Ophthalmology is the medical specialty dedicated to the study of the eye's structure and function, and to the diagnosis and treatment of diseases affecting them. In a normal eye, the cornea and the lens focus the light rays entering the eye to a single point close to the retina.

The retina, or the light sensitive tissue in the back of the eye, converts light impulses into nerve impulses. The nerve impulses move along the optic nerve to the brain, which interprets the impulses allowing these persons to "SEE". Three primary types refractive errors might occur. These are Myopia (near sightedness), Hyperopia (far sightedness) and Astigma.

Lasik is an acronym for LASer in-situ Keratomileusis, which simply means "to shape the cornea within using a laser." It corrects vision by reshaping the cornea (outer window of the eye) so that rays focus more precisely on the retina, thereby reducing or eliminating refractive errors.

It is done by using an instrument known as a microkeratome which cuts a thin flap of corneal tissue, then the laser is fired to remove predetermined amount o tissue& the corneal flap is placed back in its position without any stitch. This is done by use of topical anesthesia. As it is done under topical anesthesia, patient mobilization is early & there is no post-operative pain, less corneal scarring & haze.

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What is Cataract?
The human crystalline lens, is the primary focusing mechanism of the eye is clear. With age, it becomes cloudy and opaque, thereby hampering vision. Any opacity in the crystal tine lens is called cataract.

When to get surgery done?
Cataract should be removed when it begins to affect your daily activities. When glare or blur interfere while you are driving, it is time to consider having surgery. DO NOT WAIT FOR THE CATARACT TO GET MATURE for this may lead to complications and a more difficult surgery. CATARACT SURGERY CAN BE PERFORMED IN ANY SEASON.

Phacoemulsification
The phacoemulsification is the most modern method of removing a cataract lens. This surgery is done under topical anesthesia and no stitch is applied. So this is least traumatic to the eye.

The advantages of phacoemulsification are
.1 Early mobility of pt. early visual rehabilitation.
2. Stitch less surgery.
3. Final glasses can be prescribed after 2 weeks as compared to 10 10 weeks of conventional surgery.

Fluoresce in Angiography
F. A. is a technique of studying structure integrity & patency of blood vessels (especially of retinal & iris) using a dye fluorescien. This dye after absorbing the visible light gets activated & emits radiations which can be visualized by using special filters (cobalt-blue). F.A. not only helps in diagnosis but also helps to plan the treatment modalities for a particular patients.

Pre-requisites for Fluoresce in Angiography
1. Patient should be empty stomach.
2. Fully dilated pupil

Adverse effect of the dye in some patients.
1. Nausea & Vomiting
2. Allergic reactions
3. Vasovagal attack
4. Yellow/red discoloration of urine , skin & nails which passes off with times.

Diabetic Retinopathy
In diabetic retinopathy, Argon Laser is used mainly for treatment. For this only pupillary dilatation is needed. Argon laser is used to prevent the progression of the retinopathy, so that the sight of a person can be maintained.

What is PCO ?
After cataract surgery in some patients there is opacification of posterior of the human crystalline lens called PCO. This hampers vision of a patient. This can be treated with the use of Yag-Laser which destroys the metaplastic - epithelium of the lens, so that vision can be regained.