In the face of unprecedented growth in the number of patients seeking refractive surgical procedures, it may be too easy to overlook the fact that not every patient who wants refractive surgery should get it. And those who do undergo a procedure should have realistic expectations about results.

In this article, we'll share with you how we save ourselves and our patients from the consequences of ill-advised ap-proaches or procedures that any of us might regret.

Contraindications

First, in some situations, it's unwise to perform refractive surgery at all. Patients with corneal ectasia are poor surgical candidates. Furthermore, some patients may only demonstrate ectatic signs topographically, thereby making it crucial to have preoperative corneal maps.

Patients with large astigmatic errors may also be poor candidates due to the probability of postoperative glare. This is particularly a factor with large scotopic pupillary diameters. You should advise these patients accordingly. And, obviously, active corneal disease -- corneal dystrophies and any condition that may affect refractive status (early cataract formation, uncontrolled diabetes) -- should give you pause.

You'll be considering other objective data as well. As far as age, we believe the ideal patient is at least 21 years old with a stable refractive history. In some cases, an 18-year-old with a 2-year history of stable refractions is a good candidate. But keep in mind that an 18-year-old may still have significant refractive changes to go through in his future. To gauge refractive stability, we perform a minimum of two refractions prior to surgery: one cycloplegic (wet) on evaluation day and one manifest (dry) on the day of surgery. We give more weight to the wet refraction, but if significant discrepancy exists between the two, we perform additional refractions.

A good guideline for acceptable stability is less than a -0.75D to -1.0D shift. Our accuracy of refraction is -0.25D to -0.5D, depending on the severity of ametropia. Hopefully, wavefront measurement technology will help us to improve our gold standard of refraction.

Care should be taken to ensure maximum consistency as you perform refractions. The cycloplegic drops, time of cycloplegia, vertex distance at the phoropter, method of subjective refinement (red/green test or three click blur out, for example) and light level in the examination room should be standardized. Consistent protocols minimize errors.

Assessing patient mindset

A patient's mindset is also a potential disqualifier. Each candidate must have a clear goal in mind as he's considering refractive surgery, or we don't proceed.

This is where accurate and careful consideration of the patient's social history is invaluable. Does this person like to play golf or do needlepoint? Does he scuba dive or play chess? The point is that a patient will be involved in a myriad of activities, many of which have different visual demands. The ability to accurately gauge what's most important to him will enable you to tailor your surgery to the individual, thereby creating better results.

We've found that patients are more satisfied with their experience if they have a clear, stated goal prior to surgery. Rather than accepting a general statement such as "I want to see better," it's more productive if you and your staff members draw out a more specific goal, such as "I want to see well enough to water ski without glasses."

Stating a well-defined, realistic goal will give the patient a better measurement of success. It's far more important that he accomplish his real-life goals than that he read some arbitrary line on the Snellen chart. Refractive surgery patients who achieve their stated goals are excited about their success and are excellent word-of-mouth practice builders.

Refractive surgery patients are, as a group, well-educated and informed. They generally research various procedures on their own, but they'll be very appreciative if you, as their surgeon, take the time to discuss the particular details of their case. Forging this connection with them makes it easier for you to develop a keen understanding of patients' goals and expectations so that you can properly advise and educate each one in his quest for better vision.

Creating realistic expectations

Part of that education involves making sure patient expectations are realistic by conveying the limitations of refractive surgery in each situation. Take, for example, a 48-year-old 2D myope who takes her spectacles off to read. This patient may be disappointed to find she can't read that way following surgery. She might be happier with a monovision-type correction, but monovision carries disadvantages as well, which you must explain to her. Decreased stereoacuity, reduced night vision and less depth of focus are common complaints. And don't forget your state's driving restrictions. Some states require 20/40 acuity in each eye for restriction-free licensure. Your monovision patient might be incensed at being ticketed if not forewarned about the possibility.

Given these disadvantages, in cases such as hers, we typically don't recommend monovision. Instead, we perform a modified monovision: We correct both eyes for distance, but leave the nondominant eye slightly myopic. The level of myopia depends on age, occupation, avocations and, of course, the patient's goals. This modified monovision is particularly effective with early presbyopes. Even if the slightly myopic eye isn't ideal for reading, it's usually sufficient for performing tasks such as seeing the food on a plate or looking in the mirror.

One way to educate patients on post-op vision is to demonstrate it with trial frames, but the phoropter isn't the real world. So we take that a step further, using contact lenses. We have surgery candidates come into the office, on a different morning than their pre-op evaluation, and we fit them with the contact lens power that will approximate their likely refractive status after surgery. Then, they spend the rest of the day following their normal routine with this correction.

This approach is extremely effective with emerging or early presbyopes, who don't yet fully understand what it will be like to have compromised near vision. Spending a day seeing how their near vision will change is also effective for patients considering an enhancement.

