Five-year changes in macular thickness in the elderly population: A cohort study.

BACKGROUND: The aim of this study is to determine the 5-year changes in macular thickness and related factors. METHODS: Data were from the second (2014) and third (2019) phases of the Shahroud Eye Cohort Study. Examinations included measurement of uncorrected and best-corrected visual acuity, non-cycloplegic autorefraction, slit-lamp biomicroscopy, and funduscopy. Participants underwent Cirrus HD-OCT 4000 (Carl Zeiss Meditec, Dublin, CA). RESULTS: The 5-year changes (95% confidence interval) of central and overall macular thicknesses were - 3.48 ± 8.16 µ (-3.92, -3.03) and - 0.79 ± 4.06 µ (-1.03, -0.54), respectively. The median and IQR of 5-year changes in the central subfield thickness were -3 and 10, although they were 0 and 5 in the overall macular thickness, respectively. Multiple regression model showed the central macular thickness (CMT) decreased with a U-shape pattern with increasing age. The 5-year changes in CMT were significantly lower in females compared to males ß = -1.55; (-2.78, -0.32) and in smokers compared to non-smokers ß = -1.92; (-3.55, -0.28). Moreover, higher body mass index ß = -0.12; (-0.22, -0.02) and CMT at baseline ß = -0.08; (-0.10, -0.06) were significantly associated with lower CMT changes. The average 5-year changes in overall macular thickness showed a non-linear decrease with age and was significantly higher in females ß = 0.93; (0.4, 1.43). These changes were directly related to the anterior chamber depth ß = 0.87; (0.10, 1.64) in the baseline. CONCLUSIONS: The macular thickness decreased slightly after 5 years; however, this change is not clinically significant. Demographic factors such as age and sex and refractive errors were significantly related to macular thickness changes.

MACULAR THICKNESS BY USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY IN CHILDREN AND ADOLESCENTS.

PURPOSE: To determine the distribution of macular and cube thickness and their normal range in the students aged 9 years to 15 years and to investigate their associated demographic and biometric factors. METHODS: This study was based on the data of the second phase of the Shahroud School Children Eye Cohort Study, conducted in 2018. After measurements of visual acuity, biometry, and subjective and cycloplegic refraction, retinal examination was performed using the Zeiss Cirrus HD 4000 optical coherence tomography. RESULTS: The data of 5,043 right eyes were analyzed after applying the exclusion criteria. The central macular thickness was 239 ± 19.35 µ m. The mean cube volume and cube thickness were 9.94 ± 0.44 and 278 ± 12.20, respectively. According to multiple linear regression analysis, the central macular thickness was significantly lower in girls (coefficient [ß]: -9.18; P < 0.001) and rural students (ß: 3.86; P < 0.001) and had a direct association with axial length (ß: 5.19; P < 0.001), lens thickness (ß: 5.33; P = 0.003), and mean keratometry (ß: 2.41; P < 0.001). The cube volume was lower in girls (ß: -0.13; P < 0.001) and higher in rural students (ß: 0.05; P < 0.001). CONCLUSION: Macular thickness was slightly higher in Iranian children. Sex, living place, axial length, lens thickness, and mean keratometry were the main associated factors with macular thickness.

Long-term effects of methamphetamine abuse on visual evoked potentials.

PURPOSE: To compare visual evoked potential (VEP) components in normal individuals and those with long-term methamphetamine and crystal methamphetamine use. METHODS: In this study, monocular pattern-reversal VEPs were recorded in 40 methamphetamine and crystal methamphetamine users and 38 normal individuals. Visual stimuli were high-contrast (99%) checkerboard patterns at 15 and 60 min of arc with a reversal rate of 1.53 reversals per second. RESULTS: A significant difference was seen between the two groups for the P100 peak time for the 60 min of arc checks (p = 0.002, d = 0.75, 4.61% higher peak time in the addicted group) and the 15 min of arc checks (p = 0.004, d = 0.73, 4.78% higher peak time in the addicted group). However, other VEP components were not significantly different between the two groups. CONCLUSIONS: The higher P100 peak time at both 15 and 60 min of arc in methamphetamine-dependent users reveals that VEPs are highly sensitive for the diagnosis of retinal and visual pathway lesions.

Macula and optic disk features in methamphetamine and crystal methamphetamine addicts using optical coherence tomography.

