As we age, the natural crystalline lens of the eye may lose some of its elasticity and thereby its ability to accommodate to nearby objects. This condition, known as presbyopia, usually begins around the age of 40 and can most often be comfortably corrected through the use of reading glasses or contact lenses.
The correction of presbyopia is now also possible through various procedures listed below:
LASIK or PRK will not prevent the need for reading glasses in patients over 40 years of age.
PRELEX® (Presbyopic Lens Exchange)
PRELEX (Presbyopic Lens Exchange) is a procedure used to correct presbyopia for patients over the age of 45 who want to reduce their dependence on reading glasses. Using the same procedure that has been used for millions of patients undergoing cataract surgery, the PRELEX procedure involves removing the eye's natural lens and replacing it with an artificial lens implant. With the PRELEX procedure, multifocal intraocular lenses are used that allow the eye to focus for distance and NEAR – unlike other methods of refractive surgery which alter the shape of the cornea.
Although the PRELEX and cataract procedures are the same, the reasons for performing the surgery differ. While cataract surgery is done to remove a patient's cloudy lens; PRELEX is used to correct presbyopia and distance vision thereby reducing a person's dependence on glasses or contact lenses.
PRELEX is used for the following types of patients:
- Patients with very high levels of nearsightedness or farsightedness.
- Patients who wish to eliminate their dependence on bifocals or reading glasses.
- Patients who have corneas that are too thin for LASIK.
- Patients who may be showing signs (even without symptoms) of developing cataracts.
How Can You Benefit from PRELEX?
- Recovery of unaided distance vision (no glasses needed for driving in over 99% of patients).
- Recovery of near vision in PRELEX patients with the ReSTOR multifocal lens (no glasses needed for reading in over 80% of patients).
- Prevention of cataracts: With PRELEX surgery, the risk of developing a cataract (or clouding of the lens) in the eye is completely eliminated. (Cataract surgery is required in over half the population by age 80 and occurs at a significantly younger age in patients with large refractive errors).
- FDA data shows that following PRELEX surgery with the Alcon RESTOR intraocular lens:
- 80% of patients never wore glasses
- 17% of patients sometimes wore glasses
Conductive Keratoplasty (CK)
Conductive Keratoplasty (CK) is a non-laser vision correction procedure that uses radio waves to help restore near vision for patients with presbyopia. CK was designed for farsighted individuals (hyperopes) over the age of 40 who would like an alternative to wearing reading glasses. CK is not intended for nearsighted (myopic) patients.
CK uses the controlled release of radiofrequency (RF) energy to heat and shrink corneal tissue. This steepens the cornea; thereby allowing light to properly focus on the retina. The RF energy is gently applied to the eye in a circular pattern; avoiding the pupil entirely.
The procedure itself involves first numbing the eye with drops. A treatment pattern is then imprinted with rinse-away dye. Finally, a Keratoplast tip is used to apply the RF energy. As with other vision correction procedures, mild discomfort and light sensitivity may be experienced for a few days.
Monovision is a form of treatment for presbyopia. One eye is fully corrected for distance vision, while the other is under corrected. This will leave the under corrected eye with a mildly myopic prescription (nearsighted) for near vision.
The distance vision in this under corrected eye is blurrier, but the near vision is sharper. This small amount of myopia allows a presbyopia patient (over 40 years old) to see clearly up close, and therefore can avoid or reduce the need for reading glasses.
This situation is a compromise. It does not eliminate presbyopia, but improves it. Distance vision is not perfect, but good. Near vision is not perfect, but good enough to function. Monovision will allow someone with presbyopia to read a label, tell the time on his or her watch, shave in the mirror, or read a menu in the restaurant. Very fine detailed near tasks will still require reading glasses, as well as prolonged near tasks such as reading a book for several hours. Eventually with age, almost everybody will still require reading glasses for up close tasks.
It may take two to three weeks for the brain to adjust to Monovision. Some people love it; others cannot tolerate the imbalance between the two eyes. Monovision should first be tried in contact lenses, before it is undertaken with laser treatment.
Disadvantages of Monovision:
- Decreased depth perception, particularly for sports.
- Reading very fine print or reading for long periods of time will still require reading glasses.
- Driving long distances at night may be more difficult. (This can be overcome by wearing corrective glasses while driving.)
For more on other eye problems: