Journal of Ophthalmic and Vision Research
Volume:5 Issue: 1, Jan-Mar 2010

To evaluate the correlation between refractive error and higher-order aberrations (HOAs) in patients with myopic astigmatism. HOAs were measured using the Zywave II aberrometer over a 6 mm pupil. Correlations between HOAs and myopia, astigmatism, and age were analyzed. One hundred and twenty-six eyes of 63 subjects with mean age of 26.4±5.9 years were studied. Mean spherical equivalent refractive error and refractive astigmatism were -4.94±1.63 D and 0.96±1.06 D, respectively. The most common higher-order aberration was primary horizontal trefoil with mean value of 0.069±0.152? m followed by spherical aberration (-0.064±0.130? m) and primary vertical coma (-0.038±0.148? m). As the order of aberration increased from third to fifth, its contribution to total HOA decreased: 53.9% for third order, 31.9% for fourth order, and 14.2% for fifth order aberrations. Significant correlations were observed between spherical equivalent refractive error and primary horizontal coma (R=0.231, P=0.022), and root mean square (RMS) of spherical aberration (R=0.213, P=0.031); between astigmatism and RMS of total HOA (R=0.251, P=0.032), RMS of fourth order aberration (R=0.35, P < 0.001), and primary horizontal coma (R=0.314, P=0.004). Spherical aberration (R=0.214, P=0.034) and secondary vertical coma (R=0.203, P=0.031) significantly increased with age. Primary horizontal trefoil, spherical aberration and primary vertical coma are the predominant higher-order aberrations in eyes with myopic astigmatism.

To report the long-term results of intravitreal bevacizumab (Avastin) therapy for choroidal neovascularization (CNV) secondary to non-age-related macular degeneration (non-AMD). This prospective interventional case series was conducted on patients with non-AMD CNV. All patients received 1.25 mg intravitreal bevacizumab and were followed for at least 18 weeks. Indications for retreatment were decreased visual acuity or recurrence of subretinal fluid or hemorrhage associated with leakage on fluorescein angiography. Primary outcome measures were changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT). Secondary outcome measures consisted of any adverse event related to the therapy. The study included 31 eyes of 28 patients with non-AMD CNV including idiopathic (n=11), due to myopia (n=7), angioid streaks (n=5), and other disorders (n=8). Mean initial BCVA was 20/100 which improved to 20/60 at 6 weeks; 20/40 at 12, 18, 24, and 36 weeks; and 20/30 at 54 weeks. Serial optical coherence tomography measurements showed mean CMT of 288 µm at baseline, which was decreased to 209 µm at last visit (P=0.95). There was no correlation between the underlying disease and changes in BCVA during the follow-up period. Intravitreal bevacizumab significantly improved visual acuity in eyes with non-AMD CNV due to various etiologies.

To present a novel automated method for tracking and detection of retinal blood vessels in fundus images. For every pixel in retinal images, a feature vector was computed utilizing multiscale analysis based on Gabor filters. To classify the pixels based on their extracted features as vascular or non-vascular, various classifiers including Quadratic Gaussian (QG), K-Nearest Neighbors (KNN), and Neural Networks (NN) were investigated. The accuracy of classifiers was evaluated using Receiver Operating Characteristic (ROC) curve analysis in addition to sensitivity and specificity measurements. We opted for an NN model due to its superior performance in classification of retinal pixels as vascular and non-vascular. The proposed method achieved an overall accuracy of 96.9%, sensitivity of 96.8%, and specificity of 97.3% for identification of retinal blood vessels using a dataset of 40 images. The area under the ROC curve reached a value of 0.967. Automated tracking and identification of retinal blood vessels based on Gabor filters and neural network classifiers seems highly successful. Through a comprehensive optimization process of operational parameters, our proposed scheme does not require any user intervention and has consistent performance for both normal and abnormal images.

To evaluate the clinical features, etiology and outcomes of treatment for superior oblique (SO) palsy over a 10-year period at Labbafinejad Medical Center. A complete ophthalmologic examination with particular attention to forced duction test (FDT) and tendon laxity was performed in all patients preoperatively. The palsy was divided into congenital and acquired types. Overall, 73 patients including 45 male (61.6%) and 28 female (38.4%) subjects with mean age of 19.7±11.7 (range, 1.5-62) years, were operated from 1997 to 2007. SO palsy was congenital in 56 (76%) and acquired in 17 (24%) cases. The most common chief complaint was ocular deviation (52.1%). FDT was positive in only 7 (9.7%) cases. Other clinical findings included amblyopia (19.2%), head tilt (13.7%), chin down position (4.1%), facial asymmetry (6.8%) and tendon laxity (2.7%). Mean preoperative vertical deviation was 16.1 prism diopters (PD) which was decreased to 1.9 PD postoperatively. Mean exotropia and esotropia were 15 and 13.9 PD respectively before the operation and both decreased to 1.5 PD of horizontal deviation postoperatively. The most common type of SO palsy based on Knapp’s classification was type 3 (42.5%). The most common operated muscle was the inferior oblique (83.6%) and the most common type of operation was inferior oblique myectomy (83.6%). The success rate for initial surgery was 84% and was increased to 96% with a second intervention. The most common form of SO palsy requiring surgical intervention was congenital which occurred most frequently in young males. Most cases of SO palsy can be successfully treated with a single surgical procedure.

