| |
Photodynamic therapy is a relatively newer technique of destroying the abnormal harmful new vessels that grow within and under the retina. These start behind the retina (actually in its central portion called macula, which is the main central area for vision) and gradually invade into it from behind. These vessels bleed under the macula and ultimately damage it by causing scarring and loss of central vision.
These abnormal vessels grow in certain diseases like age related macular degeneration and pathological myopia. PDT involves injected a special photosensitive dye into a vein of the forearm, from where it reaches these abnormal blood vessels under the macula. A special type of laser beam then activates this dye which ultimately damages these abnormal vessels without affecting the overlying macula (central retina). Thus unlike conventional retinal laser, it preserves the overlying retina which other wise also gets burnt during conventional laser treatment. PDT can be used for selected cases of abnormal subretinal new blood vessels. At the present time cost is a limiting factor in this treatment modality.
There are no "immediate" gains of doing PDT as it is mainly preventive treatment, as long term visual acuity and contrast sensitivity (qualitative aspects of vision) are better retained by undergoing the treatment. PDT may have to be repeated as the prime cause for exciting new blood vessel formation is not known till now. |
|
