Rose bengal is an effective photosensitizing agent which interacts with argon green light to induce photochemical thrombosis of irradiated vessels. We used focal, low energy irradiation to occlude retinal and choroidal vessels in both albino and pigmented rabbits. Immediately after intravenous injection of rose bengal at concentrations of 10 and 20 mg/kg, irradiation was performed via a slit lamp-delivered argon green laser (514.5 nm) with the aid of fundus contact lens. In 11 eyes, arteries were treated with 50-100 interrupted bursts of 75u spot size at 0.2 sec and 40-100 mW (9 <Re <34 KJ/cm²)' and veins were treated with 30-100 bursts of 100u spot size, 0.2 sec, 50-100 mW (5 <Re <19 KJ/cm²) which resulted in total closure of retinal vessels for 1-12 days and variable closure of the surrounding capillaris. Eight eyes were treated with continuous irradiation 2-5 minutes at 7.5-40 mW, 75u spot size (35 <Re <273 KJ/cm²) to arterioles and 2-3.5 minutes, 7.5-40 mW, 100u spot size (12 <Re <107 KJ/cm²) to venules. These eyes developed massive closure of retinal and choroidal vessels, serous elevation of the retina, and disc neovascularization. In eight eyes choroidal vessels were irradiated with 10-20 mW, 15-60 sec, 500u spot size (31 <Re <306 KJ/cm²), resulting in mild retinal edema at 24 hours and permanent closure of choroidal vessels. There was minimal damage to surrounding tissue. Control eyes in all three groups irradiated utilizing the same parameters, but without rose bengal, demonstrated no evidence of thermal injury.

Date Published: 11 September 1989
PDF: 5 pages
Proc. SPIE 1066, Laser Surgery: Advanced Characterization, Therapeutics, and Systems, (11 September 1989); doi: 10.1117/12.952023

Published in SPIE Proceedings Vol. 1066:
Laser Surgery: Advanced Characterization, Therapeutics, and Systems
Kazuhiko Atsumi M.D.; Norman R. Goldblatt; Stephen N. Joffe M.D., Editor(s)