After refractive surgery, contact lens patients may require trial fitting period

Issue: June 1996

Randy McLaughlin, OD, an assistant professor of clinical ophthalmology at the Ohio State University Department of Ophthalmology, treats a large number of refractive surgery patients who often need contact lenses postsurgically. Here he discusses the education, fitting and follow-up care for these patients.

Primary Care Optometry News: Many patients undergo refractive surgery because they do not want to wear contact lenses or glasses again. How do you break the news to them that they still might have to wear them?

Randy McLaughlin: A lot of that has to do with the refractive surgeon and how it is presented to the patient. Really good refractive surgeons warn patients—especially patients with higher prescriptions—that they can get a nice reduction in their amount of correction, but that there is the possibility that they will need some sort of visual correction after the surgery. If the patients are prepared for that, and their expectations are the same as the surgeon's, that blow is easy to overcome.

For patients who haven't had that kind of indoctrination, we just present it to them that in terms of the amount of correction they've had, how their eye has healed and even after several procedures, this is the maximum amount of reduction the surgeon was able to obtain at the present time with the available state-of-the-art surgical technique. Most people understand that and accept it.

PCON: Do you recommend that optometrists who are comanaging these patients should have a big role in educating the patients before the surgery?

McLaughlin: Absolutely. I do not see a lot of contact lens patients wanting to give up their lenses and have this surgery performed. They often ask me, "What do you think about that surgery?" and I give them an objective presentation. After that, most of them say they are not ready to have surgery done.

A lot of people who are having the surgery don't have the high expectations of precise visual acuity that contact lens wearers have. These are people who either have failed with contact lenses due to vision or comfort problems or people who admit they will not take care of contact lenses enough, and they don't want to worry about an infection. I think there are two types of expectations: contact lens wearers who want to see 20/15 or better; and refractive surgery patients, who accept that success is 20/40 vision. To many contact lens wearers, that's not acceptable.

PCON: This is a two-part question, for radial keratotomy (RK) patients and photorefractive keratectomy (PRK) patients. What special considerations do you have to keep in mind when you are fitting these patients with contact lenses? Is it different for RK and for PRK patients?

McLaughlin: It absolutely is different. I almost wish it were a law that anyone who has had refractive surgery must have their pre-keratometric readings and their pre-refractions on an embossed card they carry in their wallet so a lens-fitting doctor can have that valuable information.

Anyone with altered corneal topography, whether it's due to an injury, a condition such as keratoconus, penetrating keratoplasty or refractive surgery, is certainly a challenge for the contact lens fitter. All of the empirical fitting formulas are, unfortunately, out the window. Every patient who has had their corneal topography altered has to be viewed as an individualistic fit. Obviously the individualistic type of fit of an RK patient is much more of a challenge than a PRK patient.

I reviewed the literature high and low for a straightforward, almost cookbook way to fit a post-refractive surgery patient. Unfortunately there isn't one, because each patient has a different topography. It's just like there's no one way to fit keratoconic patients because they all present slight differences in how they need to be fit. RK patients are much tougher to fit because they often have a more distorted topography resulting in irregular astigmatism, and because of that a straightforward, easy-to-fit soft lens is often not acceptable in terms of fit or visual quality.

The majority of them are fitted with a gas-permeable lens. The initial lens selection, more times than not, is based on the power and the base curve of their pre-keratometric and pre-refraction empirical readings, and then it's modified slightly after that, to provide optimal vision.

Another option is a soft toric lens. That is controversial, because it is a soft lens and covers up the incisions, which could lead to neovascularization. But if it's followed closely, it is an option. Finally, one lens that should not be ignored is the Soft-Perm lens: the lens with the hard center portion and the soft periphery.

Because of the flattening with PRK, often those patients are more or less spherical. So, fortunately, we are often able to fit them with a normal, conventional soft lens, many times with a slightly flatter base curve. Also, there are some options of toric soft lenses. And, of course, the patients are followed closely. Some of the one-size-fits-all lenses don't work well in these patients, so it is, again, a trial-fitting type of procedure with a soft lens. Custom lenses or lenses with different base curve selections and diameters are very helpful in this type of patient.

PCON: What kinds of problems or complications do you need to watch out for with post-refractive surgery patients?

McLaughlin: The main thing is that you don't want to see any infections whatsoever. You want to make sure first that the eye heals, so you need to follow these patients much more closely. After the lens is fitted, the main worry is about covering the cornea. When you cover the cornea, you deprive a healing cornea of oxygen and have the potential of vessel ingrowth in the incision areas. Because of that, the altered corneal topography, and because it's a fairly new procedure, we need to closely scrutinize follow-up care.

PCON: Are there guidelines as far as how long after the surgery you should wait to fit these patients with the lenses?

McLaughlin: I think that varies with the surgeon and the confidence of the fitter. Since RK incisions don't go through the central zone of the cornea, those patients can be fitted a little bit sooner. Because PRK ablates the whole central cornea, those patients might not be stable as soon. However, if you present that to patients who are anxious to be fitted with a lens and let them know that the initial lens they get might not be the final lens, they'll appreciate that and take that into consideration.

I'm very conservative. I certainly yield to the surgeon. A lot of these people with RK are retreated and retreated. Usually you can get some stabilization in refractions in about 6 weeks. It takes a bit longer to stabilize with PRK.

PCON: Once these patients are fitted with their lenses, how often do you need to go back and check on them?

McLaughlin: We provide the normal follow-up care as we would with any patient: 1- to 2-week check, 1-month check, possibly a 3-month check. And usually, especially if it's an RK patient, I would not want them to go longer than 6 months without follow-up.

PCON: Is the post-refractive surgery lens fitting something you can accomplish in one visit, or does the patient need to come back several times?

McLaughlin: In this type of patient—keratoconus, post-corneal transplant or post-RK—I strongly recommend investing in the gas permeable warranty fee to allow them to modify the lens. With rigid lenses you can buy a warranty for $10 more per lens where there's an exchange. It's also really good to work with soft contact lenses that have some sort of guaranteed fit policy. Soft toric lenses, for example, allow you to change some lenses, which is important. In the long run it will save the doctor and the patient a lot of money. Also, that tells the patient that it's possible the first set of lenses might not be the final lenses. We present that right up front, and our fees reflect that it is a more challenged fitting that will take more chair time.

PCON: Do you routinely use corneal topography to fit these patients?

McLaughlin: That's an option if you have it. It's extremely useful, but not absolutely mandatory. It's no longer the way you learned to fit in school. Instead, it is trial and error. It's going to bring back the art of trial-fitting a patient.