Abstract
Abstract: :
Purpose: To assess the results of photodynamic therapy (PDT) with Visudyne on measures of retinal function and structure in patients with choroidal neovascular membrane (CNVM) secondary to age–related macular degeneration (ARMD). Methods: Five patients with CNVM with subretinal fluid secondary to ARMD were studied. Visual acuity, slit lamp examination, indirect ophthalmoscopy, fundus photographs, fluorescein angiography (FA), optical coherence tomography (OCT), Humphrey 10–2 visual fields, and multifocal electroretinograms (mfERG) were performed before, one week, and one and three months after treatment. The mfERG stimulus consisted of 103 scaled hexagons; the display subtended 50 degrees in diameter. Fixation stability was continuously monitored. First and second–order kernels were analyzed. The amplitude and implicit times of the 1st–order kernels were analyzed as described in Hood and Li (1997). The size of each 2nd order response within an epoch of 10–60 ms was analyzed using the root–mean–square (RMS) measure in VERIS software. SNRs were calculated for each subject for each response. Results: Pre–treatment OCT showed marked thickening with subretinal and intraretinal fluid accumulation. Post–treatment a decrease in retinal thickness and partial fluid re–absorption were noted. However for all 5 patients, there was little or no change in visual acuity, clinical examination or in the extent or severity of the sensitivity loss on the Humphrey 10–2 visual fields post–treatment. Pre–treatment, the mfERG showed markedly decreased response amplitudes in the central 10 degrees. The decreased responses affected a larger area than the CNVM, as indicated by FA. In addition, apparently normal retinal areas as documented by FA had significantly increased implicit times. These mfERG findings were unchanged 1 and 3 months post–treatment. Conclusions: The size of the CNVM on clinical examination and FA does not provide an accurate assessment of the area of retinal dysfunction. The post–treatment improvements observed on clinical examination were not seen on functional testing.
Keywords: electroretinography: clinical • imaging/image analysis: clinical • photodynamic therapy