In most retinal laser treatments the therapeutic effect is initiated by a transient temperature increase at and around the retinal pigment epithelium (RPE). Especially in long exposure time treatments like Transpupillary Thermotherapy (TTT) choroidal perfusion has a strong influence on the realized temperature at the fundus. The fundus blood circulation and therefore the heat dissipation is influenced by the intraocular pressure (IOP), which is investigated in the study presented here. In order to reduce the choroidal perfusion, the IOP is increased by injection of physiological saline solution into the eye of anaesthetized rabbits. The fundus is irradiated with 3.64 W/cm² by means of a TTT-laser (λ = 810 nm) for t = 20 s causing a retinal temperature increase. Realtime temperature determination at the irradiated spot is achieved by a non invasive optoacoustic technique. Perfusion can be reduced by increasing IOP, which leads to different temperature increases when irradiating the retina. This should be considered for long time laser treatments.

Date Published: 13 July 2007
PDF: 7 pages
Proc. SPIE 6632, Therapeutic Laser Applications and Laser-Tissue Interactions III, 66321D (13 July 2007); doi: 10.1117/12.728222

Published in SPIE Proceedings Vol. 6632:
Therapeutic Laser Applications and Laser-Tissue Interactions III
Alfred Vogel, Editor(s)