BINA
Year:2008 | Volume:13 | Issue:3 (52)|Papers Count:17

Purpose: To determine the prevalence of amblyopia and its determinants in students of region 1 in Mashhad, 2oo6.Methods: Using randomized cluster sampling, 2510 students were selected to undergo ophthalmologic examinations. Amblyopia was defined as corrected visual acuity of 8/10 or less in either eye.Results: Of the 2510 selected student, 2150 were examined (85.6% participation rate). The prevalence of amblyopia was 1.9% (95% confidence interval [CI], 0.94 to 2.9) including 2.1% in female and 1.7% in male subjects (P=0.620). Amblyopia was detected in right eye in 31.7%, left eye in 41.5% and both eyes in 26.8%. About 66% of amblyopic cases had refractive errors.Conclusion: The prevalence of amblyopia in students of region 1 in Mashhad is comparable to that of other parts of the country. Refractive error is a significant risk factor for occurring amblyopia.

Purpose: To report the results of different methods for true corneal power and intraocular lens (IOL) power calculation in 10 eyes with previous radial keratotomy (RK) with or without astigmatic keratotomy.Methods: In this case series including 10 eyes of 7 patients who had undergone RK with or without astigmatic keratotomy, we firstly determined corneal power using two methods: contact lens method (CLM) and mean keratometry of 3 mm zone in topography. In the next step, 10L power of these eyes was calculated using three formulas including SRK II, SRK T and Holladay II, but the results of Holladay 11formula were used as determinant of 10L power during cataract surgery. Since 1.50 diopter change in 10L power results in 1.00 diopter change in patient's refraction at spectacles plane, we estimated the manifest refraction of these eyes with other formulas for comparing with the results of Holladay 11formula three months after cataract surgery.Results: Postoperative manifest refraction in 8 eyes by using CLM ranged from -3.00 to +2.00 diopter. In both CLM and mean keratometry of 3 mm zone in topography, the amount of hyperopia after cataract surgery with SRK II formula was more than SRK T, and with SRK T was more than Holladay II. Mean spherical equivalent was 0.08 diopter in mean keratometry of 3 mm zone in topography and Holladay 11formula and -0.05 diopter in CLM and Holladay II formula indicating adequate precision of these two methods.Conclusions: It seems that after RK, mean keratometry of 3 mm zone in topography yield a precise estimate of true corneal power as compared to CLM and that Holladay 11formula has the most exact result closer to emetropia in comparison with SRK11and SRKT formulas.

Purpose: To compare the efficacy of adding an opposite clear corneal incision (OCCI) on the steep axis during phacoemulsification in reducing the pre-existing corneal astigmatism.Methods: This randomized clinical trial was performed on 120 eyes with corneal astigmatism of >1D undergoing phacoemulsification. Incisions were made based on the type of astigmatism as follows: superior or superior+OCCI in the with-the-rule and temporal or temporal+OCCI in the against-the-rule astigmatism. Patients were followed with refraction, keratometry and topography. Statistical analyses were done using one and two ways ANOV A and Tukey-a test.Results: Mean corneal astigmatism was 1.82±0.86 D in the superior+OCCI group and 1.74±0.86 D in the temporal+OCCI group preoperatively which respectively decreased to 1.31±0.59 (P= 0.013) and 1.19±0.64 (P= 0.009) postoperatively. No significant changes occurred in the amount of astigmatism in none of the two single incision groups.Conclusion: Paired OCCI on steep axis is a useful technique to correct mild to moderate pre-existing astigmatism with no need to extra skill or instrumentation.

Purpose: To compare the results of implantation of intraocular lens (IOL) haptics in ciliary sulcus versus optic capture through the posterior capsulorrhexis following IOL implantation in capsular bag in pediatric cataract surgery.Methods: Eighteen eyes of nine children with bilateral congenital or developmental cataract were included in this contralateral prospective randomized study. All cases underwent anterior capsulorrhexis, lens aspiration, posterior capsulorrhexis and anterior vitrectomy. In one eye, IOL (Acrysof MA60BM) was implanted in capsular bag and in the follow eye, IOL haptics were implanted in ciliary sulcus and optic was captured through the posterior capsulorrhexis. Position of the IOL in the first eye was randomly selected. Best-corrected visual acuity (BCVA), visual axis opacification and possible complications were evaluated.Results: Mean age of the patients was 5.1±1.7 (range 2.5-8) years. Patients were followed for 25.6±5.2 (range 18-35) months. There was no statistically significant difference between the two groups in term of BCVA. Visual axis remained clear in all cases of both groups. Early postoperative fibrin formation was seen in two eyes of each group. There was no significant IOL decentration in any cases.Conclusion: Posterior capsulotomy followed by anterior vitrectomy and implantation of hydrophobic acrylic IOL in pediatric cataract surgery significantly decreases secondary opacification of visual axis. In the cases with difficult or impossible implantation of IOL in the capsular bag, implantation of haptics in ciliary sulcus and IOL optic capture through posterior capsulorrhexis is a safe alternative method.

Purpose: To report the result of limbal autografting in primary and recurrent pterygium.Methods: In this case series, all patients who were referred to our clinic at Farabi hospital, Isfahan, Iran for treatment of pterygium were included. Indications of surgery included chronic ocular irritation, impaired or threatened vision, ocular motility problem and cosmetic reasons. Under subconjunctional anesthesia, pterygium was removed from the cornea and conjunctiva and a crescent shape limbal tissue from supratemporal region of the same or the sound eye was then prepared and sutured in the area of pterygium removal. In cases with conjunctival problem due to previous surgery or severity of the disease, some amount of conjunctival tissue was also included in the transplanted limbal tissue. Postoperatively, topical betamethasone for 4 weeks and antibiotic for 2 weeks were prescribed.Results: Two-hundred and three eyes were studied of which, 125 eyes (61.6%) had primary and 78 eyes (38.4%) had recurrent pterygium. After at least one year of follow-up, only 9 eyes (4.5%) had recurrence larger than 1 mm. Visual acuity and refraction improved in 60% of the eyes. No significant complication occurred except appearance of a fibrous tissue in the donor site which was not progressive and was covered by the upper lid in all cases.Conclusions: Surgical removal together with limbal autograft is a safe and effective method for treatment of primary and recurrent pterygium.

Purpose: To investigate the risk factors of wound dehiscence and lens extrusion following blunt trauma in patients with penetrating keratoplasty (PK) as well as the results of treatment.Methods: In a retrospective case series, 7 eyes of 7 patients including 6 male and one female subject were investigated. All cases received primary care at the time of referral and then underwent secondary repair under general anesthesia in operation room setting. After evaluation of the wound, anterior vitrectomy was performed and secondary wound repair was done using nylon 10-0.Results: Mean age of patients was 20.6±6.2 (range 10 to 30) years and mean interval between keratoplasty and trauma was 15.6±10.1 (range 2.5 to 26.5) months. Mean best-corrected visual acuity of patients before the trauma and at final follow-up was 0.6±0.38 logMAR (20/80) and 0.9±0.96 logMAR (20/160), respectively. In one case, visual acuity decreased to light perception after the final treatment. No case needed re graft. Most prevalent site of dehiscence was superior to the graft (4 cases) and the most prevalent cause of blunt trauma was hitting by hand. No case of endophthalmitis occurred.Conclusion: PK patients are susceptible to wound dehiscence due to trauma especially during the first postoperative year. This is more prevalent in young male subjects who are more prone to trauma because of higher social activities. Proper explanation of this problem for patients together with using protective eye shields as well as performing lamellar keratoplasty instead of PK if possible can decrease side effects of trauma in these patients.

Purpose: To evaluated the correlation between intracranial pressure (ICP) and intraocular pressure (IOP).Methods: This interventional case series included 90 patients undergoing lumbar puncture (LP) for neurologist evaluation. IOP was measured before and 1 hour after the LP by using Goldmann tonometer.Patients were compared into two groups: patients with normal ICP (<20 CmH2O) and patients with high ICP (³20 CmH2O).Results: Patients included 29 male and 61 female subjects with mean age of 32.9 ±11.4 (range 13-62) years. Thirty-three patients had normal ICP and 57 patients had high ICP. There was a significant correlation between ICP and IOP such that 71.9% of the high ICP group had high IOP (³21 mmHg) and 28.1% of them had normal IOP (P<0.001). Significant decrease in IOP occurred after LP in the high ICP group (P< 0.001).Conclusions: It seems that there is a significant correlation between IOP and ICP.

Purpose: To evaluate the correlation between retinal nerve fiber layer (NFL) thickness and visual field parameters in patients with optic atrophy.Methods: This study was performed on 35 eyes of 28 patients with optic atrophy. NFL thickness was measured by optic coherence tomography (OCT) and visual field analysis was performed by Humphrey perimetry. The correlation between NFL thickness and visual field parameters was evaluated.Results: Mean NFL thickness was 44.9±27.5 m which was significantly correlated with mean deviation of perimetry (r=0.493, P=0.003); however, no significant difference was found between quadrant NFL thickness and corresponding visual field pattern standard deviation. No significant correlation was found between visual acuity and NLF thickness.Conclusion: Similar to visual field, OCT can be used as an objective diagnostic tool in optic atrophy suspected patients.

Purpose: To evaluate the success rate of Nd: YAG laser membranotomy in patients with diabetic premacular hemorrhage.Methods: This interventional case series included 24 eyes of 22 patients referred to retina clinic of Farabi Eye Hospital, Tehran, Iran during 2000-2007 with chief complaint of sudden loss of vision and clinical diagnosis of premacular hemorrhage due to proliferative diabetic retinopathy. All patients underwent complete ocular examination and color fundus photography. Nd: YAG laser membranotomy was performed in patients with ³3 DD hemorrhage. Main outcome measures were success rate of membranotomy, improvement of visual acuity and the complications.Results: Twenty-four eyes of 22 patients (68.2% female and 31.8% male) with diabetic premacular hemorrhage were enrolled. Mean age of patients was 56±6.5 years. Nd: YAG laser membranotomy was successful in 71% of patients resulting in release of trapped blood into the vitreous cavity which absorbed during 14.3±5.03 (range 8 to 27) days. Range of preoperative visual acuity was from hand motion to count finger at 4 m which improved to a range of 20/100 to 20/25 postoperatively. Patients complained of some visual disorders such as blurred vision and floater over 23-86 days (mean 43 days), postoperatively. Macular photocoagulation was performed in 11 eyes with macular edema before panretinal photocoagulation. Mean follow-up period was 34.7±18.3 (range 10-71) months.Conclusion: Nd: YAG laser membranotomy in diabetic premacular hemorrhage is a simple and inexpensive outpatient procedure which results in rapid visual recovery and is relatively safe. Further controlled clinical trials are recommended.

Purpose: To evaluate the histopathologic features of trabeculectomy specimens and the results of trabeculectomy in relation with these features in patients with chronic primary glaucoma.Methods: This interventional case series included 30 eyes of 28 patients with primary chronic glaucoma who underwent trabeculectomy between 2004 and 2006. Each case was followed for 6 months postoperatively. Histopathologic features and results of surgery were evaluated. The surgery considered as successful when resulted in intraocular pressure (IOP) <21 mmHg without antigiancoma medication and as failed when resulted in IOP of > 21 mmHg and need to anti-glaucoma agent.Results: Mean age of patients was 59 (range 20 to 90) years and 18 patients (64.3%) were male. Seventeen patients had chronic primary open angle glaucoma and 11 had primary chronic closed angle glaucoma. The operation was performed as fornix-based method in 16 eyes and limbal-based in 14. The surgery was successful in 26 (86.7%) and failed in 4 (13.3%). The content of trabeculectomy specimens in the successful cases included trabecular meshwork in 15 (57.7%), only scleral in 6 (23.1%) and only corneal tissue in 5 (19.2%) cases. Out of 15 cases with content of trabecular meshwork, 7 cases (26.9% of successful cases) had all three portions of cornea, trabecular meshwork and sclera. This figure was not observed in any failed cases. The content of trabeculectomy specimens in failed cases included trabecular meshwork in 3 cases and only sclera in one case.Conclusion: The size and position of the site of trabeculectomy is variable and seems to have significant effects on the success rate of the surgery such that surgical resection anterior to the scleral spur increases the chance of surgical success.

Purpose: To evaluate the clinical features of Duane's syndrome in patients who were referred to Nikookari Eye Centre, Tabriz, as a referral centre of northwest of Iran.Methods: We retrospectively reviewed medical records of all patients with Duane's syndrome who were referred to the strabismus clinic of our center during a 5-year period (2002-2006). Clinical and demographic characteristics were evaluated.Results: Overall 63 patients including 36 (57.1%) female and 27 (42.9%) male subjects were enrolled which account for 2.5% of patients referred for any type of strabismus. Mean age at presentation was 10.1±7.7 (range 1-35) years. Left, right and both eyes were involved in 60.3%, 25.4% and 14.3%, respectively. The most common type of Duane's syndrome was type I (91.6%) followed by type II (6.6%) and type III (1.6%). The most common presenting sign was eye deviation. The prevalence of amblyopia was 19% and 47.6% of patients underwent surgery.Conclusion: The rate of surgical intervention and the frequency of type ID Duane's syndrome was very low is our series as compared to other published studies.

Purpose: To report bilateral Terrien's marginal degeneration, circumferential peripheral corneal ectasia and posterior polymorphous dystrophy in a patient with rheumatoid arthritis.Case Report: A 24-year-old male patient, who was known case of rheumatoid arthritis from 8 years before, presented with decreased vision since four years ago. Comprehensive ophthalmic eye examination revealed bilateral circumferential peripheral corneal thinning and bulging with vascularization and lipid deposition in addition to band-like lesions in Descemet's membrane. Previous records revealed no gross abnormalities up to four years ago. Corneal lesions were consistent with bilateral circumferential Terrien's marginal degeneration concomitant with posterior polymorphous dystrophy.Conclusion: To our knowledge, this is the first report of concomitant bilateral Terrien's marginal degeneration with total peripheral corneal ectasia and posterior polymorphous dystrophy in a patient with rheumatoid arthritis. Circumferential involvement, younger age at presentation and bilateral total peripheral corneal ectasia in this case are not typical for classic Terrien's marginal degeneration. The underlying rheumatoid arthritis may have aggravated the condition leading to this atypical and severe presentation of Terrien's marginal degeneration.

Purpose: To report a patient with Fuchs' heterochromic iridocyclitis and pellucid corneal marginal degeneration.Case Report: A 37-year-old woman referred to Poostchi Eye Clinic, Shiraz, Iran with complaint of low vision in both eyes especially in the left side since many years ago. On ophthalmologic examination, best-corrected visual acuity was 20/50 in right eye with refraction of -6.50-7.5@900 and 20/80 in left eye with refraction of -8.50-11.00x900. Slitlamp examination revealed inferior thinning of cornea in both eyes and diffuse keratic precipitates on corneal endothelium, 1+ cell and flare in the anterior chamber and posterior subcapsular cataract in left eye. There was a moderate iris hetererchromia between the eyes which beside other findings was suggestive of Fuchs' heterochromic iridocyclitis. Corneal topography was in favor of pellucid marginal degeneration.Conclusion: To our knowledge this is the first case of pellucid marginal degeneration associated with Fuchs' heterochromic iridocyclitis in the literature. This may be a co-incidence or might have occurred due to a defect in embryonic ocular development.