Methodical Concepts of Treatment and Evaluation of Rubeosis Iridis with Photodynamic Therapy with Verteporfin
Purpose: To present results of a monocentre, open-label, intra-individual controlled, pilot phase I/II, dose-finding study that was initiated to determine light dose parameters for photodynamic therapy (PDT) with Verteporfin in the setting of occlusion of neovascularisation (NV) of the iris secondary to ischemic retinopathy in patients who did not benefit from panretinal laser photocoagulation and who might develop a neovascular glaucoma (NVG).
Methods: Treatment parameters for a single application of PDT with Verteporfin were chosen based on drug- and light-dose regimen tested for choroidal NV and on results of animal studies. Two opposite quadrants were treated with two different light doses, escalating from 12.5 and 25 J/cm2 up to a light dose of 50 and 75 J/cm2. Depending on the angiographic effect on the vessels, the next higher light doses were applied to the next group of 3 patients. The remaining two iris quadrants were not exposed to light and considered as intra-individual control. Primary outcome was defined as change in leakage from iridal neovascularisation on iris fluorescein angiography (FLA) measured by a global score and by a semi-quantitative planimetric analysis programme (EPCO). Secondary efficacy and safety variables were changes in anterior chamber flare, iris stroma-structure assessed by colour photography, IOP and visual acuity.
Preliminary results: Six out of a maximum of 48 planned patients have been included so far. At Week 1, a reduction of leakage from iridal neovascularisation on the iris FLA was seen in one patient at a light dose of 50 J/cm2. Complete absence of leakage occurred at a light dose of 75 J/cm2, in two patients. The safety variables did not show significant changes.
Conclusion: PDT with verteporfin appears to occlude NV of the iris secondary to ischemic retinopathy. Whether this vessel occlusion will have an impact on the progression of rubeosis or NVG will be the subject of further investigation.