مجله چشم پزشکی بینا
سال پانزدهم شماره 2 (زمستان 1388)

To determine the incidence, concurrent factors and clinical results of re-operation after corneal refractive surgeries. In this retrospective descriptive study records of all patients undergoing corneal refractive surgeries including PRK, LASIK, and LASEK between April 2005 and December 2006 were assessed. Patients who had undergone re-operations entered the study; visual acuity with and without correction, and refraction before and after the operation were analyzed. Out of 10,311 eyes of 5,257 patients, 63 eyes (0.6%) underwent one or more re-operations. The mean duration between the first and second operation was 11620 days. Mean±SD spherical equivalent refractive error before the first operation in re-operated eyes was -4.40±3.17 D (ranging from -14.25 to +5.88 D), -4.58±3.25 D (ranging from -14.25 to +5.18 D) in the LASIK group, and -2.73 to±1.61 D (ranging from -5.13 to 0.8 D) in the PRK group. Mean±SD of spherical equivalent refractive error of these patients before re-operation was -1.13±1.97 D (ranging from -4.25 to +3 D). This mean value was -1.25±1.71 D (ranging from -4.25 to +3.00 D) and -0.45±1.7 D (ranging from -2.75 to +1.5 D) in the LASIK and PRK groups respectively. Before re-operation, only 30% of re-operation candidates had visual acuity of 20/40 or better while all of them reached this level of visual acuity after re-operation. Laser corneal refractive re-operation can be a safe and efficient alternative for treatment of residual refractive errors after previous photorefractive surgery and the low prevalence and incidence of re-operation among Iranian patients can be a sign of suitable nomograms used in patients of Iranian descent.

To evaluate the visual outcomes of cross-cylinder ablation in Laser in Situ Keratomileusis (LASIK) for eyes with high astigmatic refractive errors and low spherical component. We prospectively evaluated cross cylinder LASIK in patients with high astigmatic refractive error but low spherical component over a period of 2 years. All procedures were performed with the Nidek EC-5000 excimer laser. Main outcome measures included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and complications. Thirty-four eyes of 22 patients were included. Patients were followed for 21.8± 3.6 months. At the last examination, UCVA of 20/40 or better was observed in 33 eyes (97.1%). BSCVA after LASIK improved significantly in comparison to BSCVA before surgery (p<0.005). The mean preoperative cylinder was-4.73±0.89D (-4.00 to -7.00 D) which was reduced to -0.29±0.47 D (0.00 to -1.50 D) at the last follow up visit (P<0.001). No cases of postoperative astigmatic regression or corneal haze were observed. Cross cylinder LASIK with the Nidek EC-5000 is a successful procedure for correction of high astigmatism. It seems to be clinically safe, effective and predictable.

To analyze the results of scanning slit topography (Orbscan II, Bausch & Lomb) in both eyes of patients with unilateral Fuchs’ heterochromic iridocyclitis An intra-subject non-interventional case-control study was conducted on patients with unilateral Fuchs’ heterochromic iridocyclitis (FHI). None of the patients had history of ocular surgery. Corneal topographic parameters obtained with Orbscan II including simulated keratometry (Sim K) values, anterior and posterior surface maximum elevations and central corneal thickness were compared between the two eyes and analyzed statistically. Thirty patients were enrolled in this study. Mean age was 33.310.6 years (range: 18 to 58 years). Mean Sim K astigmatism was 1.651.27 diopters in FHI eyes and 0.880.52 diopters in fellow eyes (P=0.001). Mean axis of astigmatism was 88.7532 degrees in FHI eyes. Mean anterior surface maximum elevation values in FHI and fellow eyes were 11.70±7.00 and 10.60±4.9 µm, respectively (P=0.37). Mean posterior surface maximum elevation values in FHI and fellow eyes were 27±12.1 µm and 23±8.1 µm, respectively (P=0.128). Corneal astigmatism is a common finding in eyes with FHI, and disparity of corneal astigmatism between the two eyes can be added to the diagnostic criteria for the unilateral form of this disease. This finding must be considered during cataract surgery in these patients.

To compare the efficacy and safety of Xalatan(R) with generic Latanoprost (Xalabiost) in glaucoma. In this randomized crossover study, 17 patients with primary open angle glaucoma or ocular hypertension were randomized into 2 groups. Group A received Xalatan for 6 weeks followed by Xalabiost for 10 weeks. Group B received Xalabiost for 6 weeks which was then crossed over to Xalatan for 10 weeks. At the baseline visit and the end of weeks 6 and 16, intraocular pressure (IOP) was measured at 9, 12 and 15 o’clock and the patients were asked and examined for adverse effects of the drugs. IOP at baseline was 20.83±3.34 mmHg in group A and 23.33±6.71 mmHg in group B (P=0.155). After 6 weeks IOP (% reduction) was 15.57±3.81 mmHg (24.05%) in group A and 17.62±3.43 mmHg (18.83%) in group B (P=0.373). At the end of week 16, mean IOP was 14.26±2.68 mmHg (28.60%) in group A and 16.90±2.74 mmHg (21.11%) in group B (P=0.167). The most common adverse effects with both drugs were hyperemia and itching; although more frequent while receiving Xalatan, the difference was not significant. In our study, Both Xalatan and Xalabiost decreased IOP significantly and similarly, and the incidence of adverse effects was not significantly different between the two drugs.

