مجله چشم پزشکی بینا
سال بیستم شماره 2 (زمستان 1393)

To determine the screening prevalence of amblyopia, refractive errors and strabismus among 7 to 12 year-old primary school children, Tehran, Iran, in 2013. This population based cross sectional study was performed on randomly selected 2410 students from 40 primary schools. Visual acuity was measured using Yang vision tester Snellen E-optotype. If visual acuity was 20/40, the measurements were repeated using a Pinhole. Refractive error was measured by photorefractometer without cycloplegia. Strabismus was checked using cover test and extraocular muscle function tests. Direct ophthalmoscope was used to evaluate the anterior segment, lens opacities, red reflex and fundus. Amblyopia was defined as optimal VA (Pinhole VA) 20/40 in one or both eyes while there were no anatomical problems. Amblyopia was found in 2.3% of participants with no gender difference. It was significantly higher among younger children (p=0.004). The prevalence of hyperopia +2.00D, myopia-0.50D, astigmatism 0.75D and anisometropia (SE difference 1.00D) were 3.5%, 4.9%, 22.7% and 3.9%, respectively. Amblyopia was present in 15.9% of hyperopic and 5.9% of myopic cases. Older age was associated with higher myopia (p<0.001) and lower hyperopia (p<0.029), while astigmatism had no significant difference among the age groups. Strabismus was found in 2.3% of cases. Strabismus, refractive errors especially anisometropia and hyperopia were important risk factors for the development of amblyopia. Compared to developed countries (0.7%), the prevalence of amblyopia (2.3%) was higher in this urvey which highlights the importance of applying on-time and sensitive screening methods. Due to high revalence of amblyopia among children with refractive errors, it is suggested to provide free of charge lasses for free among children younger than 10.

To describe the biometric changes and their effect on intraocular lens (IOL) power calculation after trabeculectomy and to compare the accuracy of four formulas namely SRK/II, SRK/T, Holladay and Hoffer Q for IOL power calculation in these patients. Thirty-four eyes of 31 glaucoma patients who were scheduled for primary trabeculectomy were enrolled. A non-contact biometry device (LenSTAR) was used to measure mean corneal power, axial length, and IOL power, calculated with SRK/T, SRK/II, Holladay and Hoffer Q formulas, in the day before trabeculectomy and 3 and 6 months postoperatively. Postoperative measurements were compared with preoperative values and Bland-Altman plots were used to investigate the agreement between pre and postoperative calculated IOL powers. At postoperative months 3 and 6, axial length decreased by 0.14±0.13 and 0.14±0.15 mm (p<0.001) at, respectively and mean corneal power increased by -0.41±0.46 diopter (p<0.001) and -0.27±0.47 diopters (p=0.008), respectively. Calculated IOL powers were not significantly different from preoperative values (SRK/T formula: -0.01±0.64 (p=0.895) at months 3 and -0.2±0.71 diopters (p=0.17) at months 6, SRK/II formula: - 0.04±0.76 (p=0.738) at months 3 and -0.2±0.74 diopters (p=0.187) at months 6, Holladay formula: 0.1±0.75 (p=0.427) at months 3 and -0.16±0.79 diopters (p=0.319) at months 6, Hoffer Q formula: 0.09±0.76 (p=0.505) at months 3 and -0.14±0.9 diopters (p=0.442) at months 6). After trabeculectomy, the decrease in axial length negated the increase in corneal power which resulted in a non-significant change in postoperative calculated IOL powers as compared to preoperative values.

To evaluate the effects of smoking on the central corneal thickness (CCT). In a historical chohort analytic study, referred cases have been divided into two groups (cigarette smokers, and non–cigarette smokers). Laboratory tests including fasting blood sugar (FBS), blood urea nitrogen (BUN); and blood pressure were checked. Complete eye examination was performed. CCT was measured using the Pentacam. Five hundred and eleven male subjects with a mean age of 35.71±9.58 years were included; 261 (51.1%) subjects were nonsmokers and 250 (48, 9%) were smokers. The smoker group consumed was 14.45±12.82 pack/year. CCT in the whole participants was 536.44±30.29 μm; 537.98±30.29 μm in in the smoking group and534.96±30.11 μm in the in non-smoking group. There was no statistically significant difference in CCT between the study groups. To control confounding effects of age and IOP on CCT, multivariate analyses using linear regression were performed which failed to demonstrate any significant associations between CCT and cigarette smoking (P=0.11). The results of this study exhibit that cigarette smoking has no effect on CCT.

