Abstract
Purpose: :
To evaluate the short-term progression of neovascular age-related macular degeneration (AMD).
Methods: :
65 patients suffering from subfoveal CNV secondary to neovascular AMD were examined for inclusio into multicenter trials and observed until treatment initiation (baseline). Time intervals between screening and baseline varied from 2 to 110 days. Best Corrected Visual Acuity (BCVA) using EDTRS-charts, Cirrus HD-OCT and fluorescein angiography (FA) were obtained and changes of BCVA, retinal thickness and lesion size were compared according to lesion type over time.
Results: :
BCVA: Neither Type I lesions (=classic and predominantly classic CNV), nor Type II lesions (= minimal classic and occult CNV) showed significant deterioration of the BCVA letter score over time.HD-OCT: Differences of average thickness measurements and also of retinal volume in Type I lesions showed a limited, non-signifcant progression: retinal average thickness increased by 4,78±0,94µm and retinal volume increased by 0,11±0,03mm³. There was no measurable progression of HD-OCT parameters in Type II lesions.FA: The mean leakage size at 10 minutes after dye injection differed significantly, both in the pooled sample (Type I and Type II) and also if analysed separately. Considering the pooled sample, there was an increase from 5,50±0,62µm² at screening to 7,60±0,86µm² at baseline (p<0,00001). Type I lesions enlarged from 4,65±0,90µm² to 7,83±1,62µm² (p<0,007), while Type II lesions only progressed from 6,08±0,85µm² at screening to 7,45±0,96µm² at baseline (p<0,00001). The mean increase of leakage size per day in the pooled sample was 0,60±0,02µm², p<0,04. In a separate analysis, Type I showed a daily growth of 0,67±0,08µm² (p<0,02) while Type II lesion growth was markedly slower at 0,06±0,008µm² per day(p<0,000001).
Conclusions: :
FA seems to be more sensitive to the dynamic of CNV size over time. The progression of Type I lesions is 10 times faster than Type II lesions. Standard HD-OCT parameters offer only limited sensitivity to observe short-term progression in subfoveal CNV. BCVA did not show significant deterioration over the observed time interval, which might be attributed to a learning effect.
Keywords: choroid: neovascularization • imaging/image analysis: clinical • visual acuity