Prevalence of Certain Corneal Conditions and their Demographic Risk Factors; Tehran Geriatric Eye Study.

BACKGROUND: Corneal abnormalities are one of the important reasons for visual impairment. There is little evidence of the prevalence of different types of corneal abnormalities. The aim of this study was to assess the prevalence of various corneal abnormalities and identify the key risk factors associated with these abnormalities in an elderly population residing in Tehran. METHODS: The Tehran Geriatric Eye Study (TGES) was conducted as a cross-sectional study, utilizing a population-based approach and employing stratified cluster random sampling. The study focused on individuals aged 60 years and above residing in Tehran. An ophthalmologist performed a slit lamp examination to evaluate the eyelid, cornea, and crystalline lens. RESULTS: The prevalence of posterior embryotoxon (PE), punctate epithelial defect (PED), pigment on endothelium (POE), corneal dystrophy (CDys), corneal vascularization (CV), and corneal degeneration (CDeg) were estimated to be 0.08% (95% confidence interval [CI]: 0.02 to 0.40), 8.77% (95% CI: 6.64 to 11.51), 0.57% (95% CI: 0.33 to 0.98), 0.53% (95% CI: 0.33 to 0.82), 0.95% (95% CI: 0.60 to 1.52), and 44.87% (95% CI: 41.80 to 47.98), respectively. Overall, approximately 49.08% of the participants exhibited some form of corneal abnormality in at least one eye. The multiple logistic regression model revealed that increasing age was significantly associated with PED, CV, and CD. Furthermore, illiterate participants had a significantly higher prevalence of PE. CONCLUSION: The findings of this study indicate that approximately half of the elderly population aged 60 years and above in Tehran have at least one corneal abnormality, with corneal degeneration being the most prevalent. Age was identified as the primary determinant of corneal abnormalities.

Comparison of the accommodative amplitude measured with and without the use of a specialised accommodative rule in children.

OBJECTIVE: To determine the agreement between measurements of accommodative amplitude (AoA) in children using a specialised accommodative rule and measurments without it. METHODS: A total of 502 children underwent optometric examinations, including the measurement of visual acuity, objective and subjective refraction. AoA measurements were done with and without the Berens accommodative rule. The measurements of AoA were conducted monocularly using a -4 D lens. A fixation stick containing English letters equivalent to 20/30 visual acuity and a long millimetre ruler was used to measure AoA without the accommodative rule. This measurement was performed by the two trained examiners. The agreement between these methods was reported by 95% limits of agreement (LoA) and interclass correlation coefficient (ICC). RESULTS: The mean age of the participants was 11.7±1.3 years (range: 9-15 years) and 52.4% were male. The mean AoA with and without the accommodative rule was 20.02±6.02 D and 22.46±6.32 D, respectively. The 95% LoA between the two methods was -12.5 to 7.5 D, and the ICC was 0.67 (95% CI 0.63 to 0.70). The 95% LoA was narrower in higher age groups and males compared with females (18.92 vs 20.87). The 95% LoA was narrower in hyperopes (16.83 D) compared with emmetropes (18.37 D) and myopes (18.27 D). The agreement was not constant and decreased in higher values of AoA. CONCLUSION: There is a poor and non-constant agreement between the measurements of the AoA with and without the accommodative rule. The mean AoA was 2.5 D lower with using the accommodative rule.

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.

Distribution and associated factors of keratometry and corneal astigmatism in an elderly population.

