Treatment parameters for selective occlusion of experimental corneal neovascularization by photodynamic therapy using a water soluble photosensitizer, ATX-S10(Na)

Time dependent change of an accumulation of an amphiphilic photosensitizer, ATX-S10(Na) on rabbit corneal neovascularization (CoNV) was evaluated by a ngiography using ATX-S10(Na) as a fluorescent dye on three rabbits. The ang iography showed that the dye accumulated on CoNV 3-5 hr after dye injection when the dye in the iris was minimum. The results suggested 3-5 hr after m ight be the optimal time to start photodynamic therapy (PDT) to occlude CoN V selectively without damage to the surrounding normal tissue such as the i ris. Then the optimal treatment parameters in PDT using ATX-S10(Na) for sel ective occlusion of the CoNV were investigated on rabbit eyes. PDT was perf ormed with two different time intervals between dye injection and laser irr adiation of a diode laser (670 nm), different laser doses and three differe nt dye doses on 21 animals. PDT performed immediately after dye injection s electively occluded CoNV with laser irradiations from 30.6 to 38.2 J cm(-2) and a 2 mg kg(-1) dose of ATX-S10(Na), as well as with 15.3 J cm(-2) and a 6 mg kg(-1) dose. PDT performed 4 hr after dye injection with 107.0-152.8 J cm(-2) and a 6 mg kg(-1) dose, as well as with 38.2-53.5 J cm(-2) and a 1 2 mg kg(-1) dose was also effective. Although PDT performed either immediat ely or 4 hr after ATX-S10(Na) injection selectively occluded CoNV, the widt h of the optimal range of radiant exposures seemed wider in PDT performed 4 hr after dye injection. It is supposed that this result is associated with the difference of dye accumulation between in CoNV and in normal tissue as shown by the present angiographical Endings. (C) 2000 Academic Press.