Light energy can be focused onto the retina to treat a variety of diseases. There are several different types of laser treatment that can be done easily and relatively painlessly in the office:
Focal Macular Laser
This type of laser is used to seal abnormal leaking blood vessels that cause macular edema (swelling) and thus vision loss. This is especially useful for edema due to diabetes and to branch retinal vein occlusions. This helps lessen the chance of further vision loss.
Panretinal Laser Photocoagulation
This is a higher energy laser treatment that is used to cause the regression of abnormal new blood vessels (neovascularization) that are common in proliferative diabetic retinopathy, retinal vein occlusions, retinal artery occlusions, and other diseases. This treatment is designed not to improve vision, but to lessen the chances of future complications of neovascularization such as vitreous hemorrhage, retinal detachment, and neovascular glaucoma.
Laser Retinopexy
This can be used to seal retinal tears and small retinal detachments. Over time, the laser causes an adhesion of the retina to the deeper layers of the eye wall, thus lowering the chances that the retinal defect will enlarge. This type of laser can also be used during pneumatic retinopexy or to supplement certain surgical procedures done in the operating room.
Focal Laser of Choroidal Neovascular Membranes (CNV)
This type of treatment involves the destruction of new abnormal blood vessels that grow underneath the retina in conditions like macular degeneration, optic disc drusen, ocular histoplasmosis, among others. Retreatment is often necessary if this strategy is employed.
Photodynamic Therapy (PDT) with Visudyne (Verteporfin)
PDT employs a photosensitizing drug (a drug that is “activated” when exposed to light) called Visudyne (verteporfin) that is injected into the patient’s arm and circulates to the abnormal blood vessels. The doctor then focuses an extremely low-energy red laser beam through the pupil of the eye onto the leaky new vessels (CNV), activating the drug, which destroys the abnormal vessels. The objective is to destroy the abnormal blood vessels while relatively preserving neighboring healthy blood vessels and tissue. This has been used in macular degeneration and other diseases that have CNV. It has also been used in certain vascular ocular tumors such as retinal capillary hemangiomas and cavernous hemangiomas of the choroid, and for the chronic form of central serous retinopathy.