Investigation of selective retina treatment (SRT) by means of 8 ns laser pulses in a rabbit model.

摘要: Background: It has been shown that selective retina treatment (SRT) using a train of 1.7 microseconds laser pulses allows damage the retinal pigment epithelium (RPE) while sparing adjacent photoreceptors and thus avoiding scotoma. was purpose this work to investigate SRT effects with Q-switched only 8 nanoseconds in duration by evaluating angiographic ophthalmoscopic thresholds range histology rabbit model. Materials Methods: A flash lamp pumped frequency doubled (532 nm) Nd:YAG pulse used. In total 210 lesions, each calculated be 102 mm diameter on retina, were applied through slit onto fundus six eyes Chinchilla Bastard rabbits. The rabbits irradiated increasing energies single 10 at Hz. After photography angiography performed determine (ED50-probability RPE cell neurosensory damage) as well safety between both (ratio ED86 vs. ED14). Selected taken for repetitive lesions after treatment. Results: Angiographic ED50-thresholds decreased number pulses. For application ED50 determined 365 144 mJ/cm 2 , respectively. Regarding 266 72 found. No hemorrhages or disruptions observed sets parameters. therapeutic window threshold revealed factor 3.1 2.3 irradiation. respectively had 0.8 (single pulses) (10 pulses). Histologic examination radiant exposures within window—292 213 respectively—revealed damaged RPE, intact Bruch’s membrane choriocapillaries. Photoreceptors partly spared but also various extents. Conclusions: Short can without hemorrhage disruption. Selective affecting rarely achieved due small range. Thus, so far microsecond seems favorable compared nanosecond order prevent unintentional photoreceptor damage. Lasers Surg. Med. 40:20–27, 2008. 2008 Wiley-Liss, Inc.