BINA
Year:2005 | Volume:11 | Issue:1 (42)|Papers Count:22

Purpose: To describe the methodology and implementation of the investigation for prevalence and causes of visual impairment in Tehran province.Methods: This population-based cross-sectional study was conducted on all urban and rural residents of Tehran province in 2003. A stratified cluster random sampling with probability proportional to size procedure was used. First, best pinhole-corrected visual acuity (BPCVA) was determined according to habitual visual acuity (VA) by an optometrist. Cases of BPCVA  £ 20/60 in either eye were referred to an ophthalmologist for detection of best spectacle-corrected visual acuity (BSCVA) and main cause of visual impairment (VA<20/60) including low vision (VA< 20/60-20/400) and blindness (VA< 20/400) according to BPCVA and BSCVA. Epidemiologic aspects and response rates in each phase of the study are presented.Results: Of 13 248 invited subjects, 11 975 persons participated in the first step of the study (primary response rate: 90.4%). Of these, 760 cases (6.3%) with BPCVA £ 20/60 were referred for ophthalmologic examination of which 557 participated in the study (secondary response rate: 73.3%). The study population in the first step consisted of urban subjects in 85% (approximately similar to the reference population) and female subjects in 61.4% (greater than the reference population, P<0.001). The proportion of the age group above 20 years, especially 20-29 years group in the study population was greater than that of the reference population. (P<0.001) Referral rate to ophthalmologists was 8.3% in urban and 6.0% in rural populations (P<0.001); 2.1% under age 20 years, 4.1% in age 20-49 years, and 24.7% in age ³ 50 years. (P<0.001) No children below the age 4 years were referred. The referral rate was not different between male (6.8%) and female (6.0%) subjects. Secondary participation rate was greater in male (85.8%) than female (64.4%) subjects (P<0.001), but there was no difference between rural and urban residents or between the age groups in this aspect.Conclusion: Despite good primary participation rate, the age and sex distribution of the study population was different from the reference population which highlights the need for planning an effective sampling procedure. The prevalence rates should be standardized for age and sex.

Purpose: To determine the prevalence of uncorrected refractive errors and its determinants in Tehran in 2002.Methods: A total of 6497 citizens representing a cross-section of the population of Tehran were sampled using a stratified random cluster sampling strategy. Of these, 4565 (70.3%) subjects participated in the study and were transferred to a clinic for an extensive eye examination and interview. The data obtained from 4354 participants aged five years and over are presented. The unmet need for eye glasses (the ratio of subjects who did not wear spectacles and had an uncorrected visual acuity worse than 20/40 in the better eye which improved to 20/40 or better with correction), the met need for eye glasses (the ratio of subjects with an uncorrected visual acuity worse than 20/40 in the better eye which improved to 20/40 or better with glasses), and glass coverage (met need/met + unmet need for eye glass) with 95% confidence interval (95% CI) were estimated.Results: The age- and gender- standardized prevalence of need for eye glasses was 14.1% (95% CI: 12.8-15.4). In 416 subjects (9.3%, CI: 10.4-12.8) the refractive error has been corrected with spectacles (met need), while 230 subjects (4.8%, 95% CI: 4.1 to 5.4) had an unmet need. The spectacle coverage rate was 66.0%. Unmet needs were greater in older, less educated, and myopic subjects.Conclusions: The prevalence of need for eye glasses in 5 years age or older population of Tehran is considerable and more than one-third of this need is not met properly. Older age, less education, and myopia are determinant factors of low glass-coverage.