To determine the dissection level during deep lamellar keratoplasty (DALK) using the big-bubble technique by light microscopy (LM) and transmission electron microscopy (TEM). Descemet’s membrane (DM) and stromal tissue of 4 keratoconic eyes were removed because of inadvertent intraoperative DM perforation during DALK which was converted to penetrating keratoplasty. These specimens were divided in two halves, one half was fixed in 10% formalin for LM, and the other half was fixed in 2.5% glutaraldehyde for TEM. LM examination of the corneal stromal and DM specimens, disclosed scattered round empty spaces consistent with air bubbles within the stroma, and PAS-positive membrane with adherent endothelia on one side and scant amounts of posterior stroma including keratocytes on the other side. Separation of stromal corneal tissue from DM during DALK using the big-bubble technique for keratoconic eyes occurs within the deep stromal tissue near DM.

To evaluate the adverse effects of intravitreal injection of sterile chloramphenicol eye drops on corneal endothelial cells of donated corneas. 100 donor corneas were enrolled in the study. One eye of each donor underwent intravitreal injection of sterile chloramphenicol eye drops following vitreous tap and the fellow eyes were served as controls. After corneo-scleral excision, the corneal endothelium was examined with slitlamp biomicroscopy and confocal microscopy; results were compared with control eyes using paired t-test and Wilcoxon signed ranks test. No significant difference was noted in Descemet’s foldings (P= 0.785), endothelial cell density (P= 0.908), coefficient of variation (P= 0.801), and percentage of hexagonal cells (P= 0.370) between injected eyes and the control group. Intravitreal injection of sterile chloramphenicol eye drops in donated globes following diagnostic vitreous tap is not associated with adverse effects on the corneal endothelium.

To evaluate the knowledge and practice of computer users about computer related eye problems. One hundred twenty-three computer users were asked to complete a questionnaire. In each questionnaire, after initial demographic questions, 9 questions were conducted to evaluate the knowledge of the users and 9 questions to assess their attitude about the computer vision syndrome (CVS). Sixty-nine women and 54 men with mean age of 31.3±7.1 years were studied. All of the users had daily computer work of more than 1 hour and 70 users (56.2%) had more than 3 hours of daily computer work. The correct responses ranged from 7.6% to 78.5% for knowledge questions, and from 25.3% to 76% for practice questions. In 1 knowledge question (proper contrast and brightness) and 2 practice questions (contrast and brightness adjustment and maximum working time without rest), more than 50% of the users responded correctly. The lowest correct responses were the optimum room light (7.6%) in the knowledge section and ocular examinations (25.3%) in the practice section. Twenty-eight users (22.8%) said they had read about the CVS in scientific sources, however, only 2 (7.1%) knew all signs and symptoms of CVS. No user correctly responded to all questions about the appropriate approach to CVS. The level of knowledge of the studied population about the CVS was limited. Proper use of the present knowledge was low as well.

To investigate the efficacy of topical cyclosporine A 2% in treating and preventing recurrent graft rejection episodes after penetrating keratoplasty (PKP) in patients with history of previous rejection episodes. In this clinical trial, eligible PKP patients were randomly given topical cyclosporine A 2% or placebo in addition to a standard corticosteroid regimen for an episode of recurrent subepithelial or endothelial graft rejection. Primary indications for transplantation were keratoconus, Fuchs’ endothelial dystrophy, corneal stromal dystrophy, and nonvascularized scars. Topical cyclosporine and placebo were continued for 6 months. The duration of corticosteroid therapy and resolution of graft rejection episode, the number of concurrent and subsequent rejection episodes and the rate of rejection-free survival was compared between the study groups. Twenty-two eyes of 22 patients (12 men) received a combination of topical cyclosporine A 2% and betamethasone 0.1% (group 1) and 21 eyes of 21 patients (10 men) received topical betamethasone 0.1% and placebo (group 2) for an episode of recurrent graft rejection. Mean patient age was 32.48±11.9 and 35.48±11.7 years in group 1 and 2, respectively (P=0.42). Mean follow-up period was 16.6±6.1 months in group 1 and 16.0±6.3 months in group 2 (P=0.75). The episode for which topical cyclosporine 2% or placebo was started completely resolved after 25.6±21.0 and 33.2±16.7 days in group 1 and 2, respectively (P=0.22). The rejection-free graft survival rate was 34.8% in group 1 and 31.7% in group 2 (P=0.89). Adding topical cyclosporine A 2% had no further advantage over corticosteroid therapy alone to treat and prevent graft rejection in repeated rejection.

To report a case of acute myelogenous leukemia (AML) presenting with periorbital cellulitis and progressing to facial and neck cellulitis. Case Report: A 17 year old male patient presented with periorbital cellulitis which progressed to the right hemifacial and neck area. He did not respond to regular antibiotic therapy. Peripheral blood smear showed leukocytosis with predominance of immature cells, thrombocytopenia and anemia. Bone marrow biopsy confirmed a diagnosis of acute myelogenous leukemia. Acute leukemia must be considered in the differential diagnosis of periorbital cellulitis.

Orbital fat adherence syndrome is a known complication of strabismus, orbital and scleral buckling surgery or orbital trauma which induces a restrictive strabismus. In this case presentation we introduce a surgical method of globe slinging using temporalis fascia for correction of restrictive esotropia due to fat adherence syndrome. In our review of literature we found no report of a similar procedure using temporalis fascia.

Case report: A 9-year-old girl presented with a subconjunctival mass and ipsilateral preauricular lymphadenopathy. She had history of acute lymphoblastic leukemia (ALL) in remission but had a normal blood cell profile. Because of corneal dellen formation and enlargement of the mass over a 2-week period, resection of the lesion was performed. A relapse of acute lymphoblastic leukemia of pre B cell type (L1) was diagnosed on histopathologic examination of the excised mass. Bone marrow aspiration at that time disclosed medullary relapse of ALL. After systemic and intrathecal chemotherapy, the subconjunctival mass disappeared completely and the patient went to remission. Relapse of acute lymphoblastic leukemia may unusually presents as a subconjunctival mass despite a normal blood cell profile.