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The aim of this study was to assess and compare clinical characteristics of bilateral keratoconus patients with unilateral Vogt's striae. In this contralateral eye study, refractive status were evaluated in patients with bilateral keratoconus whose corneas had definite slit-lamp biomicroscopic evidence of unilateral Vogt's striae. All cases underwent a comprehensive ophthalmic examination. Some refractive errors components provided by autorefraction were converted to vectorial notation for power vector analysis. Finally, the outcomes were compared between keratoconus eyes with and without Vogt's striae. Fifty patients aged 20 to 38 years (27.43 ± 5.5) were recruited in this study. The results showed a significant difference in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), non-cycloplegic and cycloplegic autorefraction including sphere, cylinder, spherical equivalent, and J 0 , between keratoconus eyes with and without Vogt's striae (all P < 0.05), except for J 45 (P = 0.518 in non-cycloplegic autorefraction and P = 0.574 in cycloplegic autorefraction). Comparison of cycloplegic and non-cycloplegic autorefraction in both study groups showed significant differences in the sphere and spherical equivalent (all P < 0.001), but no significant difference was found in cylinder, J 0 , and J 45 between the study groups (all P > 0.05). Comparison of the cycloplegic and non-cycloplegic autorefraction in keratoconus eyes with and without Vogt's striae showed significant differences in UDVA, CDVA, and some refractive errors components provided by autorefraction between the two groups, with a worse condition in KCN eyes with Vogt's striae. [ABSTRACT FROM AUTHOR]

To determine the prevalence of astigmatism and its determinants in schoolchildren aged 6–12 years. The students selected by stratified cluster random sampling in Shahroud, north of Iran. Optometric examination included uncorrected visual acuity, refraction with autorefractometer, manifest refraction with retinoscopy followed by subjective and cycloplegic refraction (after two drops of cyclopentolate 1% with 5 min interval were instilled in each eye). A cylinder power ≥0.75 diopter (D) in at least one eye was considered as astigmatism. The prevalence of astigmatism was reported based on a cylinder power higher than 0.50, 1.00, and 2.00 D in cycloplegic refraction, followed by power vector analysis. After applying the inclusion criteria, the data of 5528 children were analyzed. The prevalence of astigmatism was 16.7% (95% CI: 15.6–17.7) in total, 16.6% (95% CI: 15.2–18.0) in boys and 16.8% (95% CI: 15.2–18.3) in girls (p = 0.920) and decreased from 21.5% in 6-year-old children to 13.7% in 10-year-olds, and then again increased to 18.3% in children aged 12 years. Moreover, 17.2% (95% CI: 16.0–18.3) of urban and 12.1% (95% CI: 10.0–14.1) of rural children had astigmatism (p < 0.001). The prevalence of with-the-rule, against-the-rule, and oblique astigmatism was 14.2%, 2.1%, and 0.33%, respectively. The mean cylinder power was −1.31, −0.46, and −0.44 D in children with spherical myopia, emmetropia, and hyperopia, respectively (p < 0.001). Urban students had a higher J 0 and boys had a higher J 45. The prevalence of astigmatism in this study was lower than previous studies. Astigmatism prevalence was markedly higher in urban children. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Optometry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Optometry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Optometry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: Welders are prone to ocular injuries and ocular surface problems due to exposure to ultraviolet light. The aim of this study was to evaluate the tear film comprehensively and assess objective and subjective indices of dry eye in welders.Methods: In this historical cohort, welders with at least 5 years of experience were compared with controls. A complete evaluation of ocular health was done for all participants. The Schirmer test (invasive and non-invasive) and Invasive Tear Break-Up Time (ITBUT) were applied for objective evaluation and the Ocular Surface Disease Index (OSDI) was used for subjective assessment of the tear film status. The results were compared between the two groups using the SPSS software.Results: The results of 140 welders (mean age: 46.66 ± 13.01 years) and 172 controls (mean age: 45.05 ± 12.61) were analyzed. The values of the Schirmer test and ITBUT were significantly lower in welders than controls; the difference was more prominent for the Schirmer test as compared to TBUT (Schirmer difference = 4.98 mm, ITBUT difference = 2.23 s). OSDI values were also significantly lower in welders than controls (P < 0.001). Considering a cut-off point of 12, 81.2% of welders had degrees of dry eye which was severe in 46.2% while 35.5% of controls had dry eye.Conclusion: The results indicate that the percentage of dry eye and tear problems is far higher in welders than non-welders. Most of the affected welders have severe dry eye. It seems that the main reason for dry eye in these people is aqueous deficiency. [ABSTRACT FROM AUTHOR]