Purpose: To determine the visual and anatomic outcomes of epikeratoplasty in 7 eyes of 6 patients with keratoglobus.Method: In a retrospective interventional case series, seven eyes of six patients with keratoglaobus (KGB) aged 5 to 39 years underwent epikeratoplasty. Three patients (3 eyes) had blue sclera, hypermobile joints, and consanguineous parents and 3 patients (4 eyes) had only KGB. In the blue sclera group, all patients had lost the fellow eye due to minor trauma. We used a 10.50 to 13.00 mm corneoscleral graft. Orbscan pachymetry was performed before surgery and 3 months after operation.Results: Mean visual acuity was 20/400 preoperatively and reached 20/160 postoperatively. Mean central corneal thickness was 200μ preoperatively which increased to 800μ after surgery. Epithelial inclusion cyst occurred in one patient. Severe interface vascularization occurred in one eye of the blue sclera group, which had total Descemet`s detachment before epikeratoplasty.Conclusion: Epikeratoplasty is a relatively safe, effective and reversible extraocular procedure for management of KGB. The procedure may be performed to produce corneal flattening and protect against acute corneal hydrops and perforation.

Purpose: To determine the prevalence of keratoconus (KCN) in patients with mitral valve prolapse (MVP).Methods: This descriptive study was conducted on patients with MVP at Shahid Rajaei Hospital during 2003-2004. Corneal topography was performed in 392 subjects with absolute mitral valve prolapse based on Perloff’s major criteria. Orbscan was carried out in suspected KCN cases.Results: Patient consisted of 247 men (63%) and 145 women (37%) with mean age of 37.27 ± 11.29 years. The diagnosis of two topographically KCN suspect patients was not confirmed with Orbscan. Positive family history of keratoconus in first-degree relatives was found in three patients. No cases of keratoconus were found.Conclusion: This study suggests that the prevalence of KCN in patients with MVP could be less than previously reported. A large multicenter study is needed to detect the association of these disorders. Genetic studies are suggested.

Purpose: To evaluate the prevalence, natural course, and final visual acuity in patients with stages III or IV of diffuse lamellar keratitis (DLK) following Laser in situ keratomileusis (LASIK).Methods: In this descriptive study, records of all the patients who underwent LASIK surgery in two private excimer laser clinics were reviewed. According to Linebarger- Lindstrom-Hardten classification, ocular findings of patients with DLK were classified. There was no preoperative systemic or corneal contraindication for LASIK. Age, preoperative refraction and best corrected visual acuity (BCVA), type and duration of treatment, postoperative refraction, topography, final BCVA, possible side effects of medications and complications were reviewed.Results: Out of 4097 eyes of 2131 patients, DLK above stage II developed in 28 eyes (0.68%) of 14 patients (0.66%). DLK was in stage II-III in 78.6%, stage III in 10.7%, and stage IV in 1.7%. None of these patients had history of allergies. Treatment consisted of frequent betamethasone drops alone or with ointment and oral systemic prednisolone. Interface irrigation was not performed in any patients during the course of treatment. Average interval from LASIK to diagnosis was 3±1.5 days. Patients were treated for an average duration of 20±13.2 days and were followed for an average duration of 11±10 months. Average preoperative BCVA was 0 Log MAR (20/20) and final post LASIK and DLK vision remained the same.Conclusion: Prevalence of DLK stages III and IV is considered insignificant as compared to the enormous number of candidates for LASIK surgery (0.68%). All patients with DLK stages III and IV responded well to immediate topical and systemic corticosteroid therapy and on follow up there was no adverse effect on final BCVA.