To determine the distribution of keratometry and corneal astigmatism (CA) and their association with demographic factors, systemic parameters, anthropometric measures, ocular biometric indices, and refractive errors in people aged 60 years and above. In this cross-sectional study, 160 clusters were randomly selected from Tehran city (Iran) using the multi-stage cluster sampling method. All participants underwent optometric examinations including testing uncorrected and best-corrected distance visual acuity, non-cycloplegic autorefraction, and subjective refraction. Pentacam imaging for all participants was carried out using Pentacam AXL. Keratometry and CA were reported based on Pentacam's data. The average, standard deviation (SD) and 95% confidence interval (CI) of flat keratometry (Kf), steep keratometry (Ks), mean keratometry (mean K), and CA were 44.02 ± 1.58 D (95% CI 43.94-44.1), 44.86 ± 1.67 D (95% CI 44.78-44.94), 44.44 ± 1.58 D (95% CI 44.36-44.52), and 0.84 ± 0.74 D (95% CI 0.81-0.87), respectively. The 95% and 99% percentiles of mean K were 47.1 and 48.6 D, respectively. According to the multiple generalized estimating equation model, the mean K was significantly higher in males, in myopes, and in those with higher systolic blood pressure. Moreover, the mean K was inversely related to the axial length, height, anterior chamber depth (ACD), corneal diameter, and central corneal thickness (CCT). The prevalence of various types of CA based on a cut-off > 0.50 D was as follows; with-the-rule: 32.5% (95% CI 30.6-34.4), against-the-rule: 18.2% (95% CI 16.7-19.7), and oblique: 10.0% (95% CI 9.1-11.0). The present study investigated the normal distribution of keratometry and CA in individuals ≥ 60 years, and results can be used in clinical matters, especially in intraocular lens power calculation. Sex, systolic blood pressure, height, and some biometric components such as ACD, corneal diameter, and CCT were significantly related to keratometry and should be considered.

Analysis of macular thickness and peripapillary retinal nerve fiber layer thickness in various ABO and Rh blood groups.

PURPOSE: To determine the association between ABO and Rh blood groups with retinal structural indices including macular thickness and peripapillary retinal nerve fiber layer (RNFL) thickness. METHODS: This cross-sectional study was conducted using convenience sampling in a tertiary referral eye hospital in Tehran, Iran. Study participants were referred to the hospital laboratory to test their blood group. Ocular examinations were performed including measurement of visual acuity, auto-refraction, subjective refraction, and slit-lamp biomicroscopy. Retinal imaging was carried out using Spectral-domain OCT under dilated papillary conditions. RESULTS: Three hundred and twenty-eight individuals were recruited in this study. Of these, 219 (60.7%) were female and the mean age of the participants was 63.29 ± 5.57 years (range: 56 to 83 years). According to the multiple linear regression model, the global peripapillary RNFL thickness [coefficient: -3.05 (95% CI: -5.30 to -0.74); P = 0.010] and peripapillary RNFL thickness in the superior [coefficient: -4.65 (95% CI: -8.40 to -0.89), P < 0.001] and inferior [coefficient: -4.00 (95% CI: -7.81 to -0.19); P = 0.040] quadrants were significantly thinner in individuals with blood type B compared to those with other ABO blood groups. The average [coefficient: 12.69 (95% CI: 4.12-21.64); P = 0.004) and central [coefficient: 16.21 (95%: 6.44-25.97); P = 0.001) macular thicknesses were significantly thicker in AB group compared to other blood groups. The average macular thickness was significantly thinner in Rh + compared to the Rh- group [coefficient: -8.33 (95% CI: -15.4 to -1.25); P = 0.021]. CONCLUSION: Retinal structural indices may be related to blood groups implying a genetic linkage. Considering the lack of consistency among various studies, larger trials are needed to explore the effect of ABO and Rh grouping on peripapillary RNFL and macular thicknesses.

Applications of Artificial Intelligence in Diagnosis of Dry Eye Disease: A Systematic Review and Meta-Analysis.

PURPOSE: Clinical diagnosis of dry eye disease is based on a subjective Ocular Surface Disease Index questionnaire or various objective tests, however, these diagnostic methods have several limitations. METHODS: We conducted a comprehensive review of articles discussing various applications of artificial intelligence (AI) models in the diagnosis of the dry eye disease by searching PubMed, Web of Science, Scopus, and Google Scholar databases up to December 2022. We initially extracted 2838 articles, and after removing duplicates and applying inclusion and exclusion criteria based on title and abstract, we selected 47 eligible full-text articles. We ultimately selected 17 articles for the meta-analysis after applying inclusion and exclusion criteria on the full-text articles. We used the Standards for Reporting of Diagnostic Accuracy Studies to evaluate the quality of the methodologies used in the included studies. The performance criteria for measuring the effectiveness of AI models included area under the receiver operating characteristic curve, sensitivity, specificity, and accuracy. We calculated the pooled estimate of accuracy using the random-effects model. RESULTS: The meta-analysis showed that pooled estimate of accuracy was 91.91% (95% confidence interval: 87.46-95.49) for all studies. The mean (±SD) of area under the receiver operating characteristic curve, sensitivity, and specificity were 94.1 (±5.14), 89.58 (±6.13), and 92.62 (±6.61), respectively. CONCLUSIONS: This study revealed that AI models are more accurate in diagnosing dry eye disease based on some imaging modalities and suggested that AI models are promising in augmenting dry eye clinics to assist physicians in diagnosis of this ocular surface condition.