To compare visual acuity, refraction, and complications following deep anterior lamellar keratoplasty (DALK) using cryopreseved donor corneas to outcomes following penetrating keratoplasty (PK) and DALK using fresh donor grafts in keratoconus patients. In this retrospective, comparative, interventional case series, 61 of 61 patients with moderate to advanced keratoconus who underwent corneal transplantation between March 2010 and December 2010 were enrolled. PK was performed conventionally and DALK was performed using the big-bubble techniqueyielding a bared Descemet’s membrane for all cases. DALK used either fresh or cryopreserved corneal tissues as donor grafts. Best corrected visual acuity (BCVA), refractive error, and keratometry readings, as well as postoperative complications were compared between the study groups. Eighteen (29.5%) eyes underwent PK (group 1), 28 (45.9%) eyes received DALK using a fresh corneal graft (group 2), and 15 (24.6%) eyes had DALK using a cryopreserved graft (group 3). Mean follow-up period was 20.2±4.7 months in group 1, 19.4±3.5 months in group 2, and 20.3±5.0 months in group 3 (P=0.65). Finalmean BCVA was 0.14±0.08 logMAR, 0.17±0.11 logMAR, and 0.20±0.09 logMAR, respectively (P=0.22). Final spherical equivalent refraction was -1.49±2.05 D, -3.56±4.38 D, and -2.53±3.02 D, respectively (P=0.16). All study groups were comparable in terms of postoperative complications such as persistent epithelial defects and suture-related complications. The rate of non-endothelial graft rejections was significantly lower in group 3 than in groups 1 and 2 (P=0.03). Cryopreserved corneal tissues can successfully substitute for fresh grafts in DALK performedusing the big-bubble technique to treat keratoconus.

To report the refractive changes after intraocular lens (IOL) implantation in children with congenital and developmental cataract. In this historical cohort study، the clinical records of children between 2 and 15 years old that had lensectomy with posterior capsulotomy، anterior vitrectomy and IOL implantation with more than 5 years of follow-up were studied. Refractive errors were measured at 1 and 3 months postoperatively and every 6 months onwards. Patients were stratified according to age at the time of surgery: group 1 (2-<4 years old)، group 2 (4-<7 years old) and group 3 (7-15 years old). Groups were compared in terms of myopic shift and the rate of changes toward myopia. Additionally، the influence of age at the time of surgery، IOL power and best-corrected visual acuity on myopic shift and the progression rate were assessed. An estimation for undercorrection of IOL power was provided on the basis of the refractive error at the final follow-up examination. Forty-one pseudophakic eyes of 22 children were enrolled. The mean myopic shift was -4. 93 diopters in group 1، -2. 99 diopters in group 2 and -0. 44 diopters in group 3. The rate of refractive change was -0. 53 diopter per year، -0. 39 diopter per year and -0. 12 diopter per year، respectively. Total amount and rate of myopic shift was significantly higher in younger children (less than 7 years old). The variability in refractivechange، measured by standard deviation، decreased from 2. 84 diopter in group 1 to 1. 72 in group 2 to 1. 69 in group 3. In contrast to age، myopic shift had no correlation with IOL power، postoperative refraction and bestcorrected visual acuity. An undercorrection of 20% and 15% in IOL power for 2-4 and 4-7 year-old patients، respectively، would have decreased the odds of high myopic refraction at older ages. Age at the time of surgery had a significant association with myopic shift in pediatric patients who underwent congenital cataract surgery with primary IOL implantation. The rate of myopic shift was also greater in younger children. Although undercorrection of IOL power by 20% and 15% in 2-4 and 4-7 year-old patients، respectively، could decrease the refractive error at the older age، this adjustment might be associated with hyperopia due to variability in the rate of myopic progression.

To investigate the levels of Klotho and Endothelin-1(ET-1) in plasma and aqueous humor in patients with pseudoexfoliation syndrome (PES). Fifteen individuals with PES and 15 age-matched subjects without PES who were scheduled for cataract extraction participated in the study. Samples of aqueous humor and peripheral blood were taken in the operating room just before cataract surgery. All the samples were analyzed using ELISA test to evaluate the levels of Endothelin-1 and Klotho protein. Mean plasma level of Klotho was 56.32 ± 10.25 ng/ml and 65.06 ± 12.32 ng/ml in controls. Mean aqueous level of Klotho was 49.02±10.98 ng/ml and 56.31 ± 7.68 ng/ml, respectively. Mean plasma level of ET- was 1.66 ± 0.75 pg/ml in the PES group and 1.16 ± 0.34 pg/ml in controls. Mean aqueous level of ET-1 was. 28±0.04 pg/ml and 1.17±0.09 pg/ml, respectively. Aqueous (CC = -0.61) and plasma (CC= -0.65) levels of lotho had a negative correlation with the severity of pseudoexfoliation. Neither aqueous nor plasma levels f ET-1 demonstrated such a correlation. Klotho level significantly decreased and ET-1 level significantly increased in pseudoexfoliation yndrome. Klotho exhibited a stronger correlation with the severity of pseudoexfoliation as compared to ET.

