Vision Problems and Range of Correction
When we look at something, the cornea of the eye focuses, or refracts, the light coming into the eye onto the retina. In a normal eye, one that does not require correction, the light rays come to a sharp point on the retina. If the cornea is misshapen or has an irregular curvature, the light going to the retina does not meet the retina properly, therefore objects appear blurry.
The result of the cornea failing to focus light correctly on the retina is a refractive error, which shows up as one or more of three vision problems:
- Myopia, or nearsightedness, causes close objects to be seen clearly, but objects farther away to appear blurred.
- Hyperopia, or farsightedness, causes distant objects to be seen clearly, but close up objects appear blurry.
- Astigmatism describes irregularities in the shape or the cornea, which causes blurriness at any distance.
LASIK (Laser-Assisted in Situ Keratomileusis) eye surgery corrects imperfections in the shape of the cornea. Many people who wear corrective lenses have one or all of the above-mentioned vision problems. By increasing the eye’s ability to focus, LASIK surgery does away with the need for glasses or contacts for most patients.
LASIK surgery is a very short process, taking roughly 15 minutes in total. Numbing eye drops are administered to eliminate any pain and discomfort during the procedure. LASIK is a two-step process. First the surgeon uses an instrument called a microkeratome or femtosecond laser to create a flat. Once the flap is created and lifted the surgeon used a specialized laser to reshape the cornea. Once the cornea is reshaped the flap is replaced and the LASIK surgery is complete. Patients will immediately notice an improvement in vision, however vision will be slightly blurry, as if looking through a foggy windshield.
With most LASIK procedures, recovery times are relatively quick, allowing patients to return to many normal activities the same or next day. Some mild discomfort can occur right after the procedure, but patients are advised to go home and nap for a few hours to help the eyes begin to heal. Itching and burning commonly occur, but medicated drops are provided to help patients avoid rubbing their eyes and ease any discomfort. A day after the procedure, the patient must return to Icon to check on vision and ensure healing has begun. Within a few days, the discomfort, along with any light sensitivity, should dissipate. Avoiding certain things such as contact sports, swimming, and hot tubs the first week help improve the recovery process ensure successful results. For the first few months post-surgery, vision may fluctuate in situations such as night driving.
See more information on our LASIK procedure and commonly-asked LASIK questions.
With PRK (photorefractive keratectomy), a laser corrects vision problems such as astigmatism, nearsightedness, and farsightedness by reshaping the eye’s cornea, without the addition of a flap. The laser beam focuses directly on the cornea’s surface as opposed to beneath the flap, in the case of LASIK. After the PRK procedure a bandage contact lens is placed on the eye to aid in healing and to protect the treated area.
PRK was the first type of refractive laser surgery approved by the FDA. Like LASIK, PRK surgery is very quick, often lasting less than 10 minutes per eye. Making the correct choice between LASIK and PRK depends on several factors including your doctor’s recommendations. PRK eye surgery excels at correcting vision for those people with corneas that are of unusual size, shape, or thickness. PRK is also recommended for those who work in law enforcement, martial arts, the military or are firefighters, as there is less chance for complications with the flap.
However, PRK recovery takes longer than LASIK, the healing time for the surface of the cornea is longer, as well as the time before achieving best-corrected vision. For the first week or so, both itchiness and light sensitivity commonly occur. It is recommended that patients do not return to work for several days after the procedure. In some cases patients may not feel comfortable driving for several days after the procedure, as well.
Schedule a free consultation with ICON to see if you are a candidate and start seeing more clearly without the use of contact lenses and glasses.