The Effect of Cycloplegia on Ocular Alignment and AC/A Ratio.

Purpose: The present study sets out to investigate the effect of cyclopentolate-induced cycloplegia on distance and near deviation and the accommodative convergence/accommodation (AC/A) ratio. Methods: This prospective study was performed on 30 subjects. The inclusion criteria included a lack of any active ocular pathology and systemic diseases, no history of ocular surgery, and nonuse of various medications. Refraction, near and distance deviation were measured for all subjects, and the same examinations were repeated after the administration of two drops of cyclopentolate 1% to both eyes. Results: The obtained data from 30 subjects, including 19 males, with a mean age of 22.53 ± 1.74 years were analyzed. The mean ± SD of near deviation in dry and cycloplegic conditions were -6.9 ± 8.1 and +6.4 ± 9.1 prism diopters, respectively, which were statistically significant (P < 0.001). Distance deviation in cycloplegic conditions demonstrated an average difference of 0.8 prism diopters, compared to dry conditions (P < 0.001). AC/A ratios were 4.7 ± 2.5 and 9.7 ± 3.9 (Δ/D) in non-cycloplegic and cycloplegic conditions, respectively, which was a statistically significant difference (P < 0.001). The multiple regression indicated that among all under study variables, refraction (B coefficient: -2.4; P < 0.001) and near pre-cycloplegic deviation (B coefficient: 0.56; P < 0.001) were significantly associated with post-cycloplegic near deviation. Conclusion: The results of this study indicated that cycloplegia causes a considerable esophoric shift in near deviation and a negligible esophoric shift in distance deviation. As a result, the AC/A ratio demonstrated a significant increase due to unequal changes in near and distance deviation.

Prevalence of retinal pathologies in people over 60 years: the Tehran Geriatrics Eye Study.

AIM: To determine the prevalence of some retinal pathologies in people over 60y and their association with demographic and ocular factors. METHODS: A cross-sectional study was conducted in Tehran using multistage cluster sampling. After selecting subjects aged 60 and over, optometric, and ophthalmic examinations were done. For retinal examination, a 90 D lens was used and indirect ophthalmoscopy was performed after instilling tropicamide drops. Biometry was done using the IOL Master for all participants. RESULTS: Of 3791 people that were invited through cluster sampling, 3310 participated in the study (response rate=82%). The prevalence of retinal pigmented epithelium (RPE) change, drusen, geographic atrophy (GA), hypertensive retinopathy (HTR), nonproliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), choroidal neovascularization (CNV), central retinal artery occlusion (CRAO), myopic retinopathy (MR), branch retinal vein occlusion (BRVO), and central retinal vein occlusion (CRVO) was 27.42%, 11.08%, 4.52%, 3.03%, 4.05%, 0.54%, 0.82%, 0.39%, 0.20%, 0.49%, and 0.19%, respectively. After removing the effect of age, the odds of NPDR were 1.68 times higher in women compared to men (P=0.014). After removing the effect of sex, the odds of drusen, RPE change, GA, CNV, BRVO, and CRVO increased with age. CONCLUSION: There is a higher prevalence of RPE change, drusen, GA, CNV and a lower prevalence of MR and CRAO in the elderly population of Tehran aged over 60y compared to global average values. Considering the correlation of most of the diseases with age and their effects on vision, attention should be paid to these diseases and the related screening programs to prevent vision impairment.

Subfoveal choroidal thickness in a general elderly population; Tehran geriatric eye study.