To evaluate the effect of a multimedia software program on the ability of interpreting Orbscan II outprints in ophthalmology residents, affiliated to Shahid Beheshti University of Medical Sciences, and compared the results with the conventional teaching method. This prosepective randomized crossover study enrolled 17 ophthalmology residents (11 second year and 6 third year). A multimedia software program was used to teach how to interpret Orbscan II outprints as well as normal and abnormal values of each parameter. Prevoius knowledge was evaluated using a pretest.Therafter, the participants were randomly devided into two groups. In group 1, free discussion was used to deliver materials, while group 2 received the materials through the multimedia software program. After taking posttest 1, two groups were translocated. Posttest 2 was performed 2 weeks after the completion of the study. Nine residents were enrolled in group 1 and 8 in group 2. Mean participant age was 29.1±1.7 years (range, 27 to 32 years) and 29.1±1.7 years (range, 27 to 32 years) in groups 1 and 2, respectively (P=0.81). Maleto- female ratio was 7/2 in group 1 and 6/2 in group 2 (P=0.82). Second-year residents constituted 66.7% of participants in group 1 and 62.5% of participants in group 2 (P=0.91). The results of pretest were comparable between the study groups. A significant increased in posttest 1 score was obsereved in group 1. However, the software program could not result in a significant increase in the pretest 1 score in group 2. Posttest 2 score was signifcantly higher in both study groups as compared to pretest score. Only the traditional method could increase the ablity of interpreting Orbscan II out prints in ophthalmology residents, affiliated to Shahid Beheshti University of Medical Sciences, while the multimedia software failed to significantly increase this ability.

To study the knowledge and performance related to computer vision syndrome among computer users at Guilan university of Medical sciences. This cross - sectional study was conducted on 280 computer users. The sample was selected using a stratified random sampling. Data were collected through a questionnaire adopted from the relevant literature. The questionnaire consisted of three sections: demographic, knowledge and performance. For the knowledge section, the score for correct answer was 1 and the score for the items of "incorrect", “I don’tknow” and "no answer" was 0. Accordingly, the Knowledge status was graded weak, medium, good and excellent. Performance status was graded as favorable or unfavorable. Data were coded and analyzed by ttest, ANOVA, and chi-square test using the SPSS software (16 version). The mean participant age was 38.1±8.05 years. The majority of participants were female (66.8%) and had bachelor's degree (54.3%). The mean time of daily working on computer was 4.6 ±2.17 hours with a history of working on computer for 8.74.9 years, on average. Only 3.3% of the users passed an educational course on ergonomic principles of computer. The average score of awareness (knowledge) in users was 41.39±19.38. Additionally, the rate of user’s knowledge about different domains of computer varied from 5.4% to 90%. The level of knowledge was not significantly associated with age and history of computer-working, while it showed a significant association with the level of education (p<0.03). The performance was undesirable in 95%, 87.1%, 68.7% and 62.7% of cases with respect to setting the refreshment rate, setting the eye distance from the top edge of the monitor, setting the contrast and illumination, and receiving regular eye examinations. In this study, the level of user's knowledge related to computer vision syndrome was medium their performance was unacceptable.

Deep anterior lamellar keratoplasty (DALK) has recently been introduced as an alternative procedure to penetrating keratoplasty (PK) for corneal pathologies not affecting the corneal endothelium. DALK does not rely on donor endothelium and requires less rigid criteria for donor corneal tissue quality. Therefore, DALK makes it possible to use donor corneas deemed unsuitable for PK. Furthermore, lamellar keratoplasty allows acellular corneal tissue to be transplanted. As a result, long-term preservation techniques are being revisited to increase the availability of donor corneas and subsequently alleviate constraints of availability, cost, storage, and transportation in many countries. The recent alterations in corneal transplantation techniques and hence the type of donor cornea tissues used for each technique, may require corneal surgeons and eye banks to reevaluate their selection criteria. The purpose of this systematic review is to present an updated analysis on the type and quality of donor corneas used for PK and DALK, assess the influence of donor and eye bank factors on the quality of donor corneas, and determine whether any of these donor factors affect clinical outcomes, complications, and graft survivals.

Blow out fracture is a common disease in oculoplastics clinics. One of indication for surgical intervention is entrapment of inferior rectus muscle in the fractured site. In this article authors represent two cases with this disease who underwent surgery for the entrapment of perimuscular fascia without inferior rectus muscle involvement. The results of treatment in both cases were excellent. The study was aimed to represent the specific clinical and radiological findings.