Patients younger than 40 won't likely benefit from such a demonstration, but we always educate these individuals regarding their future presbyopia. A 34-year-old 3D myope who reads four novels a week, for example, might not be happy considering life as a 44-year-old who must wear reading glasses. Going the extra mile in explaining to people what the future may bring will only serve both the doctor's and patient's best interests.

When a delay is necessary

In addition to patients who don't have clear goals or realistic expectations, contact lens wearers are another group who shouldn't be rushed into surgery. (See "Contact Lens Wear and Refractive Surgery," right.)

As a general guideline, we ask patients to discontinue wearing soft spherical contact lenses for at least 1 week prior to surgery. Toric soft lenses should be removed at least 2 weeks prior, and rigid gas permeable (RGP) lenses should be out for at least a month. It's frequently necessary for RGP wearers to stop wearing their lenses for more than a month to allow lens-induced corneal warpage to normalize.

We monitor RGP patients at 1-month intervals, performing cycloplegic refractions and corneal topographies at each visit. Once a stable refraction is achieved and corneal uniformity is maximized topographically, only then will we schedule the surgery.

Soft contact lens wearers who demonstrate any ocular surface irregularities on topography or at the slit lamp will be re-examined at 2- to 3-week intervals. In the interim, we ask that they discontinue contact lens wear and use artificial tears liberally.

It's also helpful to aggressively screen for and treat any signs of blepharitis or meibomitis -- in any patient. Healthy eyelid margins and an adequate tear film will increase patient comfort and vision postoperatively.

Solid advice for now and the future

Refractive surgery technology will eventually become a viable option for an even larger number of patients. But no matter how it evolves, proper patient selection and education will still be the only ways for your practice to continue to benefit while providing a truly positive life-changing experience for your patients.

Contact Lens Wear and Refractive Surgery

Long-term contact lens wear may change both the thickness and the shape of the cornea, possibly increasing the risk of complications after corneal refractive surgery, according to a study published in the journal Ophthalmology (Ophthalmology, 107(1):105-11 2000 Jan).

"We are certainly not suggesting people throw away their contact lenses," said one of the study's authors, Stephen C. Pflugfelder, M.D., of the Bascom Palmer Eye Institute, Miami. "What we are saying is that both surgeons and patients need to be aware of the potential risk factors and complications if the patients have worn contact lenses for a long period of time."

Sixty-four eyes of 35 patients who had worn contact lenses for more than 5 years were evaluated with the Orbscan Corneal Topography System and compared with 40 eyes of 20 non-contact-lens wearers. Contact lens wearers had worn lenses for an average of 13.45 � 6.42 years, and 21 of the subjects had worn rigid lenses for at least 10 years before switching to soft contact lenses.

The mean corneal thickness in the center and in eight peripheral areas measured in contact lens-wearing subjects was significantly reduced -- by 30 to 50 microns -- compared to normal subjects (P < .001 for central and peripheral sites). The corneal curvature and maximum and minimum keratometry readings were significantly steeper in eyes wearing contact lenses than normal eyes (P < .01).

Dr. Pflugfelder said some people with corneas that are too thin might not be considered good candidates for refractive surgery due to their risk of developing keratoconus.

Corneal stability after discontinuation of contact lens wear in preoperative refractive surgery candidates was examined in a study published in the Journal of Cataract and Refractive Surgery (J Cataract Refract Surg 1999 Aug;25(8):1080-6).

Topographic differences were analyzed in 136 non-contact lens wearers (NCLW) and 76 contact lens wearers (CLW) (18 rigid gas-permeable contact lenses [RGPCL], 58 soft contact lenses [SCL]) using EyeSys computerized videokeratography (CVK) after discontinuation of SCL wear for 2 weeks and RGPCL wear for 5 weeks.

The researchers (Budak K, Hamed AM, Friedman NJ, Koch DD, Cullen Eye institute, Baylor College of Medicine, Department of Ophthalmology, Houston) found no differences in CVK patterns between the NCLW and the CLW groups. There were no statistically significant differences between the two groups in topographic symmetry, asphericity, corneal uniformity index, predicted corneal acuity or irregular astigmatism. The dioptric range for the axial and the profile difference maps in the contact lens wearers was slightly lower than in the non-contact lens wearers.

The authors concluded that for patients whose manifest refraction and CVK maps were within 0.5D of earlier values, discontinuation of SCL wear for 2 weeks and RGPCL wear for 5 weeks was adequate for the cornea to return to its baseline topographic state.

Karl G. Stonecipher, M.D., is director of refractive surgery for Southeastern Laser and Refractive Center in Greensboro, N.C. You can contact him at (800) 632-0428 or stonenc@aol.com. Neil McMackin, O.D., is the clinical administrator of refractive surgery for Southeastern Eye Center.