The prevalence of myopia in schoolchildren in Northeastern Iran is considerably lower than that of East Asian populations, but similar to many other populations, including South Africa, Chile and other countries of the Middle East. Whilst comparisons with other studies show that the prevalence of hyperopia and astigmatism in Northeastern Iran is higher than that of some countries, it is lower compared with others.

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To compare the corneal cone location on different maps and instruments and their agreements with elevation maps. Methods:In 90 left eyes with bilateral keratoconus, the apex of cone location was determined based on the maximum simulated keratometry (Kmax) location on the anterior sagittal curvature map by Pentacam HR, the maximum curvature on the mean curvature map by ATLAS 9000, most elevated point of the island of positive elevation relative to the best fit sphere on the front and back corneal elevation maps by Pentacam HR, and thinnest point on the thickness map by Pentacam HR and Orbscan, and the thinnest points on pachymetry and epithelial thickness maps by RTVue OCT.Results: There was a significant difference among the location on different maps along the xand y-axes (p< 0.001). The lowest agreement with the cone apex on both front and back elevation maps was for the anterior sagittal curvature map and the highest agreement for the Pentacam thickness map. The majority of keratoconus cone apexes were displaced in the inferotemporal direction on the different maps except for the epithelial thickness maps.Conclusions: Despite the variability between different devices and methods; the thickness map on the Pentacam HR showed the highest correlation with the front and back elevation maps, while the RTVue epithelial thickness map showed the poorest correlation. Based on this study, epithelial thickness maps and anterior curvature maps should be utilized with caution to determine the location of the cone.

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Objective The Müller-Lyer illusion is a visual illusion in which a horizontal shaft with an inward-pointing chevron (fins-out) affixed to each end is perceived longer than a shaft with outward-pointing chevrons (fins-in). The goal of this study was to compare the effects of experience and knowledge about the Müller-Lyer illusion on participants' perceptual precision. Method Participants were undergraduate students (n = 108) who were not familiar with the Müller-Lyer illusion prior to the experiment. The task of participants was to adjust one movable line to make it equal to the other in Müller-Lyer figure. They received ascending and descending Müller-Lyer trials in three blocks with 20 trials each. The Experimental Group received information about the Müller-Lyer illusion prior to the third block. Results For the Experimental Group, the amount of departure in Block 3 was reduced significantly compared with previous blocks. Conclusion Knowledge about the mechanisms underlying visual illusions may play an important role in helping individuals overcome them.

Purpose: To assess the therapeutic efficacy of a combinational therapy, including conventional treatment and intense pulsed light (IPL) technique on sleep quality of patients with meibomian gland dysfunction (MGD). Methods: Fifty participants with a clinical diagnosis of MGD were enrolled in this study. Participants underwent three sessions of IPL therapy. There was a 2-week interval between IPL sessions 1 and 2 and 1 month between sessions 2 and 3. Treatment was supplemented with conventional home-based therapy (including lid hygiene, warm compress, eyelid massage, and lid margin scrub) for MGD. Dry eye symptomatology, tear film, and ocular surface parameters were evaluated at baseline (day 0) and days 15, 45, and 75. Sleep quality was assessed before and after the study using Pittsburgh Sleep Quality Index (PSQI). Results: PSQI components improved significantly at day 75 in comparison with the baseline (all P < 0.05). Ocular Surface Disease Index (OSDI) score, noninvasive Keratograph tear break-up time (NIKBUT), fluorescein tear break-up time (FTBUT), meibomian gland expressibility, meibum quality score, and tear osmolarity improved at follow-up visits ( P < 0.05). Younger patients showed more improvement in NIKBUT, sleep quality, and duration ( P = 0.024, P = 0.047, and P = 0.008). Sleep latency decreased with increased NIKBUT and FTBUT and decreased OSDI score ( P = 0.001, P = 0.005, and P = 0.041). Conclusions: The treatment of MGD is effective for improving sleep quality. Younger patients may preferentially benefit from the treatment.

Purpose:To evaluate the enhancing effects of vision therapy on eye–hand coordination skills in students with visual impairments.Methods:Thirty-five visually impaired patients who underwent vision therapy comprised the treatment group, and 35 patients with impaired vision who received no treatment comprised the control group. Full ophthalmic examinations were performed, including biomicroscopy, retinoscopy, and assessments of subjective refraction and visual acuity. Eye–hand coordination was evaluated using the Frostig test. Vision therapy in the treatment group was performed using the Bernell–Marsden ball, perceptual-motor pen, random blink test, and random shape assessment.Results:Data were analyzed for the 35 visually impaired patients and 35 control participants. The mean age was 11.51 ± 3.5 and 11.09 ± 3.1 years in the treatment and control groups, respectively. Female participants comprised 80% of the treatment group and 57% of the control group. Before treatment, the mean scores on the Frostig test were 22.74 ± 4.32 and 21.60 ± 4.10 in the treatment and control groups, respectively, and after treatment, the mean Frostig test scores were 24.69 ± 3.99 and 21.89 ± 3.92, respectively. Statistically significant intergroup differences were found in eye–hand coordination (P < 0.05). No significant intergroup differences were noted in the distance and near visual acuity values.Conclusion:The results demonstrated that vision therapy could significantly improve eye–hand coordination, but no enhancement was found in near or distance visual acuity.

Purpose:To compare three different methods for determining addition in presbyopes.Methods:The study included 81 subjects with presbyopia who aged 40-70 years. Reading addition values were measured using 3 approaches including the amplitude of accommodation (AA), dynamic retinoscopy (DR), and increasing plus lens (IPL).Results:IPL overestimated reading addition relative to other methods. Mean near addition obtained by AA, DR and IPL were 1.31, 1.68 and 1.77, respectively. Our results showed that IPL method could provide 20/20 vision at near in the majority of presbyopic subjects (63.4%).Conclusion:The results were approximately the same for 3 methods and provided comparable final addition; however, mean near additions were higher with increasing plus lens compared with the other two methods. In presbyopic individuals, increasing plus lens is recommended as the least time-consuming method with the range of ±0.50 diopter at the 40 cm working distance.