Asieh Ehsaei

White-to-white corneal diameter: normal values in healthy Iranian population obtained with the Orbscan II.

AIM To determine the normative values of white-to-white corneal diameter with Orbscan II Topography System and to compare right and left eyes data in the normal young population. METHODS A total of 1001 healthy participants aged 18-45y participated in this observational cross-sectional study. The study population consisted of 616 female and 385 male subjects. The corneal diameter was measured with the Orbscan II. The differences between genders, between right and left eyes and age-related changes were evaluated. Statistical analyses were performed using Students t-test. RESULTS The average white-to-white distance in our study population was recorded as 11.65±0.36 mm (median: 11.60 mm, mode: 11.70 mm, minimum: 10.50 mm and maximum: 13.60 mm). The white-to-white distance was 11.60±0.35 mm in males and 11.71±0.36 mm in females which was statistically different between genders (P<0.01). However, white-to-white distance was not statistically different between right and left eyes. In addition, this parameter decreased with increasing age. Considering 95% confidence interval, corneal diameter less than 10.93 mm and greater than 12.34 mm would be considered as microcornea and megalocornea, respectively based on this study population, using the Orbscan II topography. CONCLUSION Detailed description and analysis of corneal diameter with Orbscan demonstrate that the obtained average value of horizontal white-to-white is higher in male than female and decreases slightly with increasing age. Our data also suggests the cut off values for definition of microcornea and megalocornea, which can be employed with this population.

Part-time versus full-time occlusion therapy for treatment of amblyopia: A meta-analysis

Purpose To compare full-time occlusion (FTO) and part-time occlusion (PTO) therapy in the treatment of amblyopia, with the secondary aim of evaluating the minimum number of hours of part-time patching required for maximal effect from occlusion. Methods A literature search was performed in PubMed, Scopus, Science Direct, Ovid, Web of Science and Cochrane library. Methodological quality of the literature was evaluated according to the Oxford Center for Evidence Based Medicine and modified Newcastle-Ottawa scale. Statistical analyses were performed using Comprehensive Meta-Analysis (version 2, Biostat Inc., USA). Results The present meta-analysis included six studies [three randomized controlled trials (RCTs) and three non-RCTs]. Pooled standardized difference in the mean changes in the visual acuity was 0.337 [lower and upper limits: −0.009, 0.683] higher in the FTO as compared to the PTO group; however, this difference was not statistically significant (P = 0.056, Cochrane Q value = 20.4 (P = 0.001), I2 = 75.49%). Eggers regression intercept was 5.46 (P = 0.04). The pooled standardized difference in means of visual acuity changes was 1.097 [lower and upper limits: 0.68, 1.513] higher in the FTO arm (P < 0.001), and 0.7 [lower and upper limits: 0.315, 1.085] higher in the PTO arm (P < 0.001) compared to PTO less than two hours. Conclusions This meta-analysis shows no statistically significant difference between PTO and FTO in treatment of amblyopia. However, our results suggest that the minimum effective PTO duration, to observe maximal improvement in visual acuity is six hours per day.

Distribution of normal superficial ocular vessels in digital images

PURPOSE To investigate the distribution of different-sized vessels in the digital images of the ocular surface, an endeavor which may provide useful information for future studies. METHODS This study included 295 healthy individuals. From each participant, four digital photographs of the superior and inferior conjunctivae of both eyes, with a fixed succession of photography (right upper, right lower, left upper, left lower), were taken with a slit lamp mounted camera. Photographs were then analyzed by a previously described algorithm for vessel detection in the digital images. The area (of the image) occupied by vessels (AOV) of different sizes was measured. Height, weight, fasting blood sugar (FBS) and hemoglobin levels were also measured and the relationship between these parameters and the AOV was investigated. RESULTS These findings indicated a statistically significant difference in the distribution of the AOV among the four conjunctival areas. No significant correlations were noted between the AOV of each conjunctival area and the different demographic and biometric factors. Medium-sized vessels were the most abundant vessels in the photographs of the four investigated conjunctival areas. The AOV of the different sizes of vessels follows a normal distribution curve in the four areas of the conjunctiva. The distribution of the vessels in successive photographs changes in a specific manner, with the mean AOV becoming larger as the photos were taken from the right upper to the left lower area. CONCLUSIONS The AOV of vessel sizes has a normal distribution curve and medium-sized vessels occupy the largest area of the photograph.