PURPOSE: Methamphetamine and crystal methamphetamine abusers were compared with healthy subjects using optical coherence tomography to assess their retinal nerve fiber layer, macula, and optic disk characteristics. METHODS: Forty-one methamphetamine and crystal methamphetamine abusers and 42 healthy subjects (mean ± SD of age: 35.82 ± 8.6 and 37.76 ± 9.1 years, respectively) were incorporated in this cross-sectional study. The drug abusers had a history of at least five years of substance use through smoking. Fourier-domain optical coherence tomography was used to image and assess the characteristics of retinal nerve fiber layer, macular thickness, and optic disk in the study groups. RESULTS: The retinal nerve fiber layer thickness was significantly lower in the superior and temporal retinal quadrants of drug abusers than healthy subjects (P = 0.008 and P = 0.028, respectively). This study did not find a significant difference between drug abusers and healthy controls regarding optic to disk ratio, rim area, and disk area (P > 0.05). The comparison between the study groups showed that the reductions in perifovea and the superior quadrant of parafoveal thickness were statistically significant (P < 0.001 and P = 0.029, respectively). CONCLUSION: Fourier-domain optical coherence tomography measurements showed that the retinal nerve fiber layer and macular thickness were different between methamphetamine and crystal methamphetamine abusers and healthy subjects, which should be considered in clinical practice. It seems that these drug abuses can cause alterations in retinal morphology.

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

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.

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

BACKGROUND: Beta thalassemia (ß-thalassemia) is a hereditary disease caused by defective globin synthesis and can be classified into three categories of minor (ß-TMi), intermedia (ß-TI), and major (ß-TM) thalassemia. The aim of our study is to investigate the effects of ß-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 ß-thalassemia patients undergoing chelation therapy. CONCLUSION: Ocular problems due to ß-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.

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

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.

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

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.

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

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.

Refractive errors and ocular biometry components in thalassemia major patients.

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.

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

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.

Intraocular pressure and its association with ocular biometrics in Iranian children.

PURPOSE: To determine the mean value and normative distribution of intraocular pressure (IOP) in children and their association with demographic and ocular biometrics. METHODS: Cluster sampling was done to select the students in urban areas of Shahroud, northeast Iran, while all students living in rural areas were selected. IOP was measured in mmHg using a non-contact tonometer, along with corneal and retinal imaging and ocular biometric measurement. RESULTS: After applying the exclusion criteria, 9154 eyes of 4580 students were analyzed, of whom 2377 (51.9 %) were boys. The mean age of the participants was 12.35±1.73 years (range: 9-15 years). The mean IOP was 15.58±2.83 (15.47-15.69) in total, 15.31±2.77 (15.17-15.46) in boys, and 15.88±2.86 (15.73-16.03) in girls (p < 0.001). The mean IOP was 15.07 and 15.49 in students aged 9 and 15 years, respectively. The mean IOP was 15.7 ± 2.64 (15.58-15.81) in urban and 14.52±4.05 (14.27-14.77) in rural students (p < 0.001). In the multiple generalized estimating equation model, IOP had a positive association with female sex (ß=0.84, P < 0.001), systolic blood pressure (ß=0.02, P < 0.001), cup volume (ß=0.99, P < 0.001), corneal thickness (ß=0.04, P < 0.001) and anterior chamber volume (ß=0.007, P < 0.001) and a negative association with living in the rural area (ß=-0.65, P < 0.001), rim area (ß=-0.39, P < 0.001), and corneal diameter (ß=-0.18, P = 0.045). Furthermore, individuals with myopia exhibited a significantly higher IOP (ß=0.35, P < 0.001) compared to those with emmetropia. CONCLUSION: This study showed the normative distribution of IOP and its associated factors in children. The results can be used in diagnosis and management of glaucoma.

Five-year changes in retinal nerve fibre layer thickness in the adult population: a population-based cohort study.