PURPOSE: To determine the distribution of subfoveal choroidal thickness (SFCT) and its associated demographic, ocular, and systemic factors in an elderly population. METHODS: This report is part of the Tehran Geriatric Eye Study (TGES); a population-based cross-sectional study that was conducted on the urban elderly population of Tehran, aged 60 years and above using multi-stage stratified random cluster sampling. Choroidal imaging was performed using Spectralis SD-OCT with enhanced depth imaging mode. RESULTS: The average SFCT was 265.3 ± 25.9 µm (95% CI: 262.8-267.7) in the whole sample. According to the multiple generalized estimating equation (GEE) model, pseudophakia had a statistically significant direct relationship with SFCT (coefficient = 5.69), and history of cerebrovascular accident (CVA) was significantly inversely related to SFCT (coefficient=-4.77). Moreover, there was a significant interaction between age and sex in the average SFCT so that with increasing age, the SFCT increased in men and decreased in women. CONCLUSION: The normal values of SFCT in the present study can be used as a reference database for clinical and research purposes. Age-sex interaction, pseudophakia, and history of CVA were significantly associated with SFCT in the elderly population. It is recommended that these factors be taken into account when interpreting SFCT data.

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.

The association between iris color and refractive errors in children.

This study aimed to evaluate the association between iris color and refractive errors in children aged 6-12 years. This cross-sectional study was based on data obtained from the first phase of the Shahroud Schoolchildren Eye Cohort Study. The target population was 6 to12 year-old students living in urban and rural areas. Iris colors were classified by comparing eye colors with close-up images of iris colors. Myopia was defined as a spherical equivalent (SE) ≤ - 0.5 diopter and hyperopia was defined as SE ≥ 2 diopter in cycloplegic refraction. The association of iris color with hyperopia and myopia was investigated by fitting two separate multiple logistic regression models adjusted for place of residence, age, sex, and times for outdoor activity and near work. Among the 5394 participates with the mean age of 9.7 year, the prevalence of myopia and hyperopia was 4.8% and 4.7% respectively. The number and proportion (in parentheses) of amber, light blue, light brown, dark brown, gray, green and hazel iris colors were 19(0.4%), 26(0.5%), 645(12.0%), 4517(83.7%), 4(0.1%), 59(1.1%), and 124(2.3%) respectively. Compared to dark brown, the odds ratios and 95% confidence intervals (in parentheses) of myopia were 4.8(1.2-18.7), 0.8(0.1-5.8), 1.0(0.7-1.5), 0.4(0.1-2.7) and 0.6(0.2-1.8) for amber, light blue, light brown, green and hazel iris colors in multiple logistic regression model. No significant association was observed between iris colors and hyperopia. This study shows that amber iris is significantly associated with higher odds of myopia. These children should be further monitored and examined. More studies with higher sample size in all iris colors are recommended.

The association between visual impairment and mental disorders.

To determine the association between visual impairment (VI) and some mental disorders using the general health questionnaire (GHQ) in individuals aged 60 years and above in Tehran, Iran. The present population-based cross-sectional study was conducted on people aged 60 and older in Tehran, Iran using multi-stage cluster sampling. After selecting the samples, examinations including visual acuity measurement, refraction, and slit-lamp biomicroscopy were performed for all participants. The GHQ was used to examine mental disorders. Simple and multiple linear regressions were used to investigate the association between VI and mental disorders. Of the 3740 invitees, 3310 participated in the study (response rate: 88.50%). After applying the exclusion criteria, 2789 individuals were analyzed for this report. Mean score of physical, anxiety, social and depression disorders in people with and without VI was 3.74 ± 2.03, 5.81 ± 2.79, 7.56 ± 1.91, 1.32 ± 1.90, and 3.14 ± 1.76, 4.93 ± 2.71, 8.09 ± 1.99, 0.91 ± 1.38, respectively. The total score of GHQ in participants with and without VI was 18.43 ± 4.75 and 17.07 ± 4.19, respectively. The association between GHQ subscales and total GHQ score with VI by multiple linear regression showed that VI had a statistically significant direct association with physical symptoms (ß = 0.37; 95% CI 0.12 to 0.62) and anxiety (ß = 0.48; 95% CI 0.16 to 0.81). Nevertheless, depression had a borderline association with VI (ß = 0.21; 95% CI - 0.03 to 0.45) and social dysfunction did not have a statistically significant association with VI in the final linear regression model and did not remain in the model. Total GHQ score had a statistically significant association with VI (ß = 1.02; 95% CI 0.39 to 1.64) in the presence of covariates. Regarding the association between VI and GHQ components, the physical symptoms had the highest R2 (R2 = 0.159). Patients with VI suffer more from anxiety, depression, and physical symptoms regardless of age, sex, education, and other effective variables. The coincidence of aging with VI and the association of VI with mental disorders emphasizes the importance of a broader view of the elderly and the aging process.