Purpose: To examine the diagnostic validity of different corneal biomechanical parameters for the detection of early keratoconus METHODS: Sixty-one eyes with a diagnosis of early keratoconus and 61 topographically normal eyes were enrolled in the study. All participants underwent testing with the Ocular Response Analyzer (ORA), and 40 indices from each cornea were included in the analysis.Results: The mean (standard deviation: SD) of keratometry and central corneal thickness in keratoconic corneas was 46.9 (2.5) diopter (D) and 473 (31) μm, respectively. Of the 40 evaluated indices, 32 showed a significant difference between the two groups using t-test (p<0.05). According to the results of logistic regression, the indices of height from the lowest to the highest point in peak 2 (H21) and corneal resistance factor (CRF) with R2=0.79 were the best predictors of early keratoconus (p<0.001). H21 ≤190 with a sensitivity and specificity of 87% and 91.8%, respectively, and CRF≤8.6 with sensitivity and specificity of 87% and 85.3%, respectively, yielded an overall diagnostic accuracy of 97.3%.Conclusion: This study results point to the important role of novel waveform-derived indices measured by ORA, along with conventional biomechanical indices, for the early diagnosis of keratoconus. The best predictors of keratoconus in its early stages are H21 and CRF which showed very high sensitivity and specificity for the detection of early keratoconus. [ABSTRACT FROM AUTHOR]

Purpose: The present investigation was done to assess the status of tear film and corneal topography in individuals with long-term exposure to X-ray.Method: This historical cohort study was carried out to compare the lacrimal and corneal findings between radiographers (n = 126) and non-radiographers (n = 172). Radiographers included individuals with at least 5 years of experience in radiography while subjects in the control group had no history of exposure to X-ray. The Ocular Surface Disease Index (OSDI) was filled out by all individuals. Besides, the Pentacam imaging of both eyes was done. Finally, the lacrimal tests including tear break-up time and Schirmer (with anesthesia) were performed for both eyes of the participants.Results: The mean values of the Schirmer and Tear breakup time (TBUT) in the radiographer group (Schirmer: 11.1 ± 3.2 mm, TBUT: 11.3 ± 4.1 s) were significantly lower than the values in control group (14.6 ± 8.1 mm, TBUT: 12.8 ± 4.8 s) (P < 0.0001). The mean OSDI score of the radiographers was significantly higher compared to the control group (24.1 ± 17.6, and 12.3 ± 12.4 respectively (P < 0.0001)). The corneal thickness in the center, inferior, superior, temporal and nasal parts was significantly higher in radiographers versus the control group. In addition, the maximum thickness difference was observed in temporal part (34.00 μm thicker) (P < 0.0001). On the other hand, the corneal eccentricity factor was lower in radiographers compared to the control group (P < 0.0001).Conclusion: Based on the findings of this study, it is concluded that the radiographers have thicker and flatter corneas are than the corneas of the subjects in the control group. However, their corneas had no irregularities. Regarding the tear point, a higher prevalence of dry eye symptoms was observed in the radiographers compared to the control group. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: To determine the prevalence of posterior embryotoxon, corneal opacity, pigment on endothelium, corneal dystrophy, and corneal vascularization in a middle-aged Iranian population, and their association with age and sex.Methods: In a cross-sectional study with multistage cluster sampling, subjects were chosen from 40 to 64-year-old residents of Shahroud in northern Iran. Participants had ophthalmic examinations before and after pupil dilation. Corneal abnormalities were diagnosed by an ophthalmologist using a slit lamp.Results: Of the 6311 invitees, 5190 people (82.2%) participated; 58.6% (n=3040) were female. The prevalence of posterior embryotoxon, corneal opacity, and pigment on endothelium were 14.7% (95% CI: 13.4-16.0), 4.1% (95% CI: 3.4-4.7) and 1.2% (95% CI: 0.9-1.5), respectively, and corneal dystrophy and corneal vascularization were seen in 0.3% (95% CI: 0.2-0.5) and 3.7% (95% CI: 3.0-4.3), respectively. Unlike posterior embryotoxon, the prevalence of all studied abnormalities increased with age after adjusting for sex. The prevalence of posterior embryotoxon (p=0.023) and corneal dystrophy (p=0.038) was significantly higher in women, and the prevalence of corneal opacity (p<0.001) was significantly higher in men. After adjusting for age, sex, and cataract, cases with corneal opacity and corneal vascularization demonstrated significantly worse uncorrected and corrected visual acuity (p<0.001).Conclusion: This report is the first to explore the prevalence of a variety of corneal conditions in a Middle-Eastern population. The findings indicate that one out of five people may have some sort of corneal conditions, and some can impact corrected visual acuity. [ABSTRACT FROM AUTHOR]