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Proceedings Paper

Selective retinal therapy with a continuous line scanning laser
Author(s): Yannis M. Paulus; ATul Jain; Ray F. Gariano; Hiroyuki Nomoto; Georg Schuele; Christopher Sramek; Resmi Charalel; Daniel Palanker
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Paper Abstract

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.

Paper Details

Date Published: 2 March 2010
PDF: 11 pages
Proc. SPIE 7550, Ophthalmic Technologies XX, 75500W (2 March 2010); doi: 10.1117/12.840574
Show Author Affiliations
Yannis M. Paulus, Stanford Univ. School of Medicine (United States)
ATul Jain, Stanford Univ. School of Medicine (United States)
Ray F. Gariano, Stanford Univ. School of Medicine (United States)
Hiroyuki Nomoto, Stanford Univ. School of Medicine (United States)
Georg Schuele, OptiMedica Corp. (United States)
Christopher Sramek, Stanford Univ. (United States)
Resmi Charalel, Stanford Univ. School of Medicine (United States)
Daniel Palanker, Stanford Univ. School of Medicine (United States)
Stanford Univ. (United States)


Published in SPIE Proceedings Vol. 7550:
Ophthalmic Technologies XX
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

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