Journal of Ophthalmic and Vision Research
Volume:5 Issue: 3, Jul-Sep 2010

To estimate cure rate following graft rejection in bilateral corneal transplants in Iranian patients with keratoconus and to determine risk factors associated with rejection. In this retrospective study, data were compiled from records of patients who had undergone bilateral penetrating keratoplasty (PK) for keratoconus between 1988 and 2007. In order to estimate cure rate in patients with and without corneal vascularization, we adopted the cure rate frailty model with a Bayesian approach. Two hundred and thirty-eight eyes of 119 patients underwent bilateral corneal transplantion for keratoconus, of which 22.7% experienced graft rejections. Cure rates for patients with and without corneal vascularization were 41% and 79% respectively. Cure rate decreased 12% per decade of increase in recipient age. The 1, 5, and 10-year survival of corneal transplants without any graft rejection episodes were 82%, 74%, and 70% respectively. The most important risk factor predisposing to rejection in patients undergoing bilateral PK for keratoconus is corneal vascularization. Cure rate for patients without vascularization was high in this data set, indicating that penetrating keratoplasty in keratoconus patients without vascularization is an efficient and reliable procedure.

To assess the effect of ocular media opacity on retinal nerve fiber layer (RNFL) thickness measurements by optical coherence tomography (OCT). In this prospective, non-randomized clinical study, ocular examinations and OCT measurements were performed on 77 cataract patients, 80 laser refractive surgery patients and 90 patients whose signal strength on OCT was different on two consecutive measurements. None of the eyes had preexisting retinal or optic nerve pathology, including glaucoma. Cataracts were classified according to the Lens Opacity Classification System III (LOCS III). All eyes were scanned with the Stratus OCT using the Fast RNFL program before and three months after surgery. Internal fixation was used during scanning and all eyes underwent circular scans around the optic disc with a diameter of 3.4 mm. Average RNFL thickness, quadrant thickness and signal strength significantly increased after cataract surgery (P < 0.05). Cortical and posterior subcapsular cataracts, but not nuclear cataracts, had a significant influence on RNFL thickness measurements (P < 0.05). There was no significant difference between OCT parameters before and after laser refractive surgery. In eyes for which different signal strengths were observed, significantly larger RNFL thickness values were obtained on scans with higher signal strengths. OCT parameters are affected by ocular media opacity because of changes in signal strength; cortical cataracts have the most significant effect followed by posterior subcapsular opacities. Laser refractive procedures do not seem to affect OCT parameters significantly.

To evaluate the efficacy and safety of Ahmed Glaucoma Valve (AGV) implantation with adjunctive use of preserved amniotic membrane for surgical management of refractory glaucoma. Seven patients (5 female subjects) with refractory glaucoma were included in the study. An AGV (model FP7) was implanted in the usual manner and was covered with two layers of cryopreserved human amniotic membrane. Intraocular pressure (IOP) and number of glaucoma medications before and after surgery, and complications were evaluated. Mean duration of follow-up was 16.8±4.6 months. Mean preoperative IOP was 31.7±4.4 mmHg which was reduced to 17.7±6.1 mmHg at final follow-up (P = 0.01, Wilcoxon U test). Although the number of topical medications was also reduced (mean decrease of 0.85 drops), this decrease was not significant (P = 0.10, Wilcoxon U test). None of the eyes developed encapsulation after surgery; only one case was complicated by posterior migration of the implant resulting in failure. Glaucoma shunt surgery using the AGV with adjunctive amniotic membrane seems to be a safe and effective procedure which may reduce the risk of bleb encapsulation in refractory glaucomas.

To evaluate the effect of pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling for management of refractory diffuse diabetic macular edema (DME). In this prospective interventional case series, eyes with refractory diffuse DME unresponsive to macular photocoagulation and/or intravitreal bevacizumab, and best corrected visual acuity (BCVA)? 20/200 and? 20/60 underwent triamcinolone-assisted PPV with ILM peeling. Pre- and postoperative evaluations included a complete ophthalmologic examination, fluorescein angiography and optical coherence tomography (OCT). Main outcome measures were BCVA and central macular thickness (CMT). Twelve eyes of 12 patients with mean age of 59.6±3.9 (range, 55-68) years were operated and followed for a mean period of 4.9±1.0 (range, 4-6) months. Mean BCVA at final examination was 0.82±0.18 logMAR which was not significantly better than its preoperative value of 1.00±0.80 logMAR (P=0.959). Visual acuity improved by at least 2 lines in 3 eyes (25%), remained stable in 7 eyes (58%) and decreased by at least 2 lines in 2 eyes (17%). Mean CMT at final examination was 315±95 µm, which was significantly less than its preoperative value of 467±107 µm (P=0.004). Complications included vitreous hemorrhage in 2 and cataract progression in 5 eyes. PPV with ILM peeling for refractory diffuse DME seems to reduce macular thickness, but does not significantly improve visual acuity as observed after an intermediate-term follow up of about 6 months.

