To see clearly, the cornea and the lens must bend light rays so they focus on the retina which converts the light rays into impulses that are sent to the brain, where they are recognized as images. If the light rays don’t focus on the retina, the image is blurry. Glasses, contact lenses, and refractive surgery try to reduce these errors by making light rays focus on the retina. Refractive errors are caused by an imperfectly shaped eyeball, cornea, or lens — or in the case of presbyopia, a lens that can't change shape enough to focus on close objects — and are of these basic types:
1) Myopia (nearsightedness) where only nearby objects are clear or distinct
2) Hyperopia (farsightedness) where only objects far away are clear or distinct
3) Astigmatism is when images are blurred, regardless of whether they are near or far
4) Presbyopia is a condition that typically develops between ages 40 and 50 and makes it more difficult to see very close. It can be corrected with bifocals or reading glasses, but usually can't be corrected by LASIK or some other refractive surgery.
During the 1980s Radial Keratotomy (RK) was used in the United States. It involved cutting spoke-like incisions to flatten the eye's surface mainly to correct nearsightedness, but results, especially long-term, created problems for some individuals. The main problems were glare, regression, fluctuating vision and other side effects such as night vision problems were common in patients who had RK for higher prescription strengths, while such side effects were less frequent in patients with lower prescriptions. RK is now virtually obsolete.
Currently, a laser procedure called LASIK is the most popular refractive surgery performed in the United States. But there are other types of refractive surgery — including other laser procedures and intraocular lens procedures — that might be an even better choice.
In LASIK and similar procedures, a laser reshapes the curvature of the cornea to alter the way light rays enter the eye. Over the past 25 years, surgical techniques, tools, and procedures for vision correction have evolved rapidly.
In a LASIK procedure, a laser is used to reshape the cornea to improve the way your eye focuses light rays onto the retina and it sounds like the perfect solution if one wants to eliminate the need for glasses or contact lenses. However, before singing up for the surgery there are a few things to think about.
1) The surgery is on a very delicate part of the eye and once performed, it cannot be reversed.
2) As with any surgery, there are risks and possible complications.
3) LASIK may not give you perfect vision. The American Academy of Ophthalmology (AAO) reports that nine out of 10 patients achieve somewhere between 20/20 and 20/40 vision, but 20/40 vision may not be sharp enough for certain work or leisure activities. Even 20/20 does not always mean perfect vision. After cataract surgery about a year ago my vision is technically 20/20. I can read the 20/20 line on the eye chart, but it is fuzzy.
4) Even with LASIK to correct your distance vision, you are likely to need reading glasses in your mid-40s. LASIK surgery cannot correct or prevent presbyopia, the age-related loss of focusing power for seeing near objects.
5) If you are nearsighted and don't need reading glasses, having LASIK may mean you will need reading glasses earlier than if you had not had the surgery.
6) The benefits of the LASIK procedure may diminish over time. More than 10 percent of LASIK patients in the U.S. require a second surgery to restore vision correction. This is more likely for people who were more nearsighted or farsighted, or had higher astigmatism before LASIK.
7) Most insurance plans don’t cover the surgery.
LASIK isn’t for everyone
1) It's not recommended for those under 18 because the vision of people younger than 18 still is changing.
2) Pregnant or nursing. These may change the measured refraction of the eye.
3) You can't be on certain prescription drugs, like Accutane or oral prednisone.
4) Your eyes must be healthy and your prescription stable.
5) General health should be good. LASIK may not be recommended for patients with diabetes, rheumatoid arthritis, lupus, glaucoma, herpes infections of the eye, cataracts, disorders of the cornea, and retinal disease.
6) A history of dry eye from wearing contact lenses, taking certain medications, or some other reason could impact LASIK. You should be screened for dry eye before you have LASIK or other refractive surgery.
One very important consideration is that LASIK surgery corrects one eye for distance vision and the other eye for near vision. During the five weeks between cataract surgeries on my eyes last year, I had this problem and it was certainly annoying. But, I was informed by someone who had LASIK surgery that eventually your eyes (or brain) adjusts and you don't notice it. If you can adjust to this situation, fine. In this case the two eyes no longer work together which causes lower quality vision and a decrease in depth perception. These effects are most noticeable in low lighting conditions or when performing tasks requiring very sharp vision. As a result, the need to wear glasses or contact lenses for distance or near vision when performing visually demanding tasks, such as driving at night, operating dangerous equipment, or performing occupational tasks requiring very sharp, close vision my still be necessary.
Risks and Complications
1) Blindness and irreversible eye damage. In rare cases, errors during surgery or complications after surgery may cause irreversible damage to the eye, including permanent blindness.
2) Vision loss. Even with glasses or contacts it is possible you may not see as well after the surgery as you did with glasses or contacts before the surgery. Or, you may still need glasses or contacts.
3) Severe night vision problems, particularly glare, halos, and/or double vision that can seriously affect nighttime vision.
4) Decrease in sharpness. Objects may appear fuzzy or grayish. Even with good vision on the vision chart, you may not see as well in situations of low contrast like at night or in fog after treatment compared to before.
5) Severe dry eye syndrome. Your eye may not be able to produce enough tears to keep it moist and comfortable. Dry eye not only causes discomfort, but can reduce visual quality due to intermittent blurring and other visual symptoms. This condition may be permanent.
6) Post-surgery infections are always a possibility.
What to Expect Before, During, and After Surgery Before
You’ll need a complete eye examination by your surgeon. LASIK is an outpatient surgical procedure. The only anesthetic is an eye drop that numbs the surface of the eye. The surgery takes 10 to 15 minutes for each eye. Sometimes, both eyes are done during the same procedure; but sometimes, surgeons wait to see the result on one eye before doing surgery on the other.
During surgery the eye is moistened and suction ring is positioned to keep the eye from moving and the cornea in the correct position. A hinged flap of thin corneal tissue off the outer layer of the eyeball is sliced and lifted out of the way and laser reshapes the underlying corneal tissue, and the surgeon replaces the flap, which quickly adheres to the eyeball. There are no stitches and healing is relatively fast.
Just my opinion...vision is too precious to take any unnecessary risks, no matter how small, just to avoid wearing glasses.
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