To report the outcomes of surgical and non-surgical treatment in sixth nerve paresis and palsy. This retrospective study was performed on hospital records of 33 consecutive patients (37 eyes) with sixth nerve dysfunction who were referred to Labbafinejad Medical Center from September 1996 to September 2006, and underwent surgical procedures or botulinum toxin injection. Patients were divided into three groups: group A had muscle surgery without transposition, group B underwent transposition procedures and group C received Botulinum toxin injection. Overall, 33 patients including 19 male and 14 female subjects with mean age of 20.4±17.2 years (range, 6 months to 66 years) were studied. Eye deviation improved from 50.3±16.8 to 6.0±9.8 prism diopters (PD) after the first operation and to 2.5±5.0 PD after the second operation in group A, from 56.9±24.3 to 5.5±16.0 PD after the first procedure and to almost zero following the second in group B, and from 44.3±10.5 to 15.0±20.0 PD 6 months following botulinum toxin injection in group C. Head posture and limitation of motility also improved significantly in all three groups. The overall rate of reoperations was 21%. Various procedures are effective for treatment of sixth nerve dysfunction; all improve ocular deviation, head turn and abduction deficit. The rate of reoperation is not high when treatment is appropriately selected according to clinical condition.

To describe a series of patients with Non-Hodgkin''s lymphoma (NHL) and concomitant eyelid carcinoma. In this non-comparative interventional case series, we retrospectively reviewed the medical records of 5 patients with NHL who developed eyelid carcinoma. The patients included one female and four male subjects. Systemic lymphoma had been diagnosed 1 to 72 months prior to development of the eyelid carcinoma. The lesions were basal cell carcinoma in three, and squamous cell carcinoma in two cases. The lymphoma was advanced (stage III or IV) in all patients. Four patients underwent surgical excision of the carcinoma and one patient was awaiting surgical treatment after completing systemic chemotherapy. Three subjects had high-grade carcinomas. Two patients had perineural invasion; one received adjuvant radiotherapy postoperatively but the other did not due to receiving systemic chemotherapy for recurrent NHL. Systemic lymphoma may be associated with aggressive eyelid carcinomas. Perineural invasion is frequently encountered in this situation and should be treated with adjuvant radiation therapy to decrease the likelihood of local recurrence.

The vitreoretinal interface is involved in a wide range of vitreoretinal disorders and separation of the posterior vitreous face from the retinal surface is an essential part of vitrectomy surgeries. A diverse range of enzymatic and non-enzymatic agents are being studied as an adjunct before or during vitrectomy to facilitate the induction of posterior vitreous detachment. There is a significant body of knowledge in the literature about different vitreolytic agents under investigation for a variety of pathologies involving the vitreoretinal interface which will be summarized in this review.

To report a case of Wolfram syndrome characterized by early onset diabetes mellitus and progressive optic atrophy. CASE REPORT: A 20-year-old male patient with diabetes mellitus type I presented with best corrected visual acuity of 1/10 in both eyes with correction of -0.25+1.50@55 and -0.25+1.50@131 in his right and left eyes, respectively. Bilateral optic atrophy was evident on fundus examination. The patient also had diabetes insipidus, neurosensory deafness, neurogenic bladder, polyuria and extra-residual voiding indicating atony of the urinary tract, combined with delayed sexual maturity. One should consider Wolfram syndrome in patients with juvenile onset diabetes mellitus and hearing loss. Ophthalmological examination may disclose optic atrophy; urologic examinations are vital in such patients.

To report a case of central retinal artery occlusion (CRAO) in a patient with metabolic syndrome X. CASE REPORT: A 64 year-old-man presented with abrupt, painless, and severe loss of vision in his left eye. Indirect ophthalmoscopy disclosed signs compatible with CRAO and laboratory investigations revealed erythrocyte sedimentation rate of 74 mm/h, C-reactive protein (CRP) level of 21 mg/l, hyperglycemia, hyperuricemia, hypertriglyceridemia and hypercholesterolemia. Fluorescein angiography and immunological studies excluded other systemic disorders. The patient met the full criteria of the National Cholesterol Education Program for metabolic syndrome X. In addition to different vascular complications such as stroke, and cardiovascular disease, metabolic syndrome X may be associated with retinal vascular occlusions.

Foreign bodies may drop during removal from the posterior segment and result in foveal damage. Due to high specific gravity and viscosity, ophthalmic viscosurgical devices (OVDs) can dampen and redirect the force of the dropping foreign body and therefore protect the fovea. Herein we describe our technique of foveal protection with OVDs and briefly demonstrate the results in five eyes with large posterior segment foreign bodies.