مجله چشم پزشکی بینا
سال شانزدهم شماره 1 (پاییز 1389)

Iran enjoys a glorious history in medicine, ophthalmology and optics and has introduced several great physicians and ophthalmologists to the world. The history of ophthalmology dates back to 6000 years ago; unfortunately we have no manuscripts or petrographies from those eras. The oldest document about ophthalmic diseases can be found in Avesta. Furthermore, as early as 1600 years ago, Genta Shapirta or Gundishapur revolutionized all sciences including ophthalmology. In this paper, the history of remarkable Iranian physicians in the field of ophthalmology is reviewed. In addition, new ophthalmic departments are briefly introduced.

To determine the incidence and prevalence of clinical keratoconus (KCN) in Yazd province.

In this population-based survey, a surveillance program was established in Yazd province (population size=990,818). All new clinically diagnosed cases of KCN were registered and referred for topographic imaging during one year (2008-2009) by all local ophthalmologist and optometrists. People living less than 6 months in the province and those with known KCN before the beginning of the study were excluded. Diagnosis was based on topographic pattern (TMS-4a, Tomey, Japan) and indices including KPI, KCI and KSI and re-examination by an anterior segment subspecialist. Finally, referred patients were classified into 5 groups including, clinical KCN, early KCN, KCN suspect PMD (pellucid marginal degeneration) and non KCN corneal diseases. Incidence rate was calculated as the number of new cases divided by the province population and the prevalence was based on the Iranian life-expectancy (73 years).

During the study period, 685 patients were referred. Of these, 149 were excluded and 28 patients did not attend for topographic imaging (95% response rate). Topographic images showed suspect or definite patterns for KCN in 47.76% of participants (256/536 subjects). After re-examination the number of subjects with clinical and early KCN, PMD and suspect KCN was 108, 72, 9 and 20, respectively; 8 patients had other corneal disorders. Among 39 patients, not participating in the re-examination, based on topographic images 32, 6 and one person were classified as KCN, suspect and non-KCN groups, respectively. Consequently, the annual incidence rates of KCN in Yazd province were calculated as 22.3 (excluding suspects) and 24.9 (including suspects) in 100,000 and the prevalence was 1.4% and 1.55% excluding and including suspects, respectively.

The incidence of KCN in Yazd province is noticeable and consistant with other studies on Asian ethnic groups. This is much higher than the incidence in European Caucasians and warrants further genetic and environmental studies

To evaluate the effect of posterior residual stroma on visual function after unsuccessful Anwar's deep anterior lamellar keratoplasty (DALK). Methoods: In this parallel historical cohort, visual acuity and refractive status were evaluated after Descemetic DALK (group 1) and compared with those of pre-Descemetic DALK (group 2). One hundred and ten keratoconic eyes were enrolled. A bare Descemet’s membrane (DM) was successfully achieved in 93 (84.5%) eyes in group (1) and 17 (15.4%) eyes in group (2). Mean follow-up period was 208 and 207 months in groups (1) and (2), respectively (P= 0.08). Postoperative best spectacle-corrected visual acuity (BSCVA) was significantly better in group (1) than in group (2) at 1, 3, 6 and 12 months. However, there was no significant difference between study groups at final examination. The two groups were comparable in terms of keratometric astigmatism and spherical equivalent refractive error throughout the follow-up period. Retention of posterior corneal stroma delays visual recovery after DALK using Anwar's technique; however, both descemetic and pre-descemetic methods have acceptable and comparable visual acuity levels at final follow-up.

To determine peripapillary retinal nerve fiber layer (RNFL) thickness by three-dimensional optical coherence tomography (3D-OCT) in a normal Iranian population and to evaluate the concordance of these measurements with those obtained by the second generation of optical coherence tomography (OCT II). In a cross-sectional observational study, 96 normal Iranian subjects 20-53 years of age were enrolled. Peripapillary RNFL thickness in one randomly selected eye of each subject was measured by 3D-OCT and also by OCT II. Standard achromatic perimetry, corneal pachymetry and A-scan ultrasonographic biometry were also performed. Other study variables included age, gender, laterality (right versus left eye), refractive error, corneal diameter and disc area. Mean peripapillary RNFL thickness measured by 3D-OCT (75.50±8.38 µm) was significantly less than that measured by OCT II (144.10±33.32 µm) (P<0.001). Using 3D-OCT, no significant difference in peripapillary RNFL thickness was observed by gender (P=0.90) or laterality (P=0.17); RNFL thickness had no correlation with age (P=0.95), axial length (P=0.32), spherical equivalent refractive error (P=0.21), central corneal thickness (P=0.66) and disc area (P=0.31). However, a positive correlation was found between peripapillary RNFL thickness and corneal diameter (P=0.03). 3D-OCT seems to yield lower RNFL thickness values as compared to OCT II. It seems advisable to obtain separate baseline measurements when using different generations of OCT machines.

To evaluate the distribution of TNF-alpha promoter -1031T/C and -308G/A polymorphisms in an Iranian population with Behcet disease and ocular manifestation. We investigated the distribution of TNF-alpha promoter -1031T/C and -308G/A polymorphisms in 53 patients with Behcet disease (BD) and 79 matched healthy controls, using the PCR-RFLP technique. All subjects were from an Iranian Azeri population. The frequency of the TNF-alpha -308G/A polymorphism was similar in BD patients and healthy controls (P= 0.234) whereas the frequency of the TNF-alpha-1031T/C polymorphism was different between two groups (P= 0.0006). The frequency of the CG haplotype was significantly higher (P< 0.0001), and that of the TA haplotype was significantly lower in BD patients than healthy controls. Different TNF--1031T/C and TNF--308G/A polymorphisms were not associated with ocular involvement. TNF-alpha is a susceptibility gene for BD in Iranian patients of Azeri ethnicity. There was no relation between different haplotypes in the investigated genetic region in this group of BD patients with ocular manifestation.

Controversy has recently risen about the presence of compensatory ocular countertorsion (COCT) after head tilt. This study was performed to define the functional range of this phenomenon. Cycloplegic autorefraction was performed on 80 eyes with regular astigmatism 2D. Objective autorefraction was performed in normal position, right and left head tilt positions of 5º, 10º, 15º, 20º, and 25º. Any change in astigmatic axis after head tilt was considered as COCT defect. The authors designed a tiltometer which was fixed over the patient's head without disturbing proper refractometry in various head positions. Enrolled eyes had no other ocular disease except refractive error. Seventy eyes completed the study process. Mean age of the patients was 26.5±10 (15-48) years. Mean amplitude of COCT was 1.87°±1.81 (0°-5°) at 5° and 6.91°±4.96 (0º-20°) at 25° head tilt angles. COCT values with left head tilt were significantly lower than COCT values with right head tilt (P<0.026). Incyclotorsional compensation in each eye was not necessarily equal to the excyclotorsional compensation of the fellow eye, but this torsional discrepancy was not overal significant (P>0.237). COCT was found to be an unreliable phenomenon. Any minimal head tilt can induce erroneous measurement of astigmatic axis during refractometry.

To compare the results of conventional hang-back technique (CHBT) with that of anchored hang-back technique (AHBT) for bilateral lateral rectus (LR) recession in patients with exotropia. In this randomized clinical trial, 60 patients underwent CHBT (group 1) or AHBT (group 2) for LR recession (30 patients in each group). Preoperative and postoperative deviation, age, sex, the amount of recession and complications were compared between the two groups during follow up. Mean age was 14.2±10.3 (3-42) and 11.5±9.3 (3-42) years in groups 1 and 2, respectively. Mean preoperative distance and near deviation in group one were 35±7.0 PD and 34.6±6.8 PD; corresponding figures in group two were 34.6±7.1 PD and 33.3±7.7 PD, respectively. Mean postoperative deviation at near and distance were 8 ± 9.4 PD and 7.2±9.1 PD in group one and 8.7±7.8 PD and 8.1±7.5 PD in group two, respectively (P=0.48 and 0.98 for distance and near). At final examination, 63.3% of subjects in group one and 60% of cases in group two were within 10 PD of orthophoria. Serious complications including globe perforation, A and V patterns and vertical deviations were not observed. There was no statistically significant difference between the two groups in terms of success rate (P=0.79) and complications. The success rate of both CHBT and AHBT for lateral rectus recession are comparable and favorable in patients with exotropia.

