Ray F. Gariano

Retinal angiogenesis in development and disease.

The retina has long been regarded as ‘an approachable part of the brain’ for investigating neurosensory processes. Cell biologists are now capitalizing on the accessibility of the retina to investigate important aspects of developmental angiogenesis, including how it relates to neuronal and glial development, morphogenesis, oxygen sensing and progenitor cells. Pathological angiogenesis also occurs in the retina and is a major feature of leading blinding diseases, particularly diabetic retinopathy. The retina and its clinical disorders have a pivotal role in angiogenesis research and provide model systems in which to investigate neurovascular relationships and angiogenic diseases.

Healing of Retinal Photocoagulation Lesions

PURPOSE To systematically assess the changes in retinal morphology during the healing of retinal photocoagulation lesions of various clinical grades. METHODS Rabbits were irradiated with a 532-nm Nd:YAG laser with a beam diameter of 330 microm at the retinal surface, a power of 175 mW, and pulse durations between 5 and 100 ms. Retinal lesions were clinically graded 1 minute after placement as invisible, barely visible, light, moderate, intense, very intense, and rupture and were assessed histologically at six time points from 1 hour to 4 months. RESULTS At all pulse durations, the width of the retinal lesions decreased over time. At clinical grades of light and more severe (pulse durations, 10-100 ms), retinal scarring stabilized at 1 month at approximately 35% of the initial lesion diameter. Lesions clinically categorized as barely visible and invisible (pulse durations of 7 and 5 ms) exhibited coagulation of the photoreceptor layer but did not result in permanent scarring. In these lesions, photoreceptors completely filled in the damaged areas by 4 months. CONCLUSIONS The decreasing width of the retinal damage zone suggests that photoreceptors migrating from unaffected areas fill in the gap in the photoreceptor layer. Laser photocoagulation parameters can be specified to avoid not only the inner retinal damage, but also permanent disorganization and scarring in the photoreceptor layer. These data may facilitate studies to determine those aspects of laser treatment necessary for beneficial clinical response and those that result in extraneous retinal damage.

Selective retinal therapy with microsecond exposures using a continuous line scanning laser.

Purpose: To evaluate the safety, selectivity, and healing of retinal lesions created using a continuous line scanning laser. Methods: A 532-nm Nd:YAG laser (PASCAL) with retinal beam diameters of 40 μm and 66 μm was applied to 60 eyes of 30 Dutch-belted rabbits. Retinal exposure duration varied from 15 μs to 60 μs. Lesions were acutely assessed by ophthalmoscopy and fluorescein angiography. Retinal pigment epithelial (RPE) flatmounts were evaluated with live-dead fluorescent assay. Histological analysis was performed at 7 time points from 1 hour to 2 months. Results: The ratios of the threshold of rupture and of ophthalmoscopic visibility to fluorescein angiography visibility (measures of safety and selectivity) increased with decreasing duration and beam diameter. Fluorescein angiography and live-dead fluorescent assay yielded similar thresholds of RPE damage. Above the ophthalmoscopic visibility threshold, histology showed focal RPE damage and photoreceptor loss at 1 day, without inner retinal effects. By 1 week, photoreceptor and RPE continuity was restored. By 1 month, photoreceptors appeared normal. Conclusion: Retinal therapy with a fast scanning continuous laser achieves selective targeting of the RPE and, at higher power, of the photoreceptors without permanent scarring or inner retinal damage. Continuous scanning laser can treat large retinal areas within standard eye fixation time.

Posterior scleritis in patients with systemic lupus erythematosus.

PURPOSE To describe three cases of posterior scleritis associated with systemic lupus erythematosus. METHODS Retrospective chart review including ophthalmic examination, fundus photography, optical coherence tomography, angiography, ultrasonography, and/or magnetic resonance imaging. RESULTS Three patients presented with blurred vision, red eye, and/or eye pain in one or both eyes. The diagnosis of posterior scleritis was confirmed in each patient using B-scan ultrasonography. One patient presented with giant nodular scleritis. In two patients, posterior scleritis was the presenting sign of systemic lupus erythematosus. Two patients received systemic corticosteroids together with noncorticosteroid immunosuppressive medications. One patient received topical and periocular injections of corticosteroids. All three patients showed prompt resolution of their posterior scleritis in response to treatment. CONCLUSION While uncommon, posterior scleritis may occur in patients with systemic lupus erythematosus and, in some instances, may be the presenting sign of the disease. Prompt diagnosis and treatment was associated with good visual outcomes in our patients.

Visual loss associated with accidental subretinal injection of triamcinolone acetonide.

PURPOSE To describe a complication of and possible retinal toxicity associated with sub-Tenon space injection of triamcinolone acetonide (TA). METHODS An interventional case report is presented. During attempted sub-Tenon space injection of TA suspension (40 mg/mL), ≈0.3 mL was inadvertently injected into the temporal subretinal space. Potential sequelae of subretinal TA were assessed with fundus photography and visual field testing. RESULTS Although subretinal TA resorbed quickly, a dense nasal visual field defect and retinal pigment epithelial changes corresponding to the area of initial subretinal TA deposition persisted for at least 18 months. CONCLUSION Subretinal TA may exert retinal and retinal pigment epithelial toxicity.

Selective retinal therapy with a continuous line scanning laser

This study evaluates the effects of exposure duration, beam diameter, and power on the safety, selectivity, and healing of retinal lesions created using a continuous line scanning laser. A 532 nm laser (PASCALTM) with retinal beam diameters of 40 and 66 μm was applied to 60 eyes of 30 Dutch-Belted rabbits. Retinal exposure duration varied from 15 to 60 μs. Lesions were acutely assessed by ophthalmoscopy and fluorescein angiography (FA). RPE flatmounts were evaluated with live-dead fluorescent assay (LD). Histological analysis was performed at 1 hour, 1 and 3 days, 1 and 2 weeks, and 1 and 2 months following laser treatment. Ophthalmoscopic visibility (OV) of the lesions corresponded to photoreceptor damage on histological analysis at 1 hour. In subvisible lesions, FA and LD yielded similar thresholds of RPE damage. The ratios of the threshold of rupture and of OV to FA visibility (measures of safety and selectivity) increased with decreasing duration and beam diameter. Above the threshold of OV, histology showed focal RPE damage and photoreceptor loss at one day without inner retinal effects. By one week, continuity of photoreceptor and RPE layers was restored. By 1 month, photoreceptors appeared normal while hypertrophy and hyperpigmentation of the RPE persisted. Retinal therapy with a fast scanning continuous laser achieves selective targeting of the RPE and, at higher power, of the photoreceptors. The damage zone in the photoreceptor layer is quickly filled-in, likely due to photoreceptor migration from adjacent zones. Continuous scanning laser can treat large retinal areas within standard eye fixation time.

Current Trends in Age-Related Macular Degeneration

Abstract Age-related macular degeneration is the leading cause of irreversible blindness in older persons of the developed world. Addressing treatable risk factors reduces the incidence and progression of this condition. Recent advances in understanding and treating macular degeneration have dramatically improved the visual prognosis.