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The methods of vision correction have been constantly advancing as new technology and innovation have become available. Aside from the standard prescription eyeglasses and contact lenses, there are several modern procedures to choose from. Vision starts when light enters the eye through the cornea, which is the clear covering of the front of the eye. The coloured portion of the eye is the iris which opens and closes to regulate the amount of light that passes through. The light rays then pass through the lens of the eye, which changes its shape to bend the light rays and focus them at the light sensitive back portion of the eye called the retina. The retina then converts the light into electrical impulses which then travel through the optic nerve eventually reaching the brain where images are produced. Poor eyesight is almost always caused by misshapen corneas. When the cornea has an irregular shape, the light does not focus properly causing blurry vision. The most common of these errors are short sightedness, long sightedness, astigmatism, and presbyopia. When one wants an alternative to eyeglasses and contact lenses, vision problems can be corrected through eye surgery. The most common vision correction method is LASIK or Laser Assisted In Situ Keratomileusis. This is a procedure that uses a precision laser to permanently reshape the cornea. In this vision correction procedure, a thin circular flap is made in the cornea. A precision laser with a cool light beam is then used to remove very tiny bits of tissue from the cornea. This allows the eye surgeon to reshape the cornea with extreme accuracy. The goal is to reshape the cornea so that it can properly focus light onto the retina. After this is done, the flap is then put back in place and the surgery is complete. It is a relatively painless procedure done under a local anaesthesia. In around 15 minutes, the surgery is completed. The procedure is suitable for the treatment of short sightedness, long sightedness, and astigmatism. Because there is minimal trauma, healing occurs rapidly and most patients enjoy improved vision almost immediately. PRK or photorefractive keratectomy is another type of vision correction surgery. This is the forerunner of the LASIK method, first performed in 1987 in Germany. This was the most common refractive surgical correction before LASIK was developed. The procedure uses an excimer laser to flatten the steep cornea in short sighted people, make a steeper cornea in long sighted people, and smooth the irregular cornea in those with astigmatism. An advantage of PRK over LASIK is that there is no corneal flap created, eliminating the risk of flap complications during and after the procedure. This is also an alternative when LASIK cannot be done safely as in cases of corneas that are too thin, making it very difficult to make a corneal flap. Visual results are reportedly comparable to LASIK although healing is faster in LASIK with less post operative discomfort. LASEK or Laser Assisted Sub-Epithelial Keratomileusis is a newer eye surgery method. It combines the benefits of LASIK and PRK. LASEK is a better choice for people with less corneal tissue or corneas that are too flat, thereby not ideal candidates for LASIK procedure. In this method, a flap is created but is extremely thin and involves only the outer layer of the cornea. This is and then loosened using a solution of 20% alcohol. There is lesser risk of dry eye compared to LASIK. The outcome is similar to that produced by LASIK but healing and visual recovery takes longer after LASEK. On the other hand, epiLASIK is a variation where a part of the layer of the eye is removed. It also does not involve the creation of a corneal flap and is therefore apt for people with very thin corneas to be treated by LASIK. It also delivers excellent visual outcomes and is a safe procedure. However, there is longer healing and more discomfort associated with this method. Lens replacement surgery involves replacing the natural lens of the eye with an artificial lens. This is especially suitable for people with very high errors in vision such as extreme short sightedness or extreme long sightedness. Also called refractive lens exchange, RLE, clear lens extraction, or CLE, this is also suitable for older adults with cataracts. There are various causes of cataracts and the more common ones are ageing and injury changes in the lens tissue resulting to cloudiness in vision. Millions of people have benefited from the various vision correction methods available today. For anyone suffering from vision problems, modern eye correction procedures will help reduce or eliminate the need for glasses and contact lenses.
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vision correction, laser eye surgery, cataracts,
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