Procedure, healing guide dispensing in postrefractive surgery patients

Issue: July 1999

Practitioners must consider many variables when prescribing contact lenses and spectacles for the postrefractive surgery patient. Whether the patient has had radial keratotomy (RK), photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) as well as an individual’s age and rate of healing will determine how and when that person should be fitted for either contacts or glasses. The specific procedure also may determine how crucial a corneal topographer is in fitting a patient for contact lenses.

Loretta Szczotka, OD, MS, director of the contact lens service at University Hospitals of Cleveland, says that the classic three healing responses for PRK patients are a good place to start. Type 1 is the normal healing stage. With type 2 healing, the patient is hyperopic. Type 3 refers to the aggressive healer, who regresses to myopia. Dr. Szczotka said that type 1 patients may be fitted for corrective lenses – if necessary — about 9 months postoperatively. “For type 2 PRK patients, we fit contact lenses very soon, approximately 3 months after surgery, because we actually want to stimulate regression,” she said. “In a type 3 patient, we think that maybe too much stimulation caused the regression, so that patient is absolutely contraindicated for contact lenses for up to 2 years after surgery.”

Classic healing responses have not yet been formulated for LASIK patients, Dr. Szczotka said. Most patients are fit with contact lenses between 2 and 3 months following surgery, she said, depending on the condition of the flap. “We’re concerned with the flap not moving and dehiscing, and that’s really the only reason for waiting,” she said.

Vision fluctuation

While the results of RK can vary extremely from one patient to another, PRK and LASIK recipients typically have a positive initial response and tend to stabilize faster, said Keith Harrison, optician and certified lens fitter at Toronto Western Hospital. “With a person who has had PRK, there will be significant improvement in vision in the first few days, and the cornea will look fairly clear,” he said. “It’s not uncommon to see a slight increase of haze in the cornea at 2 to 4 weeks, which then clears up. In that situation, you would probably hold off on prescribing spectacles, unless the person is not functional without them.”

Mr. Harrison agreed with Dr. Szczotka that after LASIK, as long as the flap reattaches uniformly, results are usually positive and vision stabilizes fairly quickly. “If it doesn’t, then they may have a little bit of wrinkling, and that may give them a little residual astigmatism, which may require an enhancement,” he said. “With time, that may reduce as well.”

Dr. Szczotka said that while she tries to stall patients who are impatient for corrective lenses until a sufficient amount of time has elapsed, she will prescribe lenses, with a word of caution, if someone is adamant about it. “You have to warn the patient that he or she might be spending a lot of money changing these lenses frequently,” she said. “I tell patients that they’re still in the healing phase, and the cost of the lenses would be their own expense. They usually agree to wait it out.”

Readers: short-term solution?

Due to the fluctuation in vision that usually occurs in the first few months following refractive surgery, some patients may opt for readers, or ready-made glasses available in drugstores. Mr. Harrison said that while they may serve a purpose initially, patients should know that these glasses should have a short life and should not replace a pair prescribed by their practitioner and designed specifically for them.

“People don’t realize that the PDs [pupillary distances] in ready-made readers are not set for individual patients,” he said. “With the higher powers, you are inducing prism. If you have +3.00 readers, which have a PD of 66 mm set in them, and you have a person who has a PD of 60, you’ve got well over 1 D of prism right off the bat. Then, people end up with eyestrain and headaches and wonder why. You have to explain to patients that it is a short-term solution and that, at some point, they should have a pair of spectacles properly made for them.”

Mr. Harrison said that some practitioners find that “pinhole” eyeglasses, glasses with black sunglass-type lenses with a number of pinholes, are sometimes helpful for patients having difficulties while healing. “As you move your eye to different positions, you’re seeing through these pinholes,” he said. “It will eliminate peripheral light and give good central vision. So, for the patient having a great deal of problems in the healing process, I’ve seen that used for the short-term to allow the person to function.”

