Refractive vision correction
What are refractive vision errors?
A vision is formed in the eye at the posterior most lining called the retina. This light is focussed with the help of the cornea. If the vision formation is affected due to the cornea, it is called a refractive vision error. Thus the defect in the focussing power related to cornea is refractive error.
The types of refractive errors are:
1. Myopia or Nearsightedness: In such patients the cornea is steep or the eye is longer, due to which the rays instead of falling at retina focus at front. Objects near to the eye are clear but far placed objects are blurred.
2. Hyperopia or Farsightedness: In such cases the cornea is flatter than usual or eye shorter than normal with the result that the image falls behind retina. Distant objects for such patients are clear and objects near are blurred.
3. Astigmatism : In it the cornea of the eye becomes more curved towards one direction or cone like. The vision is blurred for both far and near objects. This is termed as cylindrical refractive error and the light rays fail to reach one common focus in the eye.
Methods to treat Refractive errors
Refractive errors of the can be treated by both surgical and non surgical ways:
1. Glasses: The simplest, most common way to correct refractive error is through glasses. Glasses are the most preferred method. The process is simple where a visit to an eye expert can help a patient with the right eye prescription.
2. Contact lens: This method is a cosmetically advantaged option to glasses. The drawback is maintenance and keeping the lens clean. Also with its continuous use, there are risks of abrasion and infection to cornea. This is because the lens rests on the cornea of the eye.
3. Refractive surgeries: with the advancement in laser treatments, gradually laser refractive surgeries are gaining high popularity. There are various surgical intervention methodologies available in laser eye surgeries to correct refractive eye error. They improve or correct the focussing ability of light rays by the eyes, through reshaping of the cornea. Also for very thin cornea in which laser surgeries are not possible, intra ocular lens can be implanted.
Other than this for diseased cornea in which laser is not possible, rings are implanted in the eyes or crosslinking is done to maintain the shape of the cornea.
When does one need a surgical intervention for refractive vision error?
1. Some patient find the use of glasses very cumbersome and want to decrease their dependence on them. Similarly for contact lens user, the frequent eye infection, daily changing of the lens, cleaning of the lens pose an issue. To get rid of all these problems, patients are increasingly opting for refractive laser surgery for vision correction.
2. Patient with corneal disease have to wear soda glasses but still the vision keeps deteriorating. In such cases the cornea surgeon can provide you with an option of surgery called C3R or INTACS to maintain the corneal shape. Thus the cornea which keeps developing in a cone instead of being round is restricted from developing into a cone shaped structure and the vision is maintained at the best possible.