If you’re like most people, you’re not entirely happy with wearing lenses to correct your vision. Maybe it’s the way your glasses steam up when you come inside in winter. Perhaps it’s switching back and forth from regular glasses to sunglasses in summer, straining to read your alarm clock when you wake in the morning, or getting dust under a contact lens at just the wrong moment. Maybe lenses are even limiting your choice of career, or the sport you play.
Whatever the problems with glasses or contact lenses, refractive surgery offers an alternative that could help you see better without them.
Meet Our LASIK Doctors
Sarah M. Nehls, MD
Professor, Cornea and Anterior Segment Service Chief
Patricia C. Sabb, MD
Assistant Professor
Heather Potter, MD
Professor, Ophthalmic Pathology Service Chief
Evan J. Warner, MD
Assistant Professor
What is refractive surgery?
Refractive surgery corrects your vision by changing the shape of the cornea, the transparent layer that covers the outer surface of the eye. Eye surgeons at UW Health Eye Clinics currently perform several types of refractive surgery:
- Photorefractive keratectomy (PRK) uses an excimer laser to remove a thin layer of the cornea to correct nearsightedness, farsightedness and astigmatism
- Laser In Situ Keratomileusis (LASIK) involves the use of a special instrument to raise a flap of corneal tissue, the excimer laser is then used to remove a thin layer of cornea underneath to treat nearsightedness, farsightedness and astigmatism
- IntraLASIK is the first blade-free laser technology using a laser to make a safer, more precise corneal flap during LASIK surgery
- Custom LASIK uses a wavefront analyzer to guide the treatment of additional imperfections in the optical system of the eye called higher order optical aberrations. This customized treatment can reduce the risk of glare, halos around lights or ghost images and deliver better results than current conventional treatment
To understand how refractive surgery corrects your vision, it helps to understand how the eye works.
How does the eye work?
The eye functions like a camera. Light comes in through the cornea, which focuses the light rays as they pass through the pupil and the lens. The iris, which surrounds the pupil, works like a camera shutter and controls the amount of light that enters the eye. In normal eyes, the cornea and lens bend light so that it focuses directly on the retina, the light sensitive tissue in the back of the eye. The retina changes light into electrical impulses that travel via the optic nerve to the brain.
Poor vision results when the cornea and the lens focus light too far in front of or behind the retina. Corrective lenses work by allowing the light to focus directly on the retina.
What is nearsightedness (myopia)?
When someone is nearsighted, light entering the eye is focused in front of the retina, instead of directly on it. People with myopia see near objects more clearly, while far objects appear blurry and out of focus.
Myopia is an inherited condition, which usually starts in childhood and stabilizes in the late teens or early twenties.
What is farsightedness (hyperopia)?
Farsightedness or hyperopia is a condition that occurs when light entering the eye is focused behind the retina. People with mild farsightedness have difficulty seeing objects up close but distant objects may be seen clearly. Higher amounts of hyperopia may result in the inability to see objects well at any distance.
What is astigmatism?
Astigmatism is the eye condition that occurs when the curvature of the cornea is not uniform, causing light to fall unevenly on the retina. This irregularity makes objects appear blurry or “ghosted.”
How does refractive surgery correct vision?
Laser vision correction uses an excimer laser to treat nearsightedness, farsightedness, and astigmatism. One laser pulse removes 1/4000 millimeter of tissue, an amount so small it would take 200 pulses of the laser to etch through a human hair. Controlled by a computer, the laser is an extremely accurate tool that your doctor can use to reshape your cornea. The results of your eye exam are entered into the computer, which calculates the precise depth and pattern of tissue to be removed. Because the laser does not generate heat, surrounding tissue is unharmed.
TYPES OF REFRACTIVE SURGERY

Photorefractive keratectomy (PRK)
PRK uses an excimer laser to shave ultra thin layers of tissue from the cornea. During PRK treatment, the surface layer of the cornea (epithelium) is removed by gentle scraping, followed by the excimer laser. A bandage contact lens is placed on the eye to aid healing after the laser treatment is completed.

LASIK
LASIK combines the use of a special instrument known as a microkeratome to create a “flap” of corneal tissue. The laser is then used, similar to PRK, to treat your nearsightedness, farsightedness and/or astigmatism under this flap. After the laser treatment is performed, the corneal flap is then replaced and acts like a natural bandage contact lens.

IntraLASIK
IntraLASIK uses a laser that delivers a near infrared beam of light to create a flap from below the surface of the cornea, replacing the hand-held microkeratome blade with computer-guided laser precision.