Purpose: To evaluate the visual outcomes of LASIK in myopic eyes.Methods: This interventional case series was performed on records of 345 eyes of 179 patients for correcting myopia with astigmatism < 3.00 diopter (D). All patients were operated by one surgeon (H.N.) with the NIDEK EC 5000 excimer laser. All patients had at least one year follow up. Based on preoperative refraction, patients were divided into four groups: low (-1.00 to -4.00 D), moderate (-4.00 to -7.00 D), high (-7.00 to -13.00 D), and extremely high myopia (> -13.00 D). Data including pre- and postoperative refraction, UCVA one year after surgery, pre- and postoperative BCVA, and range of emmetropia were analyzed in each group.Results: Mean preoperative spherical equivalent (SE) was -2.84±0.73 D in low myopia group, -5.12±0.84 D in moderate myopia group, -9.53±1.81 D in high myopia group, and -16.26±2.23 D in extremely high myopia group. The value decreased to -0.0845±0.16 D, -0.143±0.216 D, -0.467±0.34 D, and -2.385±1.49D, respectively at one year. The percentage of eyes according to range of ametropia were as follow: 94%, 83%, 40%, and 0% of eyes were within ± 0.25 D of emmetropia; 100%, 100%, 73%, and 15% of eyes were within ±0.5 D of emmetropoia; and 100%, 100%, 95.5%, and 23% of eyes were within ±1.0 D of emmerropia in each group, respectively. Postoperative UCVA of 20/40 or better was achieved in 100%, 100%, 98.4%, and 30.8% of eyes and UCVA of 20/20 or better was obtained in 78.9%, 73.1%, 31%, and 0% of eyes in the four groups, respectively. One year after LASIK, 2.1%, 0%, 6.7%, and 0% of the eyes lost two or more lines of BCVA in each group but 2.1%, 1.4%, 4.4%, and 7.7% of eyes gained more than one line of BCVA.Conclusion: LASIK is an effective and predictable procedure for correcting myopia. The predictability of LASIK decreases with increase in preoperative refractive error.

Purpose: To evaluate the results of laser in situ keratomileusis (LASIK) retreatment in patients with postoperative regression.Methods: In a retrospective interventional case series, 153 eyes of 113 patients who had undergone LASIK retreatment for postoperative regression were evaluated. Both initial LASIK and retreatment were performed with a Nidek: EC 5000 excimer laser and flap was made with a Moria microkeratome.Results: Mean age was 29.63 ± 2.2 yr (range, 20 to 54 yr) and mean follow–up was 11 months (range, 3 to 34mth) after the initial surgery and 13.1 months (range, 12 to 18mth) after retreatment. Retreatment was performed 3-34 months after the primary LASIK. Mean spherical equivalent (SE) was -5.39 ± 2.69 diopters (D) (range, -1.50 to -14.00 D) before initial LASIK and -1.76 ± 1.08 D (range, -0.50 to -5.00 D) before retreatment. Mean astigmatism was -1.38 ± 1.07 D (range, -0.50 to -5.00 D) before initial LASIK and -1.12 ± 0.50 D (range, -0.50 to -2.50 D) before retreatment. One year after retreatment, mean UCVA was 20/25, and mean SE was -0.29 ± 0.02 D. Best corrected visual acuity (BCVA) improved in all eyes. Two eyes received more than one retreatment. Twenty eyes had flap wrinkling, 2 eyes had diffuse lamellar keratitis (DLK), and 2 eyes had epithelial in growth after the initial LASIK. Four eyes had epithelial in growth and 2 eyes developed mild keratectasia after retreatment.Conclusions: LASIK retreatment is a safe and effective option with small amounts of myopia and myopic astigmatism regression. The rate of retreatment is higher in patients with myopic astigmatism and in patients with less than 40 years of age; also the risk of complications in retreatment is higher than the initial LASIK. Refractive changes are more stable after retreatment. The risk of keratectasia is higher in final residual stromal bed thickness less than 250 mm after the reoperation.

