Abstract
Purpose: :
Selective–Retina–Therapy (SRT) is currently investigated in a prospective, clinical trial for patients with branch retinal vein occlusion (BRVO) with visual acuity (VA) compromising macular edema. In comparison to conventional Argon laser treatment, SRT uses a train of µs laser pulses and selectively damages RPE–cells while protecting retinal structures. This clinical trial was designed to evaluate the visual and morphologic outcome of patients with BRVO treated with SRT.
Methods: :
8 eyes of 8 patients with BRVO with VA compromising macular edema were recruited into the study. Standardized VA assessment using ETDRS charts, fundus photography, fluorescein angiography (FA) graded by 2 independent observers and optical coherence tomography (Zeiss OCT III) were performed. Patients were treated with SRT focally using a frequency doubled Q–switched Nd:YLF laser (527nm). Each laser exposition contains a train of 30 pulses, each with a duration of 1,7 µs, at a repetition rate of 100 Hz. Follow–up examinations were performed after 3 and 6 months
Results: :
The SRT laser lesions were not visible ophthalmoscopically during treatment, but were detectable by FA. In OCT average foveal retinal thickness remained unchanged (baseline 328±119 µm; 6 months 310±135 µm). Moreover the maximum retinal thickness in the treated edematous macula area decreased from 503±86 µm at baseline to 427±73 µm at 3 months but increased again to 6 months visit (512±127 µm). FA leakage decreased in 25%, but remained stable in 75% of patients after 6 months. VA results at 6 months showed that 25% of patients had an improvement of greater than 1 line, 62.5% demonstrated a stabilization of VA within ±1 line and 12.5 % had a reduction of greater than 1 line
Conclusions: :
SRT leads only temporarily to a reduction of edema as shown in OCT maximum retinal thickness. This result can be adressed to RPE effects. Foveal retinal thickness as well as VA were not significantly affected in our study. Treatment parameters should be re–assessed (e.g.re–treatments, laser pattern) to keep up early positive effects. However a larger number of patients with macular edema due to BRVO should be treated for optimal therapy assessment.
Keywords: vascular occlusion/vascular occlusive disease • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • laser