This text is designed to provide clinicians with an understanding of the basic physics of PDT and the rationale and techniques of PDT in ophthalmology and especially in age-related macular degeneration. The different photosensitizers, lasers, and possible future use of this new therapeutic modality for other intraocular pathologies are also discussed. This text offers a step-by-step, detailed approach to the use of PDT, picking up where the scientific journal articles leave off.