Purpose: To compare clear corneal incision and scleral tunnel incision in terms of intraocular pressure (IOP), post-operative inflammation, induced astigmatism, and corneal edema in phacoemulcification.Methods: This non-controlled clinical trial was conducted on 78 eyes with senile cataract. A clear corneal incision was made in 40 eyes and a scleral tunnel incision was made in 38 eyes. All eyes underwent standard phacoemulsification. Post-operative inflammation and corneal edema was measured 1, 7, and 60 days post-operatively. IOP was also measured preoperatively and 1, 7, and 60 days post-operatively. Corneal astigmatism was measured before and 7 and 60 days after surgery.Results: Post-operative inflammation was greatest on the first post-operative day in both groups, but there was no significant difference between them. In both groups, IOP was highest on the first postoperative day with no significant differences at any times of follow up. Mean decrease of IOP at 2 month comparing to preoperative value was 1.4 mmHg in the scleral tunnel group and 1.1 mmHg in the clear corneal group. Mean astigmatism preoperatively and on post-operative days 7 and 60 was 1.052±0.805, 0.993±0.653, and 0.730±0.527 diopter, and 0.893±0.850, 1.137±1.011, and 0.975±1.012 diopter in the scleral tunnel and clear cornea groups, respectively. Astigmatism on days 7 and 60 were grater in clear cornea incision. Against the rule induced astigmatism was more frequent in the clear corneal group. (p<0.04) In both groups, corneal edema was highest on the first post-operative day with no significant differences between the two groups.Conclusion: Scleral tunnel incision is better than clear corneal incision for minimizing postoperative corneal astigmatism in small incision cataract surgery.

Purpose: To compare orbscan II (O II) and ultrasound (US) pachymetry in normal and post-LASIK eyes.Methods: In a comparative prospective study, central corneal thickness (CCT) was measured in 168 eyes of 84 normal subjects and 42 eyes without corneal opacity of 21 post-LASIK patients by O II and US. Paired t test was used to identify significant differences between the two methods and Pearson test was used to identify the correlation of measurements between the two methods.Results: Mean CCT measured by ultrasound (538.7±47.4mm) was less than that of O II (542.7±52.2 mm) in the normal eyes (P<0.04), but mean CCT measured by ultrasound (477.8±38.2mm) was greater than that of O II (469.5±47.2mm) in the post-LASIK eyes. (p<0.02) There was significant linear correlation between US and O II in both groups. (r=0.87, P=0.000 and r=0.88, P=0.000, respectively).Conclusion: Mean difference of CCT measurements between O II and US in normal and post- LASIK clear cornea is not clinically significant and interchangeable use of data in planning or assessing corneal surgery is possible.

Purpose: To determine the incidence of retinopathy of prematurity (ROP) and to evaluate the possible neonatal risk factors for ROP among premature infants referred to Farabi Eye Hospital during 2000-2002.Methods: Newborn infants with gestational age (GA) £ 37 wk or birth weight (BW) £ 2500 g were included. The first eye examination was performed 4-9 weeks after birth. Data on possible risk factors include low birth weight, low gestational age, sepsis; supplemental oxygen therapy, blood transfusion, phototherapy, multiple pregnancy, and respiratory distress syndrome (RDS) were compared between the two groups of newborns with and without ROP. Univariate and multivariate analysis was performed.Results: One hundred eighty five neonates were included in this study (110 male, 75 female). Mean GA ± SD was 31.64 ± 2.67 wk and mean BW ± SD was 1620.68 ± 467.6 g. The incidence of ROP was 12.4% (95%CI: 7.6%-17.2%) including 8.6% in threshold and 3.8% in prethreshold stages. ROP was present in 18.6% of neonates with GA < 32 wk and 29% of neonates with GA < 28 weeks. All ROP cases had GA £ 33 wk. Mean GA ± SD was 29.39 ± 2.16 wk in the ROP group and 31.96 ± 2.58 wk in the non-ROP group. (P< 0.001) Mean BW ± SD was 1283.48 ± 342.84 g in the ROP group and 1668.55 ± 464.04 g in the non-ROP group. (P< 0.001) ROP was present in 20.5% of neonates with BW £ 1500 g. All ROP cases had BW £ 2000 g. There was a significant association between blood transfusion and incidence of ROP (odds ratio= 3.75, P= 0.004), RDS (OR= 3.14, P=0.041), and phototherapy (OR= 2.86, P= 0.044) based on univariate analysis. There was no significant association between oxygen therapy and incidence of ROP. Based on multivariate logistic regression analysis, low GA was the only significant factor associated with high incidence of ROP.Conclusion: We suggest GA £ 33 wk and BW < 2000 g as the best criteria for screening of high risk neonates for developing ROP. These criteria deserve further investigation.

