Late-onset visual decline following successful treatment of subfoveal choroidal neovascularisation with photodynamic therapy

One-year results of photodynamic therapy for small predominantly classic choroidal neovascular membranes secondary to age-related macular degeneration

PURPOSE

To determine the visual and angiographic outcomes of patients with small predominantly classic choroidal neovascular membranes (CNV) undergoing photodynamic therapy (PDT).

METHODS

The subjects were a cohort of patients with age-related predominantly classic CNV with lesion size of greatest linear diameter of 2000 microm or less treated with PDT. Lesion size and visual acuity were recorded at baseline and at 3-month intervals. Visual treatment failure was defined as either loss of at least 15 letters or visual acuity less than 35 letters on a modified Early Treatment Diabetic Retinopathy Study chart. Lesion treatment failure was defined as increase in greatest linear diameter (GLD) of at least 500 microm.

RESULTS

Twenty-five eyes of 25 patients were included. Visual treatment failure occurred in 16 and mean visual acuity dropped from 58 letters to 34 letters (p<0.0001). In 11 of these patients this occurred within the first 3 months. Lesion treatment failure occurred in 18 patients. Mean GLD increased from 1331 to 2935 microm (p<0.0001). Early growth of the lesion was associated with poor visual outcome with growth in GLD in the first 3 months of 310 microm in patients without eventual visual treatment failure and 1131 microm in patients with eventual visual failure (p=0.027).

CONCLUSIONS

Small predominantly classic lesions commonly cause visual deterioration if treated with PDT alone. In the first year over 50% may lose at least 15 letters or drop below 35 letters, with most visual loss occurring in the first 3 months. Visual loss is associated with early lesion growth.

Verteporfin

Photodynamic therapy (PDT) with verteporfin (Visudyne), a photosensitising protoporphyrin derivative, is used in the management of subfoveal choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD) or pathological myopia (PM). PDT with verteporfin over 1 and 2 years reduces the decline in visual acuity in patients with classic-containing subfoveal CNV secondary to AMD. Verteporfin is generally well tolerated by most patients. Verteporfin is also effective in patients with CNV secondary to PM, although data in this indication are limited and further controlled studies are required. Although verteporfin has shown efficacy in patients with occult AMD-related subfoveal CNV lesions in early trials, data are currently limited on its first-line use in this indication; fully published data from the Verteporfin In Occult (VIO) trial are therefore awaited with interest. Verteporfin should be considered as a first-line treatment in patients with predominantly classic subfoveal CNV secondary to AMD, and in patients with smaller minimally classic subfoveal CNV lesions. It may also be considered an option for the treatment of patients with occult AMD-related subfoveal CNV in whom visual acuity decreases or predominantly classic features develop over time.