Advances in ophthalmological photodynamic therapy

Photodynamic therapy is a new experimental therapeutic technique which is attracting increasing attention. Its biopharmacological basis of action is the specific interaction of a photosensitizing compound with the cellular elements of pathological lesions. The photosensitizer is thought to enter specifically into the pathologic cells, where it accumulates. The lesion is then irradiated with a sensitizing laser-beam of specific wave-length to activate the photosensitizer, which then becomes a generator of free oxygen radicals. These radicals destroy the sensitizer-harboring pathological cells. The advantage of specifically destroying pathological lesions without affecting surrounding normal tissue is obvious. Recently, many experimental studies have been conducted to test the usefulness of photodynamic therapy for ocular disorders, mainly advanced age-related macular degeneration and uveal melanoma. Results so far are encouraging.