Purpose: To evaluate the effect of intravitreal triamcinolone acetonide (IVT) reinjection on clinical and optical coherence tomographic (OCT) features in refractory diabetic macular edema (DME).Methods: In an interventional case series, all IVT-treated patients enrolled in a previous clinical trial (45 subjects), were recalled for performing a new ophthalmologic examination and OCT. Suitable eyes for reinjection received 4 mg IVT. Complete ophthalmologic examination and OCT were performed after two and four months.Results: From 45 recalled patients, 23 were included for the new study (51.1% response rate). Of these, only 12 cases were considered as candidates for reinjection. Visual acuity (VA) changes were not significant in the reinjected eyes after both the first and the second interventions, although there was a relative improvement (0.14 log MAR) at two months after the first injection. Central macular thickness (CMT) was reduced by 27 and 49 m   two and four months after the reinjection and 43 and 40 m at two and four months after the first injection. None of the mentioned changes was significant. IOP elevation was significant two and four months after the second injection (3.6 and 2.4 mmHg, respectively, P<0.05). However, it was significant (5.58 mmHg, P=0.001) only two months after the first injection.Conclusion: The transient beneficial effects of IVT on refractory DME are not repeated with second injections. However, IVT-related ocular hypertension is more persistent after reinjection.

Purpose: To evaluate the efficacy of radial optic neurotomy (RON) combined with or without intravitreal triamcinolone acetonid (IVTA) injection in the management of central retinal vein occlusion (CRVO).Methods: This non-randomized clinical trial was conducted on 23 patients with CRVO, who underwent RON with or without IVTA injection. Preoperative and postoperative best corrected visual acuity were converted to Log MAR and time to plateau of best corrected visual acuity were evaluated over a 12 months period.Results: The patients included 16 male and 7 female subjects with mean age of 56±16.8 year (25-72 years). Mean visual acuity was 1.42±0.43 Log MAR (20/600) preoperatively, which improved to 1.1±0.14 Log MAR (20/250) postoperatively. (P<0.05) At one year, mean visual acuity was 1.56±0.63 Log MAR in the non-IVTA group and 1.09±0.37 Log MAR in the IVTA group (P= 0.04). Vision improved by 3 or more lines in 14 eyes (60.9%). Overall eyes with combined RON and IVTA injection had better postoperative visual acuity, although it was not statistically significant. Time to plateau of best-corrected visual acuity in eyes that underwent RON combined with IVTA injection was significantly shorter.Conclusion: The combination of RON and IVTA injection may enhance therapeutic success and cause faster visual rehabilitation than RON alone.

Purpose: To evaluate the effect of Botulinum toxin-A (BTA) injection into the inferior oblique (IO) muscle in releaving the symptoms of superior oblique (SO) palsy.Methods: The study was conducted on patients who were referred for acquired SO palsy with less than 2 years of duration. About 10-20 unit of BTA was injected into the belly of the inferior oblique muscle through the inferotemporal quadrant of the involved eye without opening the conjunctiva.Results: Eighteen eyes from 16 patients were injected. Mean age was 33.7 years and mean duration of paresis was 6 months. Trauma was the cause of paresis in 81.2%. Six months after the injection, mean deviation decreased from 6.4D to 1.9D; mean IO over-activity decreased from +1.7 to +0.6; mean SO upper-activity decreased from -1.5 to -0.4; mean subjective torsion decreased from 9.30 to 0.40; and mean head tilt decreased from 8.40 to 1.10.Conclusion: Botulinum toxin-A injection into the IO muscle can decrease the symptoms of patients with SO palsy and cause faster rehabilitation of these patients before stabilization of signs for final decision.