To evaluate the results of intravitreal expansile gas injection, with or without recombinant tissue plasminogen activator (rtPA), followed by intravitreal bevacizumab injection for treatment of submacular hemorrhage (SMH) secondary to neovascular age-related macular degeneration (AMD). In this interventional case series, 5 eyes of 5 patients with SMH secondary to choroidal neovascularization (CNV) due to neovascular AMD were treated with 0.3 cc intravitreal SF6 (and 50 µg of rtPA in two eyes), followed by face-down positioning; 24 hours later, 1.25 mg of bevacizumab was injected intravitreally. Main outcome measures included displacement of SMH and best corrected visual acuity (BCVA). Mean patient age was 75.6±9.2 (range, 60-83) years, mean duration of symptoms was 6.4±3.2 (range, 3-10) days, and mean number of bevacizumab injections was 1.8 (range, 1-3). Mean preoperative BCVA was 1.28±0.27 logMAR which improved significantly to 0.57±0.33 logMAR at 12 months (P=0.042). SMH displacement occurred in all eyes, and visual acuity improved and remained stable during the follow-up period of 12 months. Intravitreal expansile gas injection, with or without rtPA, followed by intravitreal bevacizumab injection, seems to be an effective modality for SMH displacement and treatment of the underlying CNV in neovascular AMD.

To compare the Cambridge contrast sensitivity (CS) test and visual evoked potentials (VEP) in detecting visual impairment in a population of visually symptomatic and asymptomatic patients affected by clinically definite multiple sclerosis (MS). Fifty patients (100 eyes) presenting with MS and 25 healthy subjects (50 eyes) with normal corrected visual acuity were included in this study. CS was determined using the Cambridge Low Contrast Grating test and VEP was obtained in all eyes. Findings were evaluated in two age strata of 10-29 and 30-49 years. Of the 42 eyes in the 10-29 year age group, CS was abnormal in 22 (52%), VEP was also abnormal in 22 (52%), but only 12 eyes (28%) had visual symptoms. Of the 58 eyes in the 30-49 year group, CS was abnormal in 7 (12%), VEP was abnormal in 34 (58%), while only 11 eyes were symptomatic. No single test could detect all of the abnormal eyes. The Cambridge Low Contrast Grating test is useful for detection of clinical and subclinical visual dysfunction especially in young patients with multiple sclerosis. Nevertheless, only a combination of the CS and VEP tests can detect most cases of visual dysfunction associated with MS.

Demyelinating optic neuritis is the most common cause of unilateral painful visual loss in the United States. Although patients presenting with demyelinating optic neuritis have favorable long-term visual prognosis, optic neuritis is the initial clinical manifestation of multiple sclerosis in 20% of patients. The Optic Neuritis Treatment Trial (ONTT) has helped stratify the risk of developing multiple sclerosis after the first episode of optic neuritis based on abnormal findings on brain MRI. The ONTT also demonstrated that while initial treatment of optic neuritis with intravenous corticosteroids followed by an oral taper accelerates visual recovery, its use does not improve long-term visual outcomes. Long-term treatment with immunomodulating agents such as interferons has been shown to improve clinical outcomes and neuroimaging abnormalities in multiple sclerosis; furthermore interferon use has been associated with decreased risk of subsequent multiple sclerosis in patients with an acute neurologic syndrome. However, several questions regarding the presentation, management, and implications of acute demyelinating optic neuritis remain unanswered.

To report the effectiveness of non-invasive management of congenital eversion of the eyelids, a rare condition associated with serious socio-psychological consequences. CASE REPORT: Three neonates with congenital eversion of the eyelids and secondary conjunctival chemosis and prolapse were managed with 5% hypertonic normal saline, lubricants, antibiotics, and padding. Complete eye opening was achieved by the 10th day of presentation and the condition resolved. Non-invasive management of congenital eyelid eversion was found to be effective with no need for surgical management. All health care workers should be informed that this condition is amenable to conservative treatment if started early, so that prompt referral for expert management can be offered.

To report a case of central serous chorioretinopathy after solar eclipse viewing. CASE REPORT: A middle-age man developed a sudden-onset unilateral scotoma after viewing a partial solar eclipse in Hong Kong. Fundus examination, fluorescein angiography, and optical coherence tomography showed features compatible with central serous chorioretinopathy. The patient was managed conservatively and reevaluated periodically. Serial optical coherence tomographic evaluations demonstrated an initial increase in the amount of subretinal fluid which spontaneously resolved 10 weeks after the onset of symptoms. This case demonstrates the possibility of development of central serous chorioretinopathy following solar eclipse viewing.

Endothelial keratoplasty (EK) is the most exciting recent development in corneal transplantation. It has experienced surprisingly rapid growth in a very short period of time. One of the indications for EK is pseudophakic bullous keratopathy. However, concomitant intraocular lens (IOL) exchange, if indicated, may prove challenging. Some surgeons routinely perform IOL exchange with a scleral-fixated posterior chamber IOL, together with Descemet''s stripping endothelial keratoplasty (DSEK); however, this combined procedure is time-consuming, difficult and fraught with complications. Another option is aphakic Artisan IOL fixation, but this is usually not acceptable because of the increased risk of endothelial cell loss and difficulty in filling the anterior chamber with the air bubble. Herein, we introduce a new technique for IOL exchange with an aphakic Artisan IOL fixated posterior to the iris, combined with DSEK. This surgical technique was designed to preserve anterior segment anatomic features as much as possible.