Prevalence of anisometropia and its associated factors in school-age children.

PURPOSE: To determine the prevalence of anisometropia and the associated demographic and biometric risk factors in children. METHODS: This cross-sectional study was conducted on the elementary school children of Shahroud, east of Iran, in 2015. All rural students were recruited, while multistage cluster sampling was used to select the students in urban areas. All children underwent optometric examinations including the measurement of uncorrected and corrected visual acuity, autorefraction, and subjective refraction with cycloplegia. Biometric components were measured using the Allegro Biograph. Myopia and hyperopia were defined as a spherical equivalent ≤-0.5 and ≥ +2.00 diopter, respectively. Students with a history of ocular trauma or lack of cycloplegic refraction at least in one eye were excluded from the study. RESULTS: Of 6624 selected children, 5620 participated in the study. After applying the exclusion criteria, the data of 5357 students (boys: 52.8%, n = 2834) were analyzed. The mean age of the subjects was 9.2 ± 1.7 years (range: 6-12 years). The prevalence of anisometropia ≥ 1 D was 1.1% (95% CI: 0.8 to 1.4) in all children, 1.0% (95% CI: 0.7-1.3) in boys, 1.3% (95% CI: 0.8-1.7) in girls, 1.1% (95% CI: 0.8-1.4) in urban children, and 1.4% (95% CI: 0.5-2.3) in rural children. The prevalence of anisometropia was 8.8% (95% CI: 5.3-12.2) in myopic and 5.7% (95% CI: 2.8-8.5) in hyperopic children. Axial length asymmetry (OR = 40.9; 95%CI: 10.2-164.1), myopia (OR = 17.9; 95% CI: 9.4-33.9), and hyperopia (OR = 10.1; 95% CI: (5.1-19.7) were associated with anisometropia in multiple logistic regression model. More anisometropia was associated with more severe amblyopia. The odds of amblyopia (OR = 82.3: 38.2-177-3) and strabismus (OR = 17.6: 5.5-56.4) were significantly higher in anisometropic children. The prevalence of amblyopia was 21.7% in children with myopic anisometropia ≥ 3D, 66.7% in children with hyperopic anisometropia ≥ 3D, and 100% in cases with antimetropia ≥ 3D. CONCLUSION: The prevalence of anisometropia was low in Iranian school children. However, a high percentage of anisometropic students had amblyopia and strabismus. Axial length was the most important biometric component associated with anisometropia.

Mean cycloplegic refractive error in emmetropic adults - The Tehran Eye Study.

PURPOSE: In children under 20 years, refractive development targets a cycloplegic refractive error of +0.5 to +1.5D, while presbyopes over 40 years generally have non-cycloplegic errors of ≥ +1D. Some papers suggest these periods are separated by a period of myopic refractive error (i.e., ≤ -0.50D), but this remains unclear. Hence, this work investigates the mean cycloplegic refractive error in adults aged between 20 - 40 years. METHODS: In 2002 a cross-sectional study with stratified cluster sampling was performed on the population of Tehran, providing cycloplegic and non-cycloplegic refractive error data for the right eyes of 3,576 participants, aged 30.6±18.6 years (range: 1-86 years). After grouping these data into age groups of 5 years, the refractive error histogram of each group was fitted to a Bigaussian function. The mean of the central, emmetropized peak was used to estimate the mean refractive error without the influence of myopia. RESULTS: The mean cycloplegic refractive error at the emmetropized peak decreased from +1.10±0.11D (95 % confidence interval) to +0.50±0.04D before 20 years and remains stable at that value until the age of 50 years. The non-cycloplegic refractive error also sees a stable phase at 0.00±0.04D between 15 - 45 years. After 45 - 50 years both cycloplegic and non-cycloplegic refractive error become more hypermetropic over time, +1.14±0.12D at 75 years. CONCLUSIONS: The cycloplegic refractive error in adults is about +0.50D between 20 - 50 years, disproving the existence of the myopic period at those ages.

