Abstract
Purpose: :
To report on progression from early to late age-related macular degeneration (AMD) in a longitudinal study of outcomes following photodynamic therapy (PDT).
Methods: :
The VPDT cohort study is a register recording the functional and morphological outcomes in patients who received PDT for neovascular AMD between Sept 2004 and August 2008 with colour and angiographic outputs from both eyes submitted 3 monthly to NetwORC UK for systematic grading. Features that were graded included characteristics of the neovascular AMD lesion in the treated eye and severity of early AMD in the fellow eye if unaffected by late stage disease. The extent and severity of drusen and presence of pigmentary irregularities were combined to give an 8 step graded categorical severity scale. The database was interrogated to extract longitudinal information for the 12 month visit (min. 300 days) on disease severity progression in fellow eyes free of neovascular AMD at the first visit.
Results: :
Of the 8479 patients with a first visit recorded in the PDT database, 3776 had no evidence of late AMD in the fellow eye. We extracted data on 196 patients who fell into the latter category. In 168 of these, complete clinical and demographic data as well as AMD severity staging was available at both baseline and 12 months. By the 12 month visit, 6 of the 168 eyes had progressed to late AMD (4%). The mean age was 78.32 years (range 57-101 years). Regression analysis with conversion to AMD as the dependent variable and age, smoking history and stage at baseline as the independent variables showed that AMD severity staging at baseline was highly statistically significant (p<0.001). Smoking history was in the intuitively correct direction for significance (p=0.08) while the other variables were not entered into the model.
Conclusions: :
Our results are in accord with previous studies and show that the severity of early AMD change is important in determining progression rates at 12 months. These analyses will be extended to look at time points beyond 12 months for progression.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • imaging/image analysis: clinical