To investigate the relationship between higher-order aberrations (HOAs) and contrast sensitivity function (CSF) in myopes. In this cross-sectional study, HOAs and CSF were measured in myopic eyes over a 6-mm pupil. Pupil diameter was measured in photopic condition. The correlation between HOAs and CSF was investigated using multivariate linear regression analysis. Seventy right myopic eyes of 70 subjects with a mean age of 26.6±5.7 years were studied. Mean spherical equivalent (SE) and refractive astigmatism were -4.97±1.6 D and 0.93±0.5 D, respectively. AULCSF was significantly but indirectly correlated with cycloplegic SE (R2=0.57, P=0.02), the root mean square (RMS) of total HOA (R2=0.065, P=0.03), 4th-order aberration (R2=0.089, P=0.015) and spherical aberration (R2=0.037, P=0.004). AULCSF had no significant association with age, photopic pupil diameter, refractive astigmatism, and RMS of coma aberration. Spherical and 4th-order aberrations significantly affect contrast sensitivity function. However, other factors such as neural elements of visual pathway may have a role.

To compare the visual outcomes and complications of phacoemulsification surgery in patients with and without vitreous loss (VL). A historical cohort study was performed on patients attending Labbafinejad Hospital who had underwent phacoemulsification surgery and was complicated by VL from April 2006 to March 2007. A control group was selected randomly from patients with uncomplicated phacoemulsification surgery during the same period. Best corrected visual acuity (BCVA) and posterior segment complications of phacoemulsification surgery were compared between these two groups using SPSS 15. The VL group included 70 cases; among them, BCVA was 20/40 or better in 39 (56%) cases. Seventy nine patients entered the control group; of whom, BCVA was 20/40 or better in 62 (78%) cases (P<0.001). In the VL group, 4 patients developed cystoid macular edema (CME) and 6 patients developed clinically significant macular edema (CSME) while in the control group only 2 patients developed CME (P<0.05). Furthermore, 4 patients developed rhegmatogenous retinal detachment (RRD) in the VL group while there were no cases of RRD in the control group (P<0.05). Vitreous loss during phacoemulsification surgery reduced postoperative BCVA significantly. The rate of postoperative CME and RRD was also significantly higher with this condition.

Orbital lynphangioma is a low-flow or no-flow vascular malformation. It is a congenital and isolated hemodynamic lesion in which the clinical presentation and onset are related to orbital, peri-orbital or intracranial involvement. In addition, history of previous trauma and upper respiratory tract infection are important predictor factors. High resolution MRI, Doppler ultrasound and CT-scan are useful for diagnosis. Observation is the preferred method of management except for lesions with visual loss and cosmetic problems. Treatment methods depend on individual clinical and paraclinical manifestations of each patient.

To report a case of lymphangioma in the lacrimal gland.Case Report: A 6-year old boy with acute proptosis and inferonasal displacement of the globe was referred. In CT-Scan revealed a heterogenous enlargement of the lacrimal gland. Steroid therapy did not lead to a significant improvement. During surgical exploration, a dark black liquid was extracted from the site of the lacrimal gland and pathology confirmed lymphangioma of the lacrimal gland. Clinical signs and symptoms improved after surgery and no recurrence has occurred up to one year. Lymphangioma must be considered as a differential diagnosis in acute enlargement of the lacrimal gland especially in a child or young patient