Applications of SMILE-extracted lenticules in ophthalmology.

AIM: To review recent innovations, challenges, and applications of small incision lenticule extraction (SMILE) extracted lenticule for treating ocular disorders. METHODS: A literature review was performed in the PubMed database, which was last updated on 30 December 2021. There was no limit regarding language. The authors evaluated the reference lists of the collected papers to find any relevant research. RESULTS: Due to the simplicity and accuracy of modern femtosecond lasers and the extensive development of SMILE surgery, many healthy human corneal stromal lenticules were extracted during surgery, motivating some professionals to investigate the SMILE lenticule reusability in different ocular disorders. In addition, new approaches had been developed to preserve, modify, and bioengineer the corneal stroma, leading to the optimal use of discarded byproducts such as lenticules from SMILE surgery. The lenticules can be effectively re-implanted into the autologous or allogenic corneas of human subjects to treat refractive errors, corneal ectasia, and corneal perforation and serve as a patch graft for glaucoma drainage devices with better cosmetic outcomes. CONCLUSION: SMILE-extracted lenticules could be a viable alternative to human donor corneal tissue.

Comparison of different corneal imaging modalities using artificial intelligence for diagnosis of keratoconus: a systematic review and meta-analysis.

PURPOSE: This review was designed to compare different corneal imaging modalities using artificial intelligence (AI) for the diagnosis of keratoconus (KCN), subclinical KCN (SKCN), and forme fruste KCN (FFKCN). METHODS: A comprehensive systematic search was conducted in scientific databases, including Web of Science, PubMed, Scopus, and Google Scholar based on the PRISMA statement. Two independent reviewers assessed all potential publications on AI and KCN up to March 2022. The Critical Appraisal Skills Program (CASP) 11-item checklist was used to evaluate the validity of the studies. Eligible articles were categorized into three groups (KCN, SKCN, and FFKCN) and included in the meta-analysis. The pooled estimate of accuracy (PEA) was calculated for all selected articles. RESULTS: The initial search yielded 575 relevant publications, of which 36 met the CASP quality criteria and were included in the analysis. Qualitative assessment showed that Scheimpflug and Placido combined with biomechanical and wavefront evaluations improved KCN detection (PEA, 99.2, and 99.0, respectively). The Scheimpflug system (92.25 PEA, 95% CI, 94.76-97.51) and a combination of Scheimpflug and Placido (96.44 PEA, 95% CI, 93.13-98.19) had the highest diagnostic accuracy for the detection of SKCN and FFKCN, respectively. The meta-analysis outcomes showed no significant difference between the CASP score and accuracy of the publications (all P > 0.05). CONCLUSIONS: Simultaneous Scheimpflug and Placido corneal imaging methods provide high diagnostic accuracy for early detection of keratoconus. The use of AI models improves the discrimination of keratoconic eyes from normal corneas.

Longitudinal changes in crystalline lens thickness and power in children aged 6-12 years old.

OBJECTIVES: To determine the three-year changes in crystalline lens power (LP) and thickness (LT) in children and their associated factors. METHODS: Schoolchildren aged 6-12 years living in Shahroud, northeast Iran were examined in 2015 and 2018. The Bennett formula was used to calculate LP. Multiple generalized estimating equations (GEE) analysis was used for data analysis. RESULTS: Among the 8089 examined eyes, the mean LP in Phase 1 and 2, and the three-year change were 21.61 ± 1.47D, 21.00 ± 1.42D, and -0.61 ± 0.52D, respectively. The GEE model showed that negative shifts in LP were less pronounced with increasing age (ß = 0.176; p < 0.001), and were also less noticeable in hyperopes compared to emmetropes (ß = 0.120; p < 0.001). The changes in LP decreased when outdoor activity increased among urban residents (ß = 0.013; p = 0.039), while it increased in rural area (ß = -0.020; p = 0.047). Mean three-year change in LT was 0.002 ± 0.13 mm. Female sex and aging by one year increased the LT by 0.022 mm (P < 0.001). However, LT decreased in 6-8-year-olds, while it increased in 10-12-year-old children, both in a linear fashion. The change in LT was less in myopes than in emmetropes (ß = -0.018, P-value = 0.010). CONCLUSION: LP decreases after three years in 6 to 12-year-old children. LT increases slightly after three years in 6 to 12-year-old children. The changes in LP and LT were associated with the refractive errors, place of residence, age and gender and outdoor activity time.

