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2 March 2010 Selective retinal therapy with a continuous line scanning laser
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Proceedings Volume 7550, Ophthalmic Technologies XX; 75500W (2010)
Event: SPIE BiOS, 2010, San Francisco, California, United States
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.
© (2010) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yannis M. Paulus, ATul Jain, Ray F. Gariano, Hiroyuki Nomoto, Georg Schuele, Christopher Sramek, Resmi Charalel, and Daniel Palanker "Selective retinal therapy with a continuous line scanning laser", Proc. SPIE 7550, Ophthalmic Technologies XX, 75500W (2 March 2010);


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