CLINICAL RELEVANCE: Distinguishing between the pathological thinning of the retinal nerve fibre layer (RNFL) and age-related reduction requires a comprehensive understanding of the longitudinal changes in RNFL thickness within a healthy population. BACKGROUND: To determine five-year changes in RNFL thickness and associated factors in people aged 45-69 years. METHODS: This report pertains to the second and third phases of the Shahroud Eye Cohort Study. Participants were recruited by a multi-stage cluster sampling in Shahroud, Iran. Data on demographic details, visual acuity, non-cycloplegic refraction, and slit-lamp biomicroscopy were collected. High-definition optical coherence tomography was employed for retinal imaging. RESULTS: A total of 1,524 eyes from 908 participants were examined. The average RNFL thickness was 92.2 ± 8.5 (95% CI: 91.6 to 92.8) and 93.1 ± 8.7 µm (95% CI: 92.5 to 93.7) in the first and second phases with a five-year mean change of 0.95 ± 4.15 µm (95% CI: 0.70 to 1.20). The RNFL thickness mean changes in the superior, inferior, nasal, and temporal quadrants were 2.51 ± 7.86 (95% CI: 2.01 to 3.02), 2.93 ± 7.39 (95% CI: 2.56 to 3.29), -0.53 ± 6.15 (95% CI: -0.84 to -0.21), and -1.01 ± 4.67 µm (95% CI: -1.27 to -0.75), respectively. The five-year changes in average RNFL thickness were inversely correlated with axial length (ß = -0.69, p < 0.001), mean keratometry (ß = -0.37, p = 0.017), and baseline RNFL thickness (ß = -0.617, p < 0.001). In hyperopic individuals, the increase in average RNFL thickness (ß = 0.65, p = 0.012) was significantly greater than in those with emmetropia. Macular volume (ß = 1.65, p < 0.001) showed a direct association with five-year changes in average RNFL thickness. CONCLUSION: Over 5 years, RNFL thickness changes were clinically insignificant in the normal population. The mean RNFL thickness seems to remain stable unless there is ocular disease. However, increased axial length and steeper keratometric readings were linked to RNFL thinning. Those with thicker RNFL measurements were at higher risk of thinning over time.

Axial length and anterior chamber indices in elderly population: Tehran Geriatric Eye Study.

AIM: To determine the normative distribution of axial length (AL), anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and some of their associated factors in subjects aged 60 and over. METHODS: In this cross-sectional study, 160 clusters were sampled using multi-stage cluster sampling in Tehran, Iran. After a preliminary interview, the participants underwent optometric examinations including visual acuity and refraction measurement followed by slit lamp biomicroscopy. Finally, ocular imaging was done using the Pentacam AXL to measure AL, ACD, ACV, and ACA. RESULTS: A total of 4519 eyes of 2436 participants were evaluated, of whom 58.0% (n=1412) were female. The mean age of the subjects was 67.32±6.05y (range: 60-95y). The mean AL, ACD, ACV, and ACA was 23.22 mm (23.18-23.27 mm), 2.61 mm (2.59-2.62 mm), 126.56 mm3 (125.08-128.04 mm3), and 30.61° (30.3°-30.92°), respectively. In the multivariable model, after adjusting for the effect of both eyes, the longest and shortest AL was seen in myopic and hyperopic subjects, respectively. AL, ACD, ACV and ACA were significantly larger in men compared to women (P<0.001). Except ACA, other evaluated parameters showed an inverse correlation with age (P<0.001), however, this correlation was insignificant for AL (P=0.623). CONCLUSION: Normative value of AL, and other biometric parameters are specific for each ethnicity, age and sex group. Any alteration in these parameters and their effect on refraction should be considered in this age group, especially in case of cataract surgery.

Macular Thickness and Volume by Spectral-Domain Optical Coherence Tomography and their Related Factors in the Elderly Population.

Purpose: To determine the distribution of macular thickness and macular volume in an elderly healthy population 60 years of age and above and their determinants. Methods: The sampling was performed using a multistage stratified random cluster sampling method on the geriatric population 60 years of age and above in Tehran, Iran. All participants underwent optometric examinations, slit-lamp examination, and optical biometry. Retinal imaging was performed by spectral-domain optical coherence tomography. Results: The means ± standard deviation and 95% confidence interval of central macular thickness (CMT), average macular thickness (AMT), and macular volume were 221 ± 33 (218-223) µm, 267 ± 29 (265-269) µm, and 8.36 ± 0.44 (8.33-8.39) mm3, respectively. The CMT was significantly lower in females than males (ß: -5.77; P = 0.002). The AMT was significantly lower in females than males (ß = -10.32; P < 0.001) and was significantly directly related to intraocular pressure (ß = 0.63; P = 0.038). The macular volume was significantly lower in females than males (ß = -0.13; P < 0.001) and decreased with age (ß = -0.01; P < 0.001). In addition, the macular volume had a significant inverse and direct relationship with axial length (ß = -0.04; P = 0.011) and keratometry (ß = 0.03; P < 0.001). Conclusions: Macular thickness in the Iranian geriatric population was slightly less than the populations studied in other countries. The role of sex should also be taken into account in the interpretation of macular thickness findings.