Prevalence and Associated Factors of Pseudoexfoliation Syndrome in an Iranian Elderly Population: The Tehran Geriatric Eye Study.

PURPOSE: To investigate the prevalence and associated factors of pseudoexfoliation syndrome (PEX) in an Iranian elderly population. METHODS: This study, a population-based cross-sectional study conducted on individuals ≥60 years in Tehran, the capital of Iran in 2019 using a multi-stage stratified random cluster sampling. All study participants underwent complete ocular examination (including measurement of uncorrected and best-corrected visual acuity, refraction, slit-lamp biomicroscopy). The PEX was diagnosed based on the presence of white fluffy dandruff-like pseudoexfoliative material on the pupillary margin, on the anterior lens capsule, and/or the trabecular meshwork. RESULTS: Of the 3791 invitees, 3310 participated in the TGES (response rate: 87.3%). After applying exclusion criteria, the data of 3274 individuals were analyzed for this report. The overall prevalence of PEX was 3.63% (95% CI:2.67-4.58) in this study. 81.1% of PEX cases were bilateral. The prevalence of PEX increased significantly with advancing age in a linear trend from 2.38% (95%: 1.27-3.48) in the age group 60-64 years to 6.48% (95%: 2.02-10.95) in the age group ≥80 years (OR = 1.05, p = 0.008). According to the multiple logistic regression model, advancing age (OR: 1.06, p = 0.002) and the presence of cataract (OR: 5.02, p < 0.001) were significantly associated with increased odds of PEX. CONCLUSION: The results showed a lower prevalence of PEX in the Iranian elderly compared to previous studies on the elderly population. Advancing age and cataracts were the only associated factors of PEX in the present study.

Agreements' profile of Scheimpflug-based optical biometer with gold standard partial coherence interferometry.

AIM: To determine the agreement of ocular biometric indices including axial length, keratometric readings, anterior chamber depth, and horizontal corneal diameter between the Pentacam AXL and IOL Master 500. METHODS: The study was a large cross-sectional population-based study (Tehran Geriatric Eye Study) conducted from Jan 2019 to Jan 2020. A total of 160 clusters were randomly selected proportional to size (each cluster contained 20 individuals) from 22 strata of Tehran city. All people aged 60y and above were invited to participate in the study. For all participants, preliminary ocular examinations were performed including the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, anterior and posterior segment examinations. All participants underwent an ocular biometry using the Pentacam AXL and IOL Master 500. RESULTS: The 95% limits of agreement (LoA) between the two devices were -0.13 to 0.19, -0.15 to 0.17, and -0.13 to 0.19 in normal, pseudophakic, and cataractous eyes, respectively. With increasing the axial length, the difference between the two devices significantly increased in all three groups of normal, pseudophakic, and cataractous eyes (P<0.001). The 95% LoAs between the two devices regarding the mean keratometry shows that the best LoAs were seen in cataractous (-0.33 to 0.81) and followed by normal eyes (-0.36 to 0.86) and the pseudophakic eyes (-0.48 to 0.90) had the widest LoA. The 95% LoAs for horizontal corneal diameter measurements were -0.08 to 0.86, -0.03 to 0.83, and -0.07 to 0.87 in normal, pseudophakic, and cataractous eyes, respectively. The 95% LoAs of anterior chamber depth measurements between the two devices was -0.39 to 0.19 and -0.37 to 0.13 in normal eyes and cataractous, respectively. CONCLUSION: The Pentacam AXL has excellent agreement with the gold standard, IOL Master 500 in measuring axial length. In eyes with cataracts, the difference between the two devices is more scattered. With the increasing of axial length, the difference between the two devices increased, which should be considered when using Pentacam AXL.

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.