LASER is an acronym for Light Amplification and Stimulated Emission of Radiation. Thus laser is highly condensed powerful focussed source of monochromatic light in which various waves are in phase. Its energy or power can be varied to a desirable extent. They have been used in werfares, astronomy, light shows, industries and medical field including eye.Varieties of lasers are available for use in eye for different purposes. At the same time laser is not a panacea for every eye disorder.

YAG LASER for cutting thickened after-Cataracts and making hole in glaucoma, Excimer laser for refractive surgeries, etc. some lasers coagulate the tissues, while others disrupt the tissues and still others can make very sharp microscopic cuts. Thus a according to the requirement, the laser is used. Argon Diode Lasers and used for diabetic retinopathy, vascular occlusions, Eales' disease and ARMD, etc., In all these disorders certain abnormal vessels from in retina which leak and damage the retina. Laser coagulates and destroys these leaky abnormal blood and prevent their further formation. Laser surgery just treats the manifestation of disease and primary cause of disease has to be tackled separately if known.

YAG LASER is used for after cataract Intraocular lens is normally implanted in a capsule. Capsule can be compared to a thin semipermeable membrane surrounding the boiled egg. Boiled egg white can be compared to a cataractous lens, which is removed leaving behind its thin capsule. This capsule sometimes becomes thick in later life (may be after months to years after cataract surgery) which is called an 'after-cataract' formation. This after cataract needs to be cut either by surgery or laser. Laser is preferable as no cut without actually opening the eye as is required for incisional surgery.

YAG LASER in also used in Glaucoma surgery for making a hole doing a Peripheral Iridectomy (PI), particularly in the Angle Closure Glaucoma.