Effect of topical diclofenac on postoperative photorefractive keratectomy pain: a randomized, controlled trial

A major disadvantage of photorefractive keratectomy is postoperative pain and discomfort. This study aims to evaluate whether topical diclofenac 0.1% therapy adds any extra benefit to systemic diclofenac in controlling pain after photorefractive keratectomy.

Distribution of different sized ocular surface vessels in diabetics and normal individuals

Purpose: To compare the distribution of different sized vessels using digital photographs of the ocular surface of diabetic and normal individuals. Methods: In this cross-sectional study, red-free conjunctival photographs of diabetic and normal individuals, aged 30-60 years, were taken under defined conditions and analyzed using a Radon transform-based algorithm for vascular segmentation. The image areas occupied by vessels (AOV) of different diameters were calculated. The main outcome measure was the distribution curve of mean AOV of different sized vessels. Secondary outcome measures included total AOV and standard deviation (SD) of AOV of different sized vessels. Results: Two hundred and sixty-eight diabetic patients and 297 normal (control) individuals were included, differing in age (45.50 ± 5.19 vs. 40.38 ± 6.19 years, P < 0.001), systolic (126.37 ± 20.25 vs. 119.21 ± 15.81 mmHg, P < 0.001) and diastolic (78.14 ± 14.21 vs. 67.54 ± 11.46 mmHg, P < 0.001) blood pressures. The distribution curves of mean AOV differed between patients and controls (smaller AOV for larger vessels in patients; P < 0.001) as well as between patients without retinopathy and those with non-proliferative diabetic retinopathy (NPDR); with larger AOV for smaller vessels in NPDR (P < 0.001). Controlling for the effect of confounders, patients had a smaller total AOV, larger total SD of AOV, and a more skewed distribution curve of vessels compared to controls. Conclusion: Presence of diabetes mellitus is associated with contraction of larger vessels in the conjunctiva. Smaller vessels dilate with diabetic retinopathy. These findings may be useful in the photographic screening of diabetes mellitus and retinopathy.

Visual field assessment in high myopia with and without tilted optic disc

The aim was to evaluate the effect of the tilted optic disc on the visual field in highly myopic eyes.

Structure versus function in high myopia using optical coherence tomography and automated perimetry

To examine the structure–function relationship between retinal thickness using spectral‐domain optical coherence tomography and standard automated perimetry in high myopia.

Comparison of cyclopentolate versus tropicamide cycloplegia: A systematic review and meta-analysis

Purpose The aim of the present meta-analysis is to compare the efficacy of cyclopentolate and tropicamide in controlling accommodation during refraction. Methods A comprehensive literature search was performed in PubMed, Scopus, Science direct and Ovid databases by the key words: “tropicamide”; “cyclopentolate”; “cycloplegia” and “cycloplegic” from inception to April 2016. Methodological quality of the literature was evaluated according to the Oxford Center for Evidence Based Medicine and modified Newcastle-Ottawa scale. Statistical analyses were performed using Comprehensive Meta-Analysis (version 2; Biostat Inc., USA). Results The present meta-analysis included six studies (three randomized controlled trials and three case–control studies). Pooled standardized difference in the mean changes in the refractive error was 0.175 D [lower and upper limits: −0.089; 0.438] more plus in the cyclopentolate group compared to the tropicamide group; however, this difference was not statistically significant (p = 0.194; Cochrane Q value = 171.72 (p < 0.05); I2 = 95.34%). Eggers regression intercept was −5.33 (p = 0.170). Considering type of refractive errors; refractive assessment procedure and age group; although cycloplegic effect of cyclopentolate was stronger than tropicamide; however, this effect was only statistically significant in children; hyperopic patients and with retinoscopy. Conclusion We suggest that tropicamide may be considered as a viable substitute for cyclopentolate due to its rapid onset of action. Although these results should be used cautiously in infants and in patients with high hyperopia or strabismus when using tropicamide as the sole cycloplegic agent especially in situations that the findings are variable or there is no consistency between the examination results and clinical manifestations of the visual problems.