Refractive Surgery is a type of elective procedure that corrects refractive errors such as nearsightedness, farsightedness, and astigmatism.
There are two main types of refractive surgery: LASIK (laser in situ keratomileusis) and PRK (Photorefractive Keratectomy). Both use an excimer laser to change the shape of your cornea. For you to see clearly, light has to go through your cornea, through the lens, and to the back of your eye to the retina. With any refractive error, the shape of the cornea or lens prevents light from bending properly. When the light is not focused on the retina, the vision is blurry.
The excimer laser in LASIK ablates tissue with submicron precision. Wavefront-optimized or guided LASIK (or custom LASIK) uses a detailed topographical map of your cornea to allow your ophthalmologist to create custom changes to the final treatment plan.
During the surgery
Both LASIK and PRK are performed in a laser surgery suite. Your eye will first be numbed with eye drops, after receiving some oral relaxing medication. The eye will be held open to keep it from blinking. During LASIK, a suction ring is placed on the eye, and at this point you feel pressure and the vision will go dim or black. Using the laser, your surgeon will make a paper-thin flap in the cornea tissue. The flap is lifted, and you are then asked to stare at a target so that your eye does not move. Your surgeon then reshapes your cornea using a laser, which has been programmed with measurements for your eye. After reshaping the cornea, your surgeon folds the flap back into position and smoothes the edges. The flap adheres on its own after several minutes.
During PRK, there is no flap created. The top corneal layer, the epithelium, is removed using either a brush or alcohol solution. Your surgeon then uses the laser to reshape the surface of the cornea, using pre-programmed measurements. A bandage contact lens is placed over your eye to help it heal. There is some discomfort for several days after the procedure, and most people take a few days off.
Is LASIK/ PRK right for me?
Long term contact lens wear is not healthy for the eye and can result in a lack of oxygen and chronic redness and dry eye. Most people undergo refractive surgery when they either become contact lens intolerant or no longer want to wear glasses or contact lenses.
You must first meet certain requirements in order to be eligible for refractive surgery:
- Your vision should be relatively stable, with your glasses/ contacts prescription not having changed in the last year
- You should be at least 18 years old, and preferably at least 21 years old, when vision is more likely to have stopped changing.
- The amount of your refractive error must be one that is correctible by a laser, so that the cornea does not end up being too thin.
- A full ophthalmologic evaluation must first be performed and will involve examining:
- Overall health of your eyes
- Measurements of your corneas
- Your refractive error
- Your pupil size
- Tear production
Some patients are not candidates for refractive surgery. Here are some conditions that will exclude you:
- Degenerative dystrophies/ cornea disease
- Corneas that are too thin
- Recurrent corneal abrasions
- Extreme levels of myopia, hyperopia, or astigmatism
- Pregnant or nursing women
- Uncontrolled diabetes
- Advanced glaucoma or retinal disease
- History of certain eye infections, particularly viral
Other things to consider after refractive surgery:
- Lens calculations for cataract surgery are less reliable when you need cataract surgery later on in the future; it is wise to save all records from before refractive surgery.
- Most very near-sighted patients (-4.00 or higher) are at increased risk of retinal tears and detachments for the rest of their lives. If you are very near-sighted and have this corrected by refractive surgery, you are still at higher risk and must have yearly dilated exams.
- The intraocular pressure measured on a thinner cornea will always be artificially lower than the true intraocular pressure. This may make a diagnosis of glaucoma delayed; thus it is important for you to mention to every eye doctor you see in the future that you had refractive surgery.
1. American Academy of Ophthalmology Basic and Clinical Science Course Refractive Surgery, 2012-2013
2. American Academy of Ophthalmology Practice Management. LASIK
. American Academy of Ophthalmology Practice Management. Photorefractive Keratectomy
Dr. Yuna Rapoport received her MD from the honors program at Northwestern University Feinberg School of Medicine, completed ophthalmology residency at Vanderbilt University, and completed an extra year of fellowship at Harvard Medical School. She performs refractive, cornea, and cataract surgery. Each of Dr. Rapoport’s patients receives individualized and expert care. Her work regarding advances in eye care treatments has been published in many leading medical journals and presented at major ophthalmologic meetings. She is on staff and teaches trainees at New York Eye and Ear Infirmary and Mt Sinai St. Luke’s Roosevelt. She is currently accepting new patients at: Eastside Eye Surgeons - 178 East 71st Street, New York, NY 10021. Phone: (212) 650-0400, Website: www.eastsideeyesurgeons.com