Refractive Surgery is a procedure that restores near, intermediate, and far vision with an implantable lens.

If you have a refractive error, such as nearsightedness (myopia), farsightedness (hyperopia), astigmatism or presbyopia, refractive surgery is a method for correcting or improving your vision. There are various surgical procedures for correcting or adjusting your eye’s focusing ability by reshaping the cornea, or clear, round dome at the front of your eye. Other procedures involve implanting a lens inside your eye. The most widely performed type of refractive surgery is LASIK (laser-assisted in situ keratomileuses), where a laser is used to reshape the cornea.

Good vision depends on how well your cornea and lens focus light rays on the retina. Light rays must bend (refract) to focus on the retina. The retina is the light-sensitive nerve layer that lines the back of the eye. It creates impulses from the light rays that are sent through the optic nerve to the brain.

Refractive errors are vision problems caused by a cornea that is not shaped perfectly. The cornea is the clear part at the front of the eye. It bends and focuses light waves. Refractive errors cause light from an object not to be focused on the retina. This causes a blurred image. Refractive errors can occur in otherwise healthy eyes.

There are 4 types of refractive errors:

• Nearsightedness (myopia) Close objects appear sharp. But things in the distance are blurred. The eye is longer than normal from front to back. Or the cornea is curved too much. Images focus in front of the retina instead of on it.

• Farsightedness (hyperopia) You can see distant objects clearly. But objects up close are blurred. The eye is shorter than normal. Or the cornea is too flat. Images focus behind the retina.

• Astigmatism Objects are blurred at any distance. The cornea, lens, or both are shaped so that images aren’t focused sharply on the retina.

• Presbyopia This is also known as ageing eye. The eye loses its ability to change focus because of the natural ageing process. This often occurs between ages 40 and 50. Refractive surgery can’t correct this problem. Surgery can make distance vision clearer. But it may make near vision worse.

Types of surgery to correct refractive errors include:

• LASIK (laser in-situ keratomileusis)
• Photorefractive keratectomy (PRK)
• Radial keratotomy (RK)
• Astigmatic keratotomy (AK)
• Automated lamellar keratoplasty (ALK)
• Laser thermal keratoplasty (LTK)
• Conductive keratoplasty (CK)
• Intracorneal ring (Intacs)