Age related macular degeneration (AMD) is the most common cause of visual impairment in the population above 64 years of age in developed countries. Most cases of severe vision loss due to AMD are caused by exudative changes in the macula. Extensive research on AMD has led to advances in its prophylaxis and treatment in recent years. Photodynamic therapy (PDT) was developed in late 1990's in which free oxygen radicals damage the neovascular tissue in a nonthermal way. The first prophylactic treatment for AMD was approved in 2001 which includes oral administration of a combination of vitamins, antioxidants, and minerals. It was shown that this treatment decreases the chance of progression of dry type AMD to more advanced atrophy and choroidal neovascularization. Laser treatment for drusen is currently under investigation. Vitrectomy for removal of subretinal choroidal neovascularization (CNV) has proven not to be effective for visual improvement. Translocation of fovea to an area away from CNV has met some success but the chance of loss of peripheral vision has hampered its general acceptance. An important area of research is the pharmacologic approach to counteract choroidal neovascularization. Three groups of anti-angiogenic agents have been studied; 1) anti-VEGF (vascular endothelial growth factor), 2) recombinant anti-VEGF antibodies, and 3) steroids. Transpupillary thermotherapy has been used for several years and was claimed to be effective for treatment of CNV in some small uncontrolled studies but failed to be more effective than sham treatment in a recent multicenter controlled trial. In general, it seems that the most promising areas of research in the treatment of AMD are prophylactic treatment and antiangiogenic therapy.

Purpose: To report a case of ciliary body medulloepithelioma presenting as granulomatous uveitis.Patient and finding: A 3-year-old girl presented with chronic granulomatous anterior uveitis in the right eye following unilateral cataract extraction and IOL implantation which was unresponsive to topical steroids and intra-vitreal injection of vancomycin and triamcinolone acetonide. One month later, white masses appeared over the iris surface. Histopathologic examination of the iris biopsy disclosed ciliary body medulloepithelioma. The patient was referred for plaque therapy due to the aggressive behavior of the tumor and finally, the eye was enucleated due to getting blind and painful and high suspicious of malignant behavior of the tumor.Conclusion: Medulloepithelioma is a rare congenital ciliary body tumor that presents with decreased vision, pain, leukocoria, and observation of a mass in the region of the ciliary body, anterior chamber and iris. Secondary glaucoma, cataract, uveitis, rubeosis iridis, retinal detachment, and ectopia lentis may develop later. The tumor may be locally aggressive and rarely metastasize. If extraocular extension does not occur, iridocyclectomy with tumor excision (in small tumors) and enucleation (in large tumors) appears to be the treatment of choice.

Purpose: To report a rare case of ciliochoroidal malignant melanoma presenting as a subconjunctival black-colored mass adjacent to the limbus.Patient and findings: A 42-year-old woman presented with a subconjunctival black-colored mass adjacent to the limbus in left eye from 2 years ago. The lesion had increased in size during the previous 2 months. Funduscopic examination with scleral depression disclosed a small mass at the cilioretinal junction. Gonioscopy revealed that the superior portion of the angle was occupied by the mass. Visual acuity and intraocular pressure were normal. Other systemic examinations were unremarkable. Because of extensive extraocular extension of the tumor, the left eye was enucleated and histopathologic examination of the globe disclosed a highly pigmented medium-sized ciliochoroidal malignant melanoma of mixed cell type together with marked anterior extrascleral extension. Results of 6-month follow-up for metastasis were negative.Conclusion: A darkly pigmented epibulbar mass may be the first manifestation of ciliochoroidal malignant melanoma.

Purpose: To report a case of enophthalmos secondary to complete globe dislocation into the maxillary sinus due to orbital fracture.Patient and Findings: An 18-year-old man was referred to Labafinejad hospital, one week after a car accident. At initial examination, the globe was not seen within the right orbit. A large floor fracture and globe luxation into the right maxillary sinus was confirmed on CT scan. Repair of the fracture using Medpore implant and globe repositioning were performed. Visual acuity following surgery was no light perception without improvement during follow-up.Conclusion: Visual impairment in this case was most probably due to traumatic optic neuropathy and delayed surgical intervention and medical therapy with systemic corticosteroid.