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Photodynamic therapy (PDT) with verteporfin for age related macular degeneration (AMD) usually requires a course of treatment. The decision to re-treat is based on identifying leaks on a fundus fluorescein angiogram (FFA); however, leaks can be hard to distinguish from fluorescein staining, especially after several treatments. 1, 2 Optical coherence tomography (OCT) represents a fast and non-invasive examination technique that generates two dimensional sections of the posterior pole in vivo. 3- 5 Changes to the OCT findings following PDT have been presented but which features correlate most closely with the presence of leaks on an FFA have not been fully assessed. 6, 7, 8, 9, 10
We aimed to compare the appearance of the OCT with the presence or absence of leaks on FFA during the course of PDT follow up to see which OCT features best correlated with the presence of leaks and so give guidance to help re-treatment decisions.
MATERIALS AND METHODS
The data were collected retrospectively from a pool of patients who had all received initial PDT with verteporfin for a classic or predominantly classic subfoveal CNV secondary to AMD between July 2001 and October 2004, to allow at least 3 months of follow up. The greatest linear dimension (GLD) of the total lesion had to be <5400 μm. PDT was performed as standard in the TAP study. 1
From the series of 3 monthly follow up visits, one visit was randomly chosen for each patient from our collected database. The OCT and FFA from the same visit were analysed. Where bilateral treatment had been performed, one eye was randomly chosen for analysis. Random visits were chosen to reduce possible bias from knowledge of previous visits. In this study we did not assess the clinical findings or changes in vision as the features of the FFA and OCT were to be recorded objectively, without knowledge of the subjective changes. The investigators were masked to the treatment course, number of treatments, and whether treatment was given or not at that visit.
Stereo FFA was performed by an accredited ophthalmic photographer using the standard protocol of the Digital Angiography Reading Centre (DARC), Wisconsin, with a Zeiss Fundus Camera (FF450IR). The image capture software was Digital Healthcare (version 4.11.0.15). The presence of leaks was...