Refractive Errors and Lasik Eye Surgery

Refractive Errors: Myopia, Hyperopia and Astigmatism

Clear vision in the normal eye is due to the light rays falling on the eye and passing through the cornea, pupil and lens and focusing the image on the retina. An error in the focusing of light by the eye is called as Refractive Error. If the optical power of the eye is too large, light produces image focus in front of the retina and this is called as Myopia (Short-sightedness). If the optical power of the eye is too small, light produces image focus behind the retina and this is called Hyperopia (Long-sightedness). When the cornea is shaped like the back of a spoon, light gets focused on more than one point and a blurred image is formed on the retina and this is known as Astigmatism (Cylindrical Error) and is often associated with short sight or long sight.

Treatment Options for Refractive Errors

There are different types of temporary and permanent treatment options for Refractive Errors. They are:

Temporary Options

• Spectacles

This is the most common temporary solution to correct refractive errors because of easy maintenance and low cost. The drawbacks of spectacles are obvious. They interfere with activities and change a person's appearance. Additionally, spectacles also reduce the peripheral vision.

• Contact Lenses

Contact lenses are a popular alternative to spectacles. They provide excellent peripheral vision and permit a wider range of activities than spectacles.
Contact lenses do not change a person's appearance. Problems with contact lenses include their recurrent costs, maintenance hassles and possibility of infection and intolerance due to sensitivities.

Permanent Options

There are various surgical options available for the permanent correction of these refractive errors. Your physician must choose the best treatment for your specific disorder. The person who wants to undergo a permanent treatment should be above 18 years and should have a stable spectacle power for over a year. S/he should not be suffering from other eye disorders like cataract, glaucoma, retinal disorders etc.
S/he should stop wearing soft contact lenses for 1 week & semi-soft contact lenses for at least 2 weeks prior to the procedure or measurements. Following are the permanent surgical treatments available for Refractive Errors:

Lasik (Laser in Situ Keratomileusis)

In Lasik, the corneal surface is reshaped using a laser beam. It corrects vision by altering refractive power of the eye by a calculated change in the corneal curvature. The image of the outside world is now focused sharply on the retina.

Wavefront Lasik or Customized Lasik

Wavefront Lasik or Customized Lasik is the result of a quantum leap in technology of sight restoration and enhancement. This Wavefront Guided Lasik is a giant step after conventional Lasik. Optical aberrations (imperfections) inherent in the eye may adversely affect the visual acuity and the optical performance of the eye. Conventional Lasik can only correct the spectacle power & not these subtle optical aberrations. With Wavefront Guided Lasik, it is now possible to reduce these aberrations and enhance vision much above the normal levels. Custom Vue (VISx star S4 from AMO) is the procedure available for customized Lasik.

Benefits of Lasik/Customized Lasik

• Simple to perform

• Predictable

• Stable

• Brief recovery time

• Minimal discomfort

• Minimal post-op care

• Low enhancement rate

• Very low infection rate

• Very low risk of scarring

The results with Lasik Eye Surgery are very stable and correction lasts for lifetime. In high powers, some residual power may remain or a slight regression may happen over a period of time. The chance of vision reducing complication is less than 1% and no sight threatening problems (loss of vision) are recorded. Some side effects like night glare rarely occur in very high powers. There is also a small possibility of regression especially in high powers. Infection is a remote possibility with every surgical procedure.

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