Several different types of lasers are used in ophthalmology. Retinal lasers use thermal energy (heat) to destroy tissue, form scar tissue, and stimulate parts of the retina. Lasers pass through the clear parts of the eye and are focused on the retina. No incisions are needed to introduce the laser into the eye.
This means there is a very low risk of infection from the laser. This also means that there needs to be a clear view to the retina. If there is a corneal problem, lens problem (cataract), or opacity in front of the retina, laser may not be possible. A contact lens is usually used to focus the laser on the retina. This lens is removed after the laser is performed.
Lasers may be needed to destroy tissue like abnormal growths on or in the retina. These growths can be abnormal blood vessels as in diabetic retinopathy and macular degeneration. They can also be abnormal growths of tissue like tumors or inflammatory lesions. The laser will cauterize the abnormal blood vessels. The laser can destroy the tumor or other lesions to stop the growth or cause regression. Occasionally, a retinal condition has gotten so severe as in advanced diabetic retinopathy, that some peripheral retina must be destroyed to save more important central retina.
Lasers can also be used to form scar tissue on the retina. This scar tissue can form a “glue” between the retina and the back wall of the eye. This scar can be used to treat a retinal tear and prevent a retinal detachment, repair a retinal detachment or barricade a retinal problem so it does not extend.
A laser can also be applied to the retina in such a way that it does not destroy it, but rather stimulates parts of it to function better. This is done largely in cases where there is retinal edema or swelling because the natural retinal “pump” is not as effective as it should be. Once this pump is stimulated, the retinal edema may be removed. This is helpful in a variety of conditions like diabetic edema, strokes of the eye, swelling after cataract surgery, and swelling due to inflammation in the body.
Another type of laser is used to treat new blood vessels growing in age related macular degeneration. This laser is not commonly used now, because other treatments have been more effective. However, it is still used in some cases.
The laser is used to activate a medicine that is introduced into the body by infusion through a vein. This medicine collects only in the abnormal vessels and when it is activated by the laser, destroys just the abnormal vessels and minimizes damage to healthy retina. Because the medicine has to be infused over a set amount of time, this laser is often not done in the office, but an infusion center instead.
Your retinal specialist can describe in detail what laser is indicated for your condition and what to expect afterwards.