Using a corneal topographer

After a patient undergoes refractive surgery, no matter what method, Dr. Szczotka said that she will use a corneal topographer to aid in fitting for contact lenses. “It assesses the degree of irregular astigmatism, which helps assess patients’ limitations,” she said. “I can better comprehend what patients are telling me in terms of their poor vision. The degree of irregularity on the map quantitates exactly how symptomatic they are.”

Based on the irregularities the topography may indicate, Dr. Szczotka said, a determination can be made as to whether to prescribe a soft lens or a rigid gas-permeable (RGP) lens. She said that mild irregularity may mean that a soft lens geared toward the postrefractive surgery patient may be prescribed. The amount of astigmatism it will correct is limited, however. “If there’s more, then the patient will need an RGP lens,” she said. “Then, the topographer also helps me fit the lens by specifically choosing areas on the map for initial base curve selection for the lenses. It’s very valuable.”

Mr. Harrison said that corneal topography comes in most handy for the postrefractive RK patient. However, he noted, the two-dimensional scan can only provide information to a point. “We have to bear in mind that corneal topography is giving us a static amount of information,” he said. “We’re going to put a contact lens in that eye, a three-dimensional environment that is dynamic as well. We’re applying one surface to another with an eyelid passing over it to make that lens shift and move 10,000 times a day. So, unfortunately, as much science as we’ve been able to apply, there’s still a great deal of artwork to it.”

With that in mind, making sure that the technician is experienced in fitting this type of patient will generate the best results. “It certainly gives you a much better starting point and much more insight as to why certain things happen when you have the lens on, but it really comes down to Contact Lens Fitting 101,” he said.

Who needs correction?

While some refractive surgery patients may opt for glasses to enhance nighttime driving, Dr. Szczotka said she finds that most do not require vision correction for their regular daily activities. “Only 1% to 2% are having problems where they need a contact lens, and the biggest problem would be irregular astigmatism,” she said. “If they’re just nearsighted, or a little farsighted, then they normally just proceed with enhancements or they live with that little amount of less-than-perfect vision. When they come for contacts, they’re almost always here because they have irregular astigmatism, which cannot be corrected with glasses.”

It may be difficult to determine just how many patients shed their glasses or contacts postop, said Mr. Harrison, depending on at what point following surgery a patient’s vision is evaluated. Even then, he said, the previous corrective lenses may be disposed of, in favor of a different pair with a newer, if less severe, prescription. “I’ve seen ads stating that 90% of refractive surgery patients throw away their glasses,” he said. “How about 100%? If you’ve done refractive surgery, their glasses are no good to them anymore. Refractive surgery has to be considered for what it is: myopia, hyperopia or astigmatic reduction. If and when you can eliminate it, that’s outstanding, but it is a procedure to reduce your dependence on glasses or contacts. Patients need to bear that in mind.”

Provide qualified optical service

Some practitioners may decide to have ready-made spectacles available on-site for patients to purchase immediately postop should they require it. Whether a doctor decides to take this route or not, Mr. Harrison recommended a licensed optician or similarly qualified dispenser for proper fitting and thorough patient education. “Why would you give someone the best surgical care and not the best optical care?” he said.

For Your Information:

Loretta Szczotka, OD, MS, FAAO, is the director of the contact lens service at University Hospitals of Cleveland and assistant professor at Case Western Reserve University Department of Ophthalmology and practices at University Ophthalmologists Inc. She may be reached at 11100 Euclid Ave., Ste. 3200, Cleveland, OH 44106; (216) 844-3609; fax: (216) 844-7117. Dr. Szczotka has no direct financial interest in the products mentioned in this article, nor is she a paid consultant for any companies mentioned.

Keith Harrison, an optician and certified contact lens fitter, is President of Harrison Optical Services, which provides ophthalmic services for Toronto Western Hospital. He may be reached at 399 Bathurst St., Room EC7-014, Toronto, Ontario, Canada M5T2S8; (416) 603-5474; fax: (416) 603-5114. Mr. Harrison has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.