respectively. According to the results of the multiple regression model, male gender, older age, low education level, pure posterior subcapsular cataract, pseudophakia, and myopia were independent factors associated with astigmatism. The prevalence of anisorule astigmatism was 57 % (95% CI: 56-59), the most common anisorule astigmatism was against the rule-oblique type with a prevalence of 36% (95% CI: 34-38). CONCLUSION: The prevalence of astigmatism was high in the elderly population of Tehran. More than half of the participants in this study had anisorule astigmatism, and against the rule-oblique combination was more prevalent than other types. A posterior subcapsular cataract, a history of cataract surgery, and myopia were the associated factors of astigmatism in this study.

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

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

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

BACKGROUND: To determine the distribution of the near point of convergence (NPC) and its related factors in an elderly population in Tehran, Iran. METHODS: This population-based cross-sectional study was conducted on the elderly population (60 years of age and over) of Tehran, Iran in 2019. The samples were selected using stratified random cluster sampling. The examinations included the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, unilateral and alternate cover test, ocular health examination, and NPC measurement. RESULTS: The mean age of the participants was 65.90 ± 4.56 years and 59.6% of them were females. The mean (95% CI) NPC in the total sample was 7.84 cm (95% CI: 7.65-8.03). The mean (95% CI) NPC in males and females was 7.92 cm (7.63-8.21) and 7.75 cm (7.54-7.97) (P = 0.338), respectively. The mean NPC increased from 7.8 cm (95% CI: 7.55-8.05) in the age group 60-64 years to 8.83 cm (95% CI: 7.47-10.2) in the age group ≥ 80 years (P > 0.05). The mean (95% CI) NPC in emmetropic, myopic, and hyperopic individuals was 7.67 cm (95% CI: 7.33-8.02), 7.96 cm (7.56-8.37), and 7.87 cm (7.63-8.11), respectively (P = 0.378). There was no statistically significant relationship between NPC with education level, smoking, diabetes mellitus (DM), and hypertension (HT). CONCLUSIONS: The NPC values found in this study were significantly lower (less remote) than the values reported in previous studies in similar age groups. The NPC had no significant relationship with age, sex, education level, smoking, DM, and HT.

Ocular biometry characteristics in cataract surgery candidates: a cross-sectional study.

Background: This study was conducted to investigate ocular biometry parameters in cataract surgery candidates in northern Tehran, Iran using OA-2000 biometry device. Methods: In this cross-sectional study, values of ocular biometry parameters, including axial length (AL), anterior chamber depth (ACD), mean corneal curvature (mean K), lens thickness (LT), corneal astigmatism (CA), and white-to-white (WTW) of 818 eyes with cataracts, were measured using the OA-2000 biometry device (Tomey, Nagoya, Japan). The participants were divided into si age subgroups, in 10-year intervals. Finally, the values of the biometry parameters were calculated, and the trend of changes was examined for both age and sex subgroups. Results: The mean (standard deviation [SD]) of age of the participants was 63.82 (13.25) years. Mean (SD) of biometry parameters were as follows: AL, 23.36 (1.55) mm; ACD, 3.09 (0.40) mm; LT, 4.45 (0.55) mm; mean K, 44.51 (1.72) D; CA, 1.06 (0.94) D; and WTW, 11.81 (0.45) mm. Most of the parameters showed significant age-related changes in the total population. There was an increase in LT (P < 0.001) and mean K (P = 0.001), as well as a decrease in AL (P < 0.001) and ACD (P < 0.001) with age. Moreover, AL had a negative negligible correlation with LT (r = - 0.24; P < 0.001) and mean K (r = - 026; P < 0.001), as well as a weak positive correlation with ACD (r = + 0.44; P < 0.001). Conclusions: Our study revealed that the mean values of most biometric parameters varied across age and sex subgroups. Moreover, most of the parameters showed significant age-related changes in the total population.

The Characteristics of Excimer Laser Refractive Surgery Candidates.

PURPOSE: To determine the demographic and refractive characteristics of excimer laser refractive surgery candidates in Iran. METHODS: This was a cross-sectional study between 2010 and 2014. All information was collected from 28 centers randomly selected from 12 provinces. Then, for each season of the year, one week was chosen through simple random selection, and within each week, 3 days were again chosen randomly. All excimer laser surgical procedures performed during these 3 days were identified by training staff, and data were extracted from patient charts. RESULTS: A total of 14,569 charts were reviewed; 67.5% of the subjects were female and the rest were male. Of the total surgeries, 18.6% had been done in 2010 which reached to 19.1% in 2014. The mean age of people receiving refractive surgery showed an upward trend (P<0.001) and female patients were significantly younger than male patients (P<0.001). The 25 to 39 years age group received the highest number of surgeries (31.9% of the total) and there was a significant association with gender (P<0.001). The most common refractive error was compound myopic astigmatism with a prevalence of 79.3%. In 2010, 33.3% of the performed surgeries were covered by insurance policies, and this decreased to 30.2% in 2014 (P<0.001). CONCLUSION: Women with compound myopic astigmatism in the age range of 25 and 35 years are the most frequent users of excimer laser refractive surgery. Less than one-third of laser refractive surgeries are covered by insurance policies. Therefore, proper planning for improving services to this group must be given priority.