With LASIK, the ophthalmologist (Eye M.D.) uses a laser to reshape the cornea, which is located at the front of the eye. This improves the way the eye focuses light rays onto the retina, at the back of the eye, allowing for better vision. With normal vision, light rays focus directly on the retina.
It is important for anyone considering LASIK to have realistic expectations. LASIK allows many people to perform most of their everyday tasks without wearing corrective lenses. However, those hoping to achieve perfect vision and become completely free of the need to wear eyeglasses or contact lenses run the risk of being disappointed.
Everyone develops the need to wear reading glasses in their 40s or 50s due to presbyopia. If your vision is fully corrected for distance with LASIK, you will need reading glasses to correct for presbyopia once it has developed. If you are nearsighted and do not yet need reading glasses, having LASIK may mean you will need reading glasses at an earlier age than had you not had laser eye surgery.
If you are having LASIK over the age of 40 and are interested in correcting your presbyopia (i.e., decreasing your dependence upon reading glasses), you may want to consider a strategy called monovision. This technique corrects your vision to allow for near or intermediate vision in one eye and distance vision in the other eye. This means that each eye is working independently instead of together. For monovision, your dominant eye — the one you would use to look into the viewfinder of a camera — would become
the distance eye and the other would be used for near vision. With this technique, the brain learns to adapt to eyes set to focus at different distances. Not everyone is comfortable with this difference in focus, especially those who spend a lot their time playing sports or do a lot of night driving. However, many people find they adapt well to monovision when they try it out first, using contact lenses, before having LASIK.
In fact, many preop LASIK patients over 40 are already using monovision with their contact lenses to decrease their dependence upon reading glasses, and are comfortable with it. Contact lenses are actually the best way to demonstrate monovision before surgery, as they most accurately replicate what the patient will see after surgery.
Nevertheless, some patients respond so positively to a “monovision demonstration” with trial frames (spectacles) during the preoperative evaluation that a contact lens trial is not necessary.
If 20/20 vision is essential for your job or leisure activities, consider whether 20/40 vision would satisfy you. More than 90 percent of people who have LASIK achieve somewhere between 20/20 and 20/40 vision without eyeglasses or contact lenses.
Also, you would need to be comfortable with the possibility that you might need a second surgery (“retreatment”) in order to attain your desired results, or that you might need to wear glasses for certain activities, such as reading or driving at night.
The greater your refractive error (that is, the greater your nearsightedness, farsightedness or astigmatism, or combination of these conditions), the more likely you would require retreatment or glasses.
It is important to discuss your lifestyle, including your work and recreational and leisure activities, with your prospective surgeon before deciding to go ahead with LASIK. Some work, sports and other activities are not compatible with LASIK.
How LASIK Works
LASIK is performed in an outpatient surgical setting, with the patient reclining under a surgical device called an excimer laser. First, your eye is made numb with a few drops of topical anesthetic. An eyelid holder, called a speculum, is placed between the eyelids to keep them open and prevent you from blinking.
A suction ring placed on your eye lifts and flattens the cornea and prevents your eye from moving. You may feel pressure from the eyelid holder and suction ring, similar to a finger pressed firmly on your eyelid. From the time the suction ring is placed on your eye until it is removed, vision appears dim or goes black.
LASIK with laser making corneal flap The surgeon then creates a hinged flap of paper-thin corneal tissue using an automated microsurgical device, either a laser or an instrument called a microkeratome blade.
The corneal flap is lifted and folded back. The excimer laser, which has been preprogrammed with measurements specifically for your eye, is then centered above your eye.
You will look at a special pinpoint of light (called a fixation light or target light) while the laser sculpts the exposed corneal tissue. After the laser has reshaped your cornea, the surgeon replaces the flap in position and smoothes the edges without placing any stitches. Your corneal flap will never adhere to the surface of the eye with quite the same strength it did prior to the surgery, so there is a rare but possible risk of the flap becoming displaced with sufficient force.
After surgery, you should avoid rubbing the eye, which may cause the flap to shift out of place. To help protect the cornea as it heals, the surgeon may place a transparent protective shield over your eye. The shield may only be needed at night to prevent you from rubbing the eye during sleep.
An eye shield worn after LASIK You should arrange to have someone take you home after the surgery. Taking a nap or simply relaxing for the rest of the day is recommended. Usually your vision will be clear enough to drive to the follow-up visit the next day. The doctor may advise waiting several days before you resume a normal work schedule. The doctor should advise you on how long you should wait before resuming sports, exercise, or strenuous activity.
After LASIK surgery, you will receive eyedrops to help prevent infection and inflammation during the healing process and to alleviate dryness. You must be sure to follow any instructions from your doctor and return for follow-up appointments as directed.
Bear in mind that it may take three to six months for vision to stabilize completely. All LASIK patients should ask their doctors for a record of their pre-LASIK correction prescription. This information is important for you to give to the doctor who may perform a future cataract surgery or other eye disease diagnosis and treatment.
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