BINA
Year:2011 | Volume:16 | Issue:3 (64)|Papers Count:16

Purpose: To estimate the magnitude and causes of visual impairment (VI) in subjects aged³50 years in Varamin district in 2009 using the proposed method by the World Health Organization (WHO).Method: This cross sectional population based survey was performed in Varamin targeting people over the age of 50 years using the proportional probabilities to size and cluster compact segment sampling method.Blindness was defind by WHO definition as best corrected visual acuity (VA) in the better eye less than 3/60. Severe visual impairment (SVI) and visual impairment (VI) were defined as 3/60£VA<6/60 and 6/60£VA<6/18 in the better eye, respectively. The cause of visual impairment was determined in any eye with VA<6/18. The results were analyzed by RAAB software.Result: Among 3, 000 selected patients, 2, 819 persons (94% response rate) including 45.7% men and 54.3% women were examined. The standardized prevalence of blindness, severe visual impairment (SVI) and visual impairment (VI) were 1.33±0.43, 1.34±0.55 and 6.84±0.95, respectively. More than 75% of causes of blindness, SVI and VI were avoidable. The principal cause of blindness and SVI was cataract; although, in VI it was refractive errors.Conclusion: The majority of blindness and VI was due to avoidable causes. Cataract and refractive errors were the main causes in the studied population.

Purpose: To determine the anatomical sites and causes of severe visual impairment (SVI) and blindness in children attending a school for the blind in Ahvaz.Methods: In this case series study, all 51 students of the only school for the blind in Ahvaz were examined by two ophthalmologists. Blindness and SVI were defined according to the World Health Organization (WHO) criteria as visual acuity less than 3/60 and 6/60, respectively. Visual acuity was measured by snellen chart; slit lamp biomicroscopy and dilated fundus exam were performed for all children.Results: Of 51 examined students aged 7 to 16 years, one child was not visually handicapped and therefore excluded. Causes of blindness and SVL in 50 students (100 eyes) in order of frequency were: optic atrophy 7 (14%), retinitis pigmentosa 7 (14%), chorioretinal coloboma 6 (12%), severe myopia 4 (8%), macular dystrophy 4 (8%), old retinal detachment 1 (2%), cataract 5 (10%), microcornea 6 (12%), corneal opacity 4 (8%), persistent hyperplastic primary vitreous (PHPV) 1 (2%) and hypotonia and phthysis bulbi 5 (10%).Conclusion: The most common causes of SVI and blindness were rare inheritable causes including congenital disease of the retina, optic nerve and cornea which resembles the pattern of childhood blindness in developed countries.

Purpose: To evaluate the microbiological characteristics of lid margin flora in chronic blepharitis in individuals exposed to mustard gas in comparison to nonexposed patients.Methods: In this case-control study, among 289 patients with documented ocular manifestations of mustard gas, 150 patients with clinical sings of blepharitis served as the case group. Microbiologic evaluation was conducted in these patients and compared to that of 100 unexposed patients with chronic blepharitis.Results: In 150 patients with mustard gas exposure and chronic blepharitis, staphylococcus epidermidis (78%) and staphylococcus aureus (57%) were significantly higher than control group (P<0.01). Moreover, staphylococcus aureus had more resistance to common antibiotics in the case group. Fungi were isolated more frequently in cases compared with controls (30% vs.4%, P<0.01). Cladosporium and Candida were the most common species.Conclusion: Microbiological evaluation in patients with chronic blepharitis associated with mustard gas is significantly different from other patients. Staphylococcus spp, including strains resistant to Methicillin, and fungi were more frequently isolated in exposed patients. The relationship between microbial culture and the severity of ocular manifestations in mustard gas exposed cases warrants further investigation.

