What Are Refractive Errors?

For us to see, light rays must be focused onto the retina, the nerve layer that lines the back of the eye. The retina receives the image formed by these light rays and sends the "image" to the brain through the optic nerve. The cornea and the lens form the focusing mechanism of the eye and are responsible for focusing a clear image onto the retina. Refractive errors occur when the focusing mechanism is not able to project a sharp image onto the retina.

What Are Types Of Refractive Errors?

Refractive errors can be classified into

myopia, hyperopia, astigmatism presbyopia.

What Is Myopia?

For people with myopia, or shortsightedness, their eyeball is longer and light rays are focussed in front of the retina. Close objects look clear but distant objects are blurred. High degrees of myopia predispose an eye to increased risk of cataract, glaucoma and retinal abnormalities. It is therefore important for highly myopic eyes to have regular eye examination by an eye doctor to detect abnormal changes in the eye.

What Is Hyperopia?

For people with hyperopia, or farsightedness, their eyeball is shorter and images are focussed behind the retina. Distant objects are clear while near objects are blurred.

What Is Astigmatism

The cornea is the transparent "window" of the eye. A normal cornea with no astigmatism has equal curvature in all directions. An astigmatic eye has unequal curvatures of the cornea. Astigmatism can distort or blur vision for both near and far objects. You can have astigmatism in combination with myopia or hyperopia.

What Is Presbyopia?

After the age of about 40, the focusing mechanism of the eye becomes increasingly inefficient. For people with presbyopia, or old age vision, objects close up appear blurred unless assisted by "reading glasses".

How Are Refractive Errors Corrected?

There are several means of correcting refractive errors. They all work by altering or assisting the focusing mechanism of the eye to focus a sharp image onto the retina.

Spectacles

Spectacles are the cheapest, safest and easiest method to correct refractive errors. They can be prescribed to correct most refractive errors satisfactorily. .

Contact Lenses

There are now a variety of contact lenses available that can correct all refractive errors. The type that is best suited for you depends on your eye, the refractive error and your lifestyle. You may discuss these options with your eye doctor

Refractive Surgery

Refractive surgery is a term referring to surgical procedures to reduce or correct refractive errors of an eye. The most common procedures in Singapore are laser procedures that include Photorefractive Keratectomy (PRK) and Laser-In-Situ Keratomileusis (LASIK).

What Is The Best Method To Correct Refractive Errors?

The choice of correction of refractive error varies from individual to individual. Factors affecting this choice include the severity and type of refractive error, patients' requirements, lifestyle and occupation. Your eye doctor will be able to advise you accordingly.

* This is a general guide. If in doubt, please consult your doctor.