Custom LASIK
Custom LASIK is performed after measuring a wavefront map of the patient’s eye. A customized laser treatment is then designed that treats not only the eyeglass prescription, but also higher-order optical imperfections that can lead to visual distortions that affect the quality of your vision.
How do PRK and LASIK differ?
PRK offers patients an excellent option to achieve their desired vision correction, but recovery of vision is delayed until the surface layer of the cornea heals. Your doctor may recommend separating the treatment of each eye by one week. LASIK involves less initial discomfort and allows patients to see better sooner after surgery. Both PRK and LASIK produce about the same final visual result. IntraLASIK allows for construction of a thinner, more precise corneal flap and may produce more precise refractive surgery outcomes.
Who is a potential candidate for refractive surgery?
People considering refractive surgery should be at least 18 years old, have a record of stable eye exams for at least 18 months, have no corneal disease and have otherwise healthy eyes. Most patients with low or moderate degrees of nearsightedness will have near normal uncorrected vision after surgery. Those with higher degrees of nearsightedness may be better suited for IntraLASIK.
How can I tell whether refractive surgery is right for me?
UW refractive surgeons, Dr. Sarah Nehls, Dr. Heather Potter and Dr. Patti Sabb will discuss the best laser vision correction option customized to your eyes and answer all your questions when you schedule a no-charge screening to determine your candidacy for the procedure. A complete eye exam will be necessary prior to surgery.
For more information about our free seminars or to schedule an eye exam, call (608) 265-2020.
How much does refractive surgery cost?
Fees for preoperative and postoperative care charged by your family eye doctor are separate from those fees charged for the procedure by UW Health and may vary. Please consult with your eye doctor prior to your surgery to understand these costs, or call (608) 265-2020 for a current listing of UW procedure fees.
Why choose UW Health Laser Vision Correction?
- UW Health Eye Clinics are reputable, national leaders in eye care. Our department is currently the second leading recipient of eye research grants from the National Eye Institute/National Institute of Health.
- UW refractive surgeons offer a variety of choices for laser vision correction – PRK, custom LASIK, and now IntraLASIK – the first blade-free laser technology that enables our physicians to customize your vision correction to your eyes.
- UW refractive surgeons use the latest technology to provide laser vision correction for their patients:
- The VISX S4 Excimer Laser has the most up to date features such as active eye tracking and iris registration to provide the safest, most precise means of delivering a custom treatment to your eyes. The VISX S4 Laser System recently received FDA approval for custom treatment of high myopia providing the highest range of treatment available in the US market.
- The Intralase Femtosecond Laser is used to perform the critical first step of the LASIK procedure; creating the corneal flap. UW refractive surgeons are among the first in the area to provide this all laser surgical technique for performing LASIK surgery.
- Patients benefit from a dedicated staff who can answer questions, facilitate convenient appointments and monitor progress.
- As an academic medical center, UW Health Eye Clinics puts a strong emphasis on education for both patients and practicing eye care professionals. Seminars are held regularly and patients benefit from a thorough explanation of the procedure from staff and physicians prior to surgery.
SURGERY AND RECOVERY
What happens during the procedure?
Patients are awake and comfortable during the laser procedure. You may be given a sedative for relaxation. Your physician will administer anesthetic drops to numb your eye and your eyelids are kept open with a small instrument to prevent blinking. The entire procedure usually takes 10 to 15 minutes to complete. Your surgical visit on the day of your procedure will probably last less than one hour.
What about recovery?
You will receive eye drops to aid the healing of your eye to start at home on the day of your procedure. You may leave the laser center shortly after your surgery, and you will need a friend or family member available to drive you home. We recommend rest for the remainder of the day. You will wear eye shields or goggles to protect your eyes until you are seen by your doctor the following day. Have a pair of sunglasses handy–your eye may be sensitive to bright sunlight as it heals. You should also refrain from swimming for four weeks and wear protective eyewear when playing active sports.
Are there any side effects?
As with any type of surgery, complications are possible. Fortunately, with refractive surgery, serious or long-term side effects are rare. The most common are:
- Light sensitivity (one to two months)
- Glare at night, for example, from oncoming headlights (variable length)
- Dry eyes requiring use of artificial tears for one to three months
Can I continue to see my own eye doctor?
The UW eye surgeons work cooperatively with eye doctors from throughout the area to provide the full range of refractive surgery services. Your family eye doctor normally provides your preoperative care including your initial eye exam. The surgical planning and the surgery itself is then performed by Dr. Nehls or Dr. Sabb. Following the procedure, your follow-up care may then be provided by your family eye doctor.