Contact lenses are another common solution for the correction of refractive visual problems. Advantages include more natural vision, no change in cosmetic appearance, improved visibility, more freedom in recreational activities, and better peripheral vision. On the other hand, contacts are high maintenance, may get lost, are less comfortable for patients with dry eyes, may cause visual aberrations (including halos and fluctuating vision), and always carry an increased risk of infection and possible corneal scarring. In higher altitudes many adults become intolerant of contact lenses over time because of dry climate and decreased oxygen in the air
There are so many types of contact lenses available today - soft, rigid, gas permeable, toric for astigmatism, etc. – to suit people with nearsightedness, farsightedness, or astigmatism, For people who are presbyopic and over thirty-five, contact lenses can be fit asymmetrically to obtain monovison for reading. Ophthalmologist and optometrists recommend not sleeping with any contact lens in because this increases the chance of corneal infection.
Refractive Surgical Procedures
Refractive surgical procedure intended to reduce a person's dependency on glasses or contact lenses. The most common refractive surgical procedures performed today are:
LASIK (Laser In-Situ Keratomileusis):
It is a surgical procedure intended to reduce a person's dependency on glasses or contact lenses. In this procedure a thin hinged flap of cornea (the cornea is the transparent, dome-shaped window covering the front of the eye) is created and lifted to one side in order to allow laser treatment to the deeper part of the cornea. The flap is then repositioned in its original position.
EpiLASIK ( Epithelial Laser-Assisted In-Situ Keratomileusis: EPI LASIK) – it is a procedure, which combines the advantages of PRK and LASIK, Epi lasik involves the use of a microkeratome, similar to LASIK, however only the superficial epithelial layer of cornea is separated as in PRK and this flap is replaced following the reshaping of the cornea using the Excimer Laser.
PRK ( Photorefractive Keratectomy ), which was the original kind and is still sometimes used. It involves gently scraping some surface cells off the cornea and then using a laser beam to re-shape it.
Refractive Surgery (LASIK) Procedure: