Glasses or contact lenses can correct vision, but reshaping the cornea itself also will provide the necessary refraction. Your eye is a complex and compact structure measuring about 1 inch 2.
It receives millions of pieces of information about the outside world, which are quickly processed by your brain. With normal vision, an image is sharply focused onto the retina. In nearsightedness myopia , the point of focus is in front of the retina, making distant objects appear blurry.
With normal vision, an image is sharply focused onto the surface of the retina. In farsightedness hyperopia , your cornea doesn't refract light properly, so the point of focus falls behind the retina.
This makes close-up objects appear blurry. LASIK surgery may be an option for the correction of one of these vision problems:. Your eye doctor will talk with you about whether LASIK surgery or another similar refractive procedure is an option that will work for you. Complications that result in a loss of vision are very rare. But certain side effects of LASIK eye surgery, particularly dry eyes and temporary visual problems such as glare, are fairly common. These usually clear up after a few weeks or months, and very few people consider them to be a long-term problem.
Dry eyes. LASIK surgery causes a temporary decrease in tear production. For the first six months or so after your surgery, your eyes may feel unusually dry as they heal.
Dry eyes can reduce the quality of your vision. Your eye doctor might recommend eyedrops for dry eyes. If you experience severe dry eyes, you could opt for another procedure to get special plugs put in your tear ducts to prevent your tears from draining away from the surface of your eyes.
Glare, halos and double vision. You may have difficulty seeing at night after surgery, which usually lasts a few days to a few weeks. You might notice increased light sensitivity, glare, halos around bright lights or double vision. Even when a good visual result is measured under standard testing conditions, your vision in dim light such as at dusk or in fog may be reduced to a greater degree after the surgery than before the surgery.
Certain health conditions can increase the risks associated with LASIK surgery or make the outcome less predictable. Doctors may not recommend laser refractive surgery for you if you have certain conditions, including:. LASIK surgery is usually not advisable if you:. Your doctor will discuss whether you're a candidate for the procedure or other similar procedures.
Long-term results from LASIK tend to be best in people who are carefully evaluated before surgery to ensure that they are good candidates for the procedure.
If you wear contact lenses, which can change the shape of your cornea, you'll need to completely stop wearing them and wear only your glasses for at least a few weeks before your evaluation and surgery.
Your doctor will provide specific guidelines depending on the type of contacts you wear and how long you've been a contact lens wearer. During the evaluation, your eye doctor will ask about your medical and surgical history and give you a comprehensive eye examination to evaluate your vision and assess whether you can undergo the procedure safely.
Your eye doctor will also measure your cornea, noting the shape, contour, thickness and any irregularities. Your eye doctor will evaluate which areas of your cornea need reshaping and determine the precise amount of tissue to remove from your cornea.
Doctors generally use wavefront-guided technology to evaluate your eye in detail before LASIK surgery. In this test, a scanner creates a highly detailed chart, similar to a topographic map, of your eye. The more detailed the measurements, the more accurate your eye doctor can be in removing corneal tissue. Before surgery, your doctor will discuss the risks and benefits of LASIK surgery, what to expect before and after surgery, and any questions you may have.
LASIK surgery is usually completed in 30 minutes or less. During the procedure, you lie on your back in a reclining chair. How does laser eye surgery work? A cool beam advanced laser makes subtle adjustments to the shape of the surface of your eye the cornea , correcting its tiny imperfections and making your vision clearer and sharper.
Due to the anaesthetic drops which are applied before the procedure, laser eye surgery itself is generally pain-free , but following the treatment, patients may feel some discomfort in the early stages of healing.
The level of discomfort you experience depends upon the type of surgery you've undergone, but any pain will be short-lived, and you'll be able to enjoy the benefits of improved vision within a matter of days.
The good news is, the majority of people are. However, the best way to confirm your suitability for laser eye surgery is to attend a free consultation with one of our expert optometrists. Here, you will also have the opportunity to ask more in depth questions about how laser eye surgery works. Your eye doctor will perform a thorough eye exam to ensure your eyes are healthy enough for the procedure. He or she will evaluate: the shape and thickness of your cornea; pupil size; refractive errors myopia, hyperopia and astigmatism ; as well as any other eye conditions.
The tear film on the surface of your eyes also will be evaluated, and a precautionary treatment may be recommended to reduce your risk of developing dry eyes after LASIK.
Usually, an automated instrument called a corneal topographer is used to measure the curvature of the front surface of your eye and create a "map" of your cornea. With wavefront technology associated with custom LASIK , you also are likely to undergo a wavefront analysis that sends light waves through the eye to provide an even more precise map of aberrations affecting your vision. Your eye doctor also will ask you about your general health history and any medications you are taking to determine if you are a suitable candidate for LASIK.
You should stop wearing contact lenses for a period of time advised by your doctor typically around two weeks before your eye exam and before the LASIK procedure. This is because contact lens wear can temporarily alter the natural shape of your cornea. Before your LASIK surgery begins, numbing eye drops are applied to your eye to prevent any discomfort during the procedure. Your doctor may also give you some medication to help you relax.
Your eye will be positioned under the laser, and an instrument called a lid speculum is used to keep your eyelids wide open. The surgeon uses an ink marker to mark the cornea before creating the flap. A suction ring is applied to the front of your eye to prevent eye movements or loss of contact that could affect flap quality.
After the corneal flap is created, the surgeon then uses a computer to adjust the excimer laser for your particular prescription. You will be asked to look at a target light for a short time while your surgeon watches your eye through a microscope as the laser sends pulses of light to your cornea. The laser light pulses painlessly reshape the cornea, although you may feel some pressure on your eye.
You'll also hear a steady clicking sound while the laser is operating.
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