Post: What’s the difference between PRK and LASIK?

Price: Both improve vision by reshaping the eye’s covering or cornea with a cool ultraviolet light beam. The difference lies in how the surgeon reaches the inner layer of the cornea in order to treat it. PRK involves removing tiny bits of the cornea’s top surface that gradually grow back. With LASIK, surgeons make a corneal flap that can be repositioned after treatment. LASIK is the more comfortable and convenient option. But when a thin cornea rules out LASIK, PRK is often the treatment of choice.

Post: How do newer lens implants work?

Price: Standard lens implants such as those used in cataract surgery replace the eye’s natural lens. But the implantable contact lens (ICL), or Visian lens, leaves the crystalline lens in place. ICLs are situated in front of or behind the colored part of the eye and can be removed if necessary.

Post: Who is a good candidate for an ICL?

Price: ICLs are especially beneficial for those with moderate to severe astigmatism or nearsightedness. For instance, research shows that ICLs provide better visual acuity than LASIK for people who can only read the top few lines of an eye chart. These lenses are also excellent options for those with very dry eyes that can worsen after laser surgery, and when the cornea is too thin for LASIK, which, as mentioned, requires making a flap in corneal tissue.

Post: Does vision-correcting surgery offer more than an improved appearance and convenience?

Price: Certainly. LASIK and lens implants improve functional vision compared to glasses and contacts, especially when people engage in outdoor activities or exercise. Safety is another big plus of “unaided” visual correction because people don’t need to change and clean their contacts—not just when camping, but in day-to-day living. Additionally, people who require thick lenses due to severe astigmatism often experience less visual distortion with these surgeries than with glasses or contacts.

Post: What about cost and insurance coverage?

Price: The costs of PRK and LASIK are similar and some policies offer partial coverage. ICLs run about $2000 more, an amount generally paid out-of-pocket. Most practices offer payment plans.

Of course, do your homework. Talk to friends who had vision correction. And before scheduling your procedure, ask your surgeon how often he or she has done it.

Francis Price, M.D., is medical director of Price Vision Group in Indianapolis and founder of the Cornea Research Foundation of America (cornea.org).

Optical Options for Getting Rid of Glasses The Saturday Evening Post

The Post interviewed Dr. Ronald Krueger of the Cleveland Clinic Cole Eye Institute—a veteran of 18,000 refractive surgery procedures—about why vision sometimes gets worse after LASIK and how to avoid or treat this perplexing post-op problem.

To frame the discussion, however, let’s first take a quick look at the eye, specifically its outmost covering, the cornea, which provides two-thirds of the eye’s focusing power.

How well you see depends on the shape and curve of your cornea. A normal cornea is smoothly rounded with even curves from side to side and top to bottom. Vision problems—or refractive errors—affecting about 120 million people in the United States develop when the cornea becomes too curved (nearsightedness), too flat (farsightedness), or curves more in one direction than in another like the back of a spoon (astigmatism).

Eyeglasses and contacts correct refractive errors, but LASIK surgery is an increasingly popular option for convenience and comfort.

So, here’s the rub.

During LASIK, the surgeon creates a flap in the eye’s cornea and then uses a laser to reshape it for good vision correction, explains Dr. Kreuger. In a relatively few cases, the cornea weakens after surgery (a condition called ectasia) and loses its ability to maintain the desired shape. As a result, vision blurs and gradually deteriorates.

We asked Dr. Krueger to discuss the latest information about the symptoms and risks for post-LASIK ectasia, and new advances in what doctors can do when it occurs.

Post: What are the symptoms of post-LASIK ectasia?

Dr. Krueger: Patients with ectasia lose visual acuity—some immediately, others months or even years after the surgery. Images become distorted as the cornea loses its rounded shape, and most find they need new lenses or progressive glasses as those changes occur.

Post: How common is it?

Dr. Krueger: Post-LASIK ectasia parallels keratoconus, a naturally occurring condition in which, although no surgery has taken place, the structural integrity of the cornea is not maintained and begins to bulge in certain ways that distort vision. Probably one out of 2,000 people in the population have keratoconus.

LASIK-induced ectasia, while rare, is presumed to be more prevalent in people with subclinical keratoconus. In other words, patients with previously unrecognized corneal weakening may develop a more prominent problem after LASIK.

Post: Who is most at risk?

The most common risk factor is an irregularity on the corneal topography map, a tool we utilize to help screen out individuals who are not suitable candidates for LASIK surgery. As mentioned, having an irregular or steep cornea may be a telltale sign of subclinical keratoconus that may contribute to post-operative ectasia.

Surgeons also look very carefully at a risk score system that is based on published data collected over many years from large groups of patients who developed post-LASIK ectasia. In developing this system, investigators assigned a certain amount of risk to various factors. For example, corneal thickness less than A amount might have B amount of risk toward ectasia. A topography map showing C amount of irregularity may contribute D amount of risk. Being young presents more risk because the cornea gets a little stiffer with age. Then, they developed a way to tabulate an overall score from the list of individual risks.

While the scoring system is published and based on actual data, it has been criticized. Many patients who fit or exceed that score have done perfectly fine and never developed ectasia. But LASIK surgeons do consider this score before doing surgery in order to avoid this phenomenon.

Post: Are topography maps standard of care in LASIK surgery?

Dr. Kreuger: Yes. But they aren’t definitive. Surgeons have to consider other factors.

Post: Does ectasia usually show up in both eyes?

Dr. Kreuger: It can initially develop in one eye, but the potential could exist in both eyes.

Post: What can be done to help people with post-LASIK ectasia?

Dr. Kreuger: The primary treatment is contact lenses to provide a new, smooth shape for the eye to look through.

What has come along for keratoconus, and is showing benefit for post-LASIK ectasia, is a procedure called crosslinking. Collagen crosslinking is a photochemical method of applying vitamin B-2 (riboflavin) drops on the eye and then shining an ultraviolet light that activates the riboflavin to help create little links in the cornea that make it stronger. It is being used in countries around the world, and FDA trials are underway in the United States.

Post: So this is an experimental procedure at this point?

Dr. Kreuger: It’s an investigational procedure in the United States. But it has been investigated in other countries and has shown good success.

Post: Are corneal transplants an option?

Dr. Kreuger: In advanced cases, yes. A transplant will replace the irregular and weak cornea with a stronger one. Then, you can correct it. But that’s a pretty advanced procedure. Corneal transplants may also be considered when crosslinking is not a good option or has been tried and is not fully correcting the problem.

Post: What advice would you offer to people considering LASIK?

Dr. Kreuger: I would suggest several things: 1) Go to more than one place to have your eyes evaluated so that you can get a sense of what doctors are saying at one place versus another. 2) Do some homework so you can ask lots of questions. 3) Make sure you are going to a place that has a stellar reputation for eye care in general. 4) Find an experienced doctor who has good judgment and the patient’s best interests at heart. 5) Ultimately, find the latest technology. Sophisticated imaging devices are now available to help determine which eyes have any risk for keratoconus or ectasia. Hopefully, there will be even newer and better tools in the future.

When LASIK Surgery Goes Awry The Saturday Evening Post