Walking Ability, Participation, and Quality of Life in Children with Spastic Diplegic Cerebral Palsy: A Path Analysis Study.

Objectives: This study aims to design a conceptual model for the effect of various factors on walking ability, participation, and quality of life in children with spastic diplegic cerebral palsy (SDCP) and test it based on field data using path analysis. Materials & Methods: This cross-sectional study was performed on 181 children with SDCP. The following were used to measure each of the variables: the Modified Ashworth Scale, the Micro Manual Muscle Tester, the Timed Up and Go Test (TUG), the Boyd and Graham test, the goniometer, weight and height, the Gross Motor Function Classification System, the Life Habits Questionnaire, and cerebral palsy Quality of Life Questionnaire for Children. The structural model was tested in Amos 17. Results: All paths of the proposed model were significant (P <0.05). Among evaluated variables, muscle strength (B = -0.466), balance (B = 0.326), and spasticity (B = 0.143) affected walking ability. Moreover, as an intermediate factor, walking ability affected the subjects' participation (B = -0.819) and quality of life (B = -0.183). Conclusion: Muscle strength, balance, and spasticity are the most influential factors in the walking ability of children with SDCP. Furthermore, walking ability and participation are two critical factors in promoting the quality of life of these children.

Optic Disc Measurements in Children by Optical Coherence Tomography.

PRCIS: This study showed the distribution of optic disc indices in a population-based sample of Iranian children in detail. Refractive errors and biometric components are among the ocular factors that are related to these indices. PURPOSE: To determine the normative value of optic nerve indices in children and their association with ocular and demographic factors. METHODS: A cross-sectional study was conducted in 2018. Biometry was done using the Allegro Biograph, and macular indices were measured by OCT imaging. RESULTS: After applying the exclusion criteria, 9051 eyes of 4784 children were analyzed. The mean±SD and 95% confidence intervals (in parentheses) of vertical cup-to-disc ratio, average cup-to-disc ratio, rim area, disc area, and cup volume were 0.45±0.15(0.45-0.46) mm, 0.43±0.14 (0.42-0.43) mm, 1.46±0.25 (1.45-1.47) mm 2 , 1.92±0.35 (1.91-1.93) mm 2 , and 0.14±0.14 (0.14-0.15) mm 3 , respectively. Vertical cup-to-disc ratio and average cup-to-disc ratio had a positive association with intraocular pressure (IOP) (both ßs=0.003), and a negative association with retinal nerve fiber layer thickness (both ßs=-0.001), central corneal thickness (CCT) (both ßs=-0.001), anterior chamber depth (ß=-0.025 and ß=-0.027, respectively), lens thickness (ß=-0.034 and ß=-0.032, respectively), and mean keratometry (MK) (both ßs=-0.015). The average cup-to-disc ratio had a positive association with height (ß=0.001). Rim area had a negative association with increased age (ß=-0.008), axial length (ß=-0.065), IOP (ß=-0.009), and MK (ß=-0.014) and a positive association with macular volume (ß=0.021), retinal nerve fiber layer thickness (ß=0.004), and CCT (ß=0.001). Disc area had a positive association with macular volume (ß=0.031) and a negative association with female sex (ß=-0.037), axial length (ß=-0.087), anterior chamber depth (ß=-0.112), lens thickness (ß=-0.059), and MK (ß=-0.048). The results of generalized estimating equations showed that cup volume was smaller in girls (ß=-0.009), and had a positive association with height (ß=0.001), IOP (ß=0.003) and negative association with CCT (ß=-0.0001) and MK (ß=-0.012). CONCLUSION: The results provided the normative values of optic disc indices in children. Demographic factors, biometric components, IOP, SBP, and retinal parameters had a significant association with optic disc indices.

Epidemiological aspect of retinoblastoma in the world: a review of recent advance studies.

AIM: To collect and present updated evidence about epidemiological aspects of retinoblastoma (Rb) in the world. METHODS: A comprehensive search without the time and language restrictions was conducted in international databases, including MEDLINE, Scopus, Web of Science, and PubMed. The search keywords were "retinoblastoma" OR "retinal Neuroblastoma" OR "retinal glioma" OR "retinoblastoma eye cancer" OR "retinal glioblastoma". RESULTS: The worldwide incidence of Rb is 1 in 16 000-28 000 live births, but was higher in developing compared to developed countries. Several attempts for improving early detection and treatment had increased the Rb survival rate from 5% to 90% in developed countries over the past decade, but its survival was lower in developing countries (about 40% in low-income countries) and the majority of mortalities occurred in developing countries. The etiology of Rb could be viewed as genetics in the heritable form and environmental and lifestyle factors in the sporadic form. Some environmental risk factors such as in vitro fertilization; insect sprays; father's occupational exposure to oil mists in metal working, and poor living conditions might play a role in the occurrence of the disease. Although ethnicity might affect Rb incidence, sex has no documented effect and the best treatment approaches were now ophthalmic artery chemosurgery and intravitreal chemotherapy. CONCLUSION: Determining the role of genetics and environmental factors helps to accurately predict the prognosis and identify the mechanism of the disease, which can reduce the risk of tumor development.

Distribution and associated factors of intraocular pressure in the older population: Tehran Geriatric Eye Study.

AIM: To determine the distribution and associated factors of intraocular pressure (IOP) in an Iranian elderly population 60 years of age and above. METHODS: The present report is part of the Tehran Geriatric Eye study (TGES), a population-based cross-sectional study that was conducted on the residents of Tehran 60 years of age and above. The sampling was performed using multistage stratified random cluster sampling methods from 22 districts of Tehran, Iran. Demographic and history information, blood samples, and blood pressure were collected from all participants. Ocular examinations included measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, and slit-lamp biomicroscopy. The IOP was measured using Goldmann applanation tonometry (GAT). Corneal imaging and ocular biometry were performed using Pentacam AXL. RESULTS: The data of 3892 eyes of 2124 individuals were analyzed for this report. The mean age of the study participants was 66.49±5.31y (range: 60 to 95y). The mean IOP was 15.2 mm Hg (95%CI: 15.1 to 15.4), 15.3 mm Hg (95%CI: 15.1 to 15.5) and 15.1 mm Hg (95%CI: 15.0 to 15.3) in all participants, males, and females, respectively. Of the study participants, 1.3% had an IOP of ≥20 mm Hg. The mean IOP increased from 15.1 mm Hg in the age group 60-64y to 16.3 mm Hg in the age group ≥80y. According to the final multiple GEE model, the IOP was statistically significantly higher in men than in women. All the studied age groups, except for the 75-79-year-old age group, had significantly higher IOP compared to the 60-64-year-old age group. The IOP was significantly higher in underweight compared to other body mass index groups. Moreover, the IOP had a statistically significant direct relationship with the mean corneal power (mean CP), central corneal thickness (CCT), and systolic blood pressure. CONCLUSION: The present study presents the distribution of IOP in an Iranian elderly population. A higher IOP (within the range 14 to 17 mm Hg) is significantly associated with older age, male sex, high systolic blood pressure, increased mean CP, and CCT. These factors should be considered in the clinical interpretation of IOP.

Evaluation of the frequency of ABO and Rh-Hr blood-group systems in different acquired cataracts type.

OBJECTIVES: This study evaluated the relationship between acquired cataract's different types and the ABO and Rh blood classes. METHODS: Overall, 520 patients, by randomized sampling method, participated in this retrospective cross-sectional study. After reviewing the patient's medical records and laboratory results, the patient's demographics, ABO group, Rh, and cataract type were documented. RESULTS: A total of 520 patients were included in the research, with a mean age of 67.57 ± 11.85. Most of them were female (n = 286, 55%). Mix (n = 230, 44%) and nuclear sclerotic (NS) (n = 167, 32%) cataracts were the most common types. The posterior subcapsular cataract (PSC) prevalence in females was significantly higher than in males (16.1% vs.7.3% p = 0.002). Also, men had more NS cataracts than females (89, 38% vs. 78, 27.3%) (p = 0.009). Patients with PSC were significantly younger than others (all p-values < 0.001). Our results showed that cataract types are independent of blood group types and Rh (P > 0.05). CONCLUSION: Although our findings showed that cataract types are independent of blood group types and Rh, they can be compared with future studies on the association of other Blood-Group Systems in developing acquired cataracts.