What can one expect during cataract surgery?
Cataract surgery is the most frequently performed surgery in the United States – and the most successful. Over 95 percent of those who have cataract surgery regain vision levels between 20/40 and 20/20.
Cataract surgery usually lasts less than one hour and is almost painless. Many people choose to stay awake during surgery and have an anesthetic to numb the nerves in and around the eye.
The goal of cataract surgery is to improve the decreased vision that was caused by the cataract. During the surgery, the ophthalmologist removes the cataract, (the cloudy natural lens of the eye), and replaces it with a new artificial lens, called an intraocular lens, or IOL. Cataract surgery will not correct other causes of decreased vision, such as glaucoma, diabetes, or age-related macular degeneration. Many people still need to wear glasses or contact lens after cataract surgery, at least part of the time, for either near and/or distance vision and/or to correct astigmatism.
Patients with natural nearsightedness or farsightedness often also have astigmatism. An astigmatism is caused by an irregularly shaped cornea; instead of being round like a basketball, the cornea is shaped like a football. This can make the vision blurry. In addition to Toric IOLs, astigmatism can be reduced by glasses, contact lenses, and refractive surgery (LASIK or PRK). There is also a procedure called a limbal relaxing incision (LRI), which can be done at the same time as the cataract operation, or as a separate procedure. A limbal relaxing incision (LRI) is a small incision the ophthalmologist makes into your cornea to make its shape rounder. Any attempt at astigmatism reduction could result in over- or under-correction, in which case glasses, contact lenses, or another procedure may be needed. There is no perfect correction for astigmatism and all of the techniques listed above are attempts to reduce but not entirely eliminate astigmatism.
Monovision is a technique in which one eye is focused for distance and the other eye is focused for either intermediate or near vision. With both eyes open most people with monovision feels that they are able to see simultaneously both at near and at distance. The possible drawbacks include a feeling of unsteadiness, loss of depth perception, glare and/ or visual fatigue. Some people who do prolonged reading or close work such as accountants, architects and attorneys often find that they must still wear reading glasses for prolonged close work and some may need to wear glasses for driving, especially at night.
Your ophthalmologist will help you decide on the type of IOL that will replace your cloudy lens. There are different types of IOLs available: standard single vision, accommodating (Crystalens), multifocal (Rezoom and ReSTOR), and “toric” IOLs that reduce your astigmatism. It is important that you carefully complete the Lifestyle Questionnaire to help your surgeon guide that decision.
Single Vision fixed focus IOLs usually provide either sharp vision at distance or sharp near vision. If the lens is focused for distance, then near vision will be blurry. Reading glasses would be necessary to read. Conversely, a single vision lens which focuses the eye for near and reading will give blurred vision in that eye for distance. If the eye is focused for reading/near then glasses would be necessary to see at distance, such as for driving. Standard single vision lenses do not correct astigmatism, and any remaining astigmatism may produce blurring at all distances without glasses.
Toric single vision fixed focus IOLs are fixed focus single vision IOLs that help persons with astigmatism see better for distance OR near than they otherwise would if they had a non-toric single vision IOL. (Although Toric lenses improve the sharpness of your vision at distance OR near without glasses, they do not provide BOTH near and distance vision simultaneously.)
Accommodating IOLs such as the Crystalens are designed to give good distance vision as well as usable intermediate distance vision such as for the computer screen. Most patients are also able to read large type without glasses but some patients will need reading glasses to read small type. Correction of astigmatism, if necessary, is accomplished through limbal relaxing incisions(LRI). Astigmatism correction is included in the fee for this lens.
Multifocal IOLs such as the ReZoom and the ReSTOR are designed to simultaneously give you both distance and intermediate and/or reading vision with each eye. The optical results are sometimes not perfect and some patients are bothered by subnormal distance and/or reading vision. Other common optical side effects include halos around lights at night and reduced vision either in bright or dim light. Correction of astigmatism, if necessary, is accomplished through limbal relaxing incisions(LRI). Astigmatism correction is included in the fee for this lens.
Are lasers used during cataract surgery?
During the past three decades, the techniques and results of cataract surgery in the U.S. have changed dramatically:
- Ophthalmologists have moved from intracapsular cataract extraction as the preferred method to almost exclusive use of extracapsular techniques.
- Smaller incisions have become the standard: Ultrasonic (U/S) phacoemulsification is now the method of choice for most surgeons.
- Improved surgical techniques for removing the anterior lens capsule have decreased the incidence of both intraoperative (during surgery) and postoperative capsular complications.
- Along with these advances have come improved intraocular lens materials and designs, which are especially well suited for use with smaller incisions .
- Improved wound construction allows many wounds to be left unsutured.
- Smaller wounds require shorter recovery time and allow greater intraoperative control and safety.
Despite these advances, however, U/S phacoemulsification techniques are not without potential sight-threatening complications.
Possible complications related to U/S phacoemulsification include corneal or scleral burn, iris trauma, rupture of the posterior capsule, loss of vitreous fluid, cystoid macular edema, and induced astigmatism. These complications may lead to compromised vision prompting investigations into newer techniques of using laser energy to remove cataracts.
The advantages of using a laser to remove cataracts include the ability to use fiber optics with a smaller diameter than typical ultrasonic probes; and direct energy precisely on target tissue by means of a smooth, blunt, stationary probe.
Theoretically, the use of a laser, compared with U/S phacoemulsification:
- reduces heat and vibration in the wound and in the eye
- decreases the chance of capsular rupture
- requires smaller incisions
- allows faster recovery
Currently, Bascom Palmer Eye Institute is one of several sites involved in a clinical study to see if laser energy can safely break the cataract into pieces. This study also will determine if the laser method of cataract removal, called laser photofragmentation or phacolysis, is as good as or better than ultrasound phacoemulsification.