Purpose: To characterize keratic precipitate (KP) morphology in different forms of uveitis.Methods: One hundred and twenty nine eyes of 93 patients with different forms of uveitis underwent confocal scan and the morphology of KPs were determined. Differences in KP morphologies among different uveitic groups were evaluated.Results: Age ranged from 14 to 67 years (mean: 32.5±11.2) and 58 cases (62.36%) were female, 38.7% had bilateral uveitis. Almost all types of uveitis disclosed predominantly stippled and globular KPs.Dendritiform KPs were more common in infectious uveitis (P=0.053) and smooth-rounded KPs were significantly more common in non-infectious uveitis (P<0.001).Dendritiform KPs were observed more commonly in nongranulomatous uveitis than granulomatous ones (P=0.005). Smooth-rounded KPs were more common in chronic uveitis than acute forms (P<0.001).The predominant morphology of KPs in Fuchs heterochromic iridocyclitis (FHIC) were dendritiform (80.0%) and infiltrating (78.0%). The most commonly observed morphology of KPs in intermediate uveitis were dendritiform (56.3%) and smooth-rounded (56.3%). Cruciform KPs were more frequently seen in cases with FHIC (60.0%). Morphologic features in bilateral cases were similar.Conclusion: KP morphologies are diverse in different forms of uveitis. Some forms of KPs are less specific such as globular and stippled which exist in almost all types of uveitis. Confocal scan can playa potential role in differentiating infectious from noninfectious uveitis and granulomatous from nongranulomatous uveitis.

Purpose: To evaluate refractive state in patients with unilateral congenital nasolacrimal duct obstruction.Methods: In this descriptive prospective study, patients with unilateral congenital nasolacrimal duct obstruction scheduled for surgery were enrolled over a period of two years (2007-2009). Cycloplegic refractive error in both eyes was measured under anesthesia before surgery (probing, silicon intubation or dacryocystorhinostomy). When more than one procedure was required, only the first refraction was considered for analysis.Anisometropia greater than 0.5 diopter was defined as clinically significant.Results: Ninety-four patients with mean age of 25.4±20.4 months (range: 6 month to 10 years) entered the study. In older ages the prevalence of clinical signs secondary to nasolacrimal obstruction such as discharge and epiphora increased, however, this was not statistically significant (r=0.115 & P=0.270). Spherical equivalent refractive error in 78(83%), 8(8.5%) and 8(8.5%) affected eyes was hyperopic, myopic and emmetropic, respectively.Corresponding figures in unaffected eyes were 67(71.3%), 22(2304%) and 5(5.3%), respectively. The prevalence of anisometropia greater than 0.5 D was 25% and that of less than 0.5 D was 43%. Anisometripia was not present in 32% of patients. Each month increase in patient's age was associated with 0.007 D higher difference in spherical refractive error between two eyes (P=0.019). For cylindrical refractive error, this change was negative and non-significant (P=0.291) and for spherical equivalent it was positive but non-significant (P=0.137). In older ages, more surgeries were needed (r=0.297, P=0.004).Conclusion: Anisometropia increase with age and more time is necessary to relieve the obstruction during surgery. Anisometropia specially anisohyperopia in older subjects becomes more common and also difficult to treat. Early refraction and intervention help to prevent amblyopia and may reverse the anisometropia.

Purpose: To evaluate the effect of ocular dominance on stereoacuity in experimentally induced anisometropia.Methods: In this clinical trial, 60 healthy adult volunteers 18-37 years of age (mean age: 25.58 years) without any ocular disease were emolled at Tabriz Nikookari eye hospital over a one-year period. Anisometropia (unilateral myopia) was induced by placing trial lenses over the dominant and non-dominant eyes in 1 diopter (D) increments ranging from 1-3 D. Stereoacuity was measured using the TNO, Randot and Titmus stereotests and values were converted into Neperian logarithm (In) and compared between the two eyes.Results: Of sixty adults including, 25 male and 35 female subjects, the right eye was dominant in 49 (81.7%) of cases. Stereoacuity levels were reduced proportionate to the degree of anisometropia in all participants.Mean stereoacuity was 4.3, 5.5 and 7.4 In for dominant eyes and 4.1, 5.4 and 7.3 In for non dominant eyes usig the TNO test by applying 1, 2 and 3 D lenses, respectively (P>0.05). Corresponding values were 3.5, 4.6 and 6.6 In for dominant eyes and 3.4, 4.6 and 6.5 In for non dominant eyes by the circles subcategory of Randot test, respectively (P>0.05). The scores were 3.8, 4.7 and 6.5 In for dominant eyes and 3.8, 4.7 and 6.4 In for non dominant eyes by the circles subcategory of Titmus test, respectively (P>0.05).Conclusion: Experimentally induced anisometropia could reduce stereoacuity. However, ocular dominance has no effect on the amount of stereoacuity reduction.

Purpose: To compare the results of intravitreal bevacizumb (NB) injection alone or in combination with intravitreal triamcinolone acetonide (IVT) versus macular laser photocoagulation (MPC) as primary treatment of diabetic macular edema (DME).Methods: In this randomized clinical trial, 150 eyes of 129 patients with clinical DME and no previous treatment were enrolled. The eyes were randomly assigned to one of the three study arms: the IVB group received 1.25 mg IVB (50 eyes); the IVB/IVT group received 1.25mg of IVB and 2 mg of IVT (50 eyes); and the MPC group underwent focal or modified grid laser (50 eyes). Retreatment was performed at 12-week intervals whenever indicated.Results: Visual acuity (VA) changes among the groups were statistically significant at 6 (P<0.001) and 24 (p=0.012) weeks. VA change was significant only in the IVB group at 12 weeks. VA changes±standard deviation at 36 weeks were -0.28±0.25, -0.04±0.33, and+0.01±0.27 LogMAR in the NB, NB/IVT, and MPC groups, respectively (P=0.053). Significant reduction in central macular thickness (CMT) was observed in all groups only up to 6 weeks; however, CMT changes were not significantly different among the groups in all visits. Overall, retreatment was required for 27 eyes up to 36 weeks (14 in the IVB group, 10 in the IVB/IVT group, and 3 in the MPC group). In the IVB group, in which greater VA improvement was observed, only one injection was required in 72% of the cases. VA improvement more than 2 Snellen lines at 36 weeks occurred in 37%, 25%, and 14.8% of patients in the NB, IVB/IVT and MPC groups, respectively.Conclusions: Intravitreal bevacizumab injection in patients with DME yielded a better visual outcome at 24 weeks compared with macular photocoagulation. After 6 weeks changes in CMT and VA were not compatible. No adjunctive effect of IVT was demonstrated.

Purpose: To compare anterior segment and ocular biometric parameters of unaffected fellow eyes of patients with a previous attack of acute angle closure (AAC), primary angle closure suspect (PACS) eyes, and normal eyes; and to assess the risk of developing AAC in PACS.Methods: In this prospective comparative observational case series, 16 unaffected fellow eyes of patients with a previous attack of AAC (group I), 40 PACS eyes (group II) and 32 normal eyes (group III) were evaluated. Pentacam and A-scan echography were performed in all cases. Anterior chamber angle (ACA), anterior chamber volume (ACV), anterior chamber depth (ACD), central corneal thickness (CCT), keratometry (KR), lens thickness (LT) and axial length (AL) were measured in all eyes as main outcome measures.Results: Age, CCT and LT were comparable among the study groups (all P values>0.05). Mean ACA was 24.8o, 22.9o and 35.4o in groups I, II, and III respectively (P<0.001). Corresponding values for ACV were 72, 76 and 172ml, respectively (P<0.001). Central ACD measured from the endothelium was 1.80, 1.91, and 3.09 mm in groups I, II, and III respectively (P<0.001). Using receiver operating characteristic (ROC) curves, ACV£100 ml was associated with a high risk of AAC with sensitivity of 91.7% [95% Confidence Interval (CI): 70 to 99] and specificity of 100% (95% CI: 89 to 100). Corresponding values for ACA ~25° were 75% (95% CI: 51 to 90) and 93.3% (95% CI: 79 to 98); and for ACD£2.1 mm were 86.7% (95% CI: 62 to 96) and 100% (95% CI: 89 to 100) respectively. If two of these three criteria (ACV£100 ml, ACA £25o and ACD£2.1 mm) are present, the eye can be considered at high risk for an attack of AAC with sensitivity of 93.3% (95% CI: 70 to 99) and specificity of 100% (95% CI: 89 to 100).Conclusion: Eyes with ACV£100 ml, ACA£25o and ACD£2.1 mm should be considered at high risk for developing acute angle closure and can be considered for prophylactic laser peripheral iridotomy (LPI).

Purpose: To determine the effect of recession and myectomy on inferior oblique overaction (IOOA).Method: This study was performed on 50 patients (82 eyes) scheduled for IOOA surgery who were randomly divided into two groups: recession (R) versus myectomy (M). A complete eye examination was performed before the operation. 10 was cut off at its inferior temporal region when using M procedure. In the other group (R) after disinsertion, the 10 muscle was sutured to 2mm lateral and 3.5 to 4mm posterior to the insertion of the inferior rectus. After at least 3 months, the same examinations were repeated. Successful surgery was defined as IOOA£+1.Results: Twenty-five men (50%) and 25 women with the mean age of 12.3±5.9 (range 3-32) years entered the study. The surgery was performed in 18 patients unilaterally and in 32 patients bilaterally. Both myectomy and recession methods were successful in reducing IOOA (PM<0.001, PR<0.001).The amount of IOOA reduction was 2.37 in the M group and 1.92 in the R group which was not significantly different (P=0.097, using Mann-Whitney test); however, ordinal logistic regression showed a difference (P=0.016). We found primary IOOA without superior oblique under action (SODA) in 28 eyes in the M group and in 32 eyes in the R group. Secondary IOOA with superior oblique underaction (SODA) was found in 14 eyes in the M and in 8 eyes in the R group, respectively. In patients with more initial 100A, the outcomes of both methods were better compared to patients with less initial overaction. There was no statistically significant difference in postoperative function of 10 between these two methods of surgery (P=0.051). Both methods resulted in equal improvements in SODA and V-pattern. Complications included new hypertropia (2%), new DVD (dissociated vertical deviation) (8%) and asymmetry (2%).Conclusion: Both recession and myectomy have significant weakening effect on IOOA. Myectomy results in more normal function of IOOA but IOOA is also higher with this method. Both methods are more effective if the initial overaction is higher.

Lamellar keratoplasty (LK) has been a well established technique of corneal transplantation. Recent improvements in surgical instruments have revolutionized the procedure introducing a new technique employing deeper corneal dissection. This review article describes the indications, techniques, outcomes and complications of deep anterior LK.

Purpose: To report the clinical, paraclinical and histopathologic features of eyelid mass lesions in a patient with tuberous sclerosis.Case report: A 14 year old boy with a slowly progressive right upper lid mass and history of seizures, mental retardation and multiple skin lesions on the face and body was referred to Labbafinejad Medical Center. Cortical tubers and subepandimal nodules were reported in neuroimaging and fibroadenoma with sebaceous hyperplasia were observed on histopathologic assessment. A diagnosis of tuberous sclerosis was made based on multiple major signs and the patient was referred to other subspecialities for comprehensive medical care. Conclusion: The ophthalmologist may be the first specialist to diagnose tuberous sclerosis because of associated ocular signs. Attention to systemic signs is necessary to establish a diagnosis.

Purpose: To report the clinical, confocal scan, and histopathologic features of bilateral Nocardia keratitis following photorefractive keratectomy (PRK).Case report: A 23-year-old girl underwent simultaneous bilateral PRK for myopia. On the third postoperative day, dense central infiltrates mainly involving the anterior stroma were noticed in both eyes.Clinical and confocal scan features were consistent with a diagnosis of Nocardia keratitis and topical amikacin eye drops 2% were started. Empirical antibiotic therapy was converted into specific therapy after confirming the definite diagnosis by clinical features and confocal scan. Due to poor response to medical therapy, lamellar keratectomy was performed in both eyes which shortened the treatment course.Histopathologic examination confirmed the initial diagnosis.Conclusion: Familiarity with the clinical and confocal scan features of Nocardia keratitis facilitates early diagnosis, proper management and hence a rapid clinical response.