Article Date: 7/1/2004

orthokeratology today
Coping With the Six-Month Syndrome

Establishing a schedule for follow-up visits is important with any type of contact lens wear, but it's especially important with orthokeratology. You should see ortho-k patients regularly to ensure that complications are minimal and that patients are compliant with their wear and care regimens.

The "six-month syndrome," which I'll explain here, is a perfect example of why you need to schedule regular visits for these patients.

Observing the Phenomenon

When I first started fitting ortho-k lenses, I noted a curious phenomenon that other practitioners later confirmed. Patients would do well until their six-month visit, at which point they would report that their vision had degraded a little during the previous few weeks. Their uncorrected acuity was usually a few letters to a line worse than previously, and sometimes we couldn't achieve a full 20/20 with correction.

Biomicroscopy usually revealed no corneal signs such as staining or edema. Corneal topography, however, usually showed some degree of central irregularity compared to previous maps (see the six-month [lower right] map in Figure 1). What was the cause of this irregularity, and how could we fix it?


Figure 1. Corneal topography reveals central irregularity after six months of ortho-k lens wear.

Clearing Things Up

When I inspected the patients' contact lenses, almost all of them had some back surface deposits visible with the slit lamp. Because I could find no other cause, I assumed that the deposits might be causing the topography irregularity and decreased daytime acuity.

I cleaned each patient's lenses with heavy duty lab cleaners (such as Boston Cleaning Polish [Polymer Technology] and Fluorosolve [Paragon Vision Sciences, Inc.]) to remove the deposits and asked the patients to return for follow up in week or so. The cleaning usually resolved the problem and improved their acuity. If it didn't, then I ordered a clean, new pair of lenses.

Other reasons may cause a patient to experience reduced acuity during treatment, so make sure you explore all possibilities. But a thorough cleaning usually takes care of it.

Let me communicate a note of caution: I don't recommend polishing the back surface of ortho-k lenses. Doing so can alter the parameters, resulting in a change in treatment effect.

Educating Patients

Review lens cleaning steps with your patients to make sure that they understand your care instructions, but know that even this may not help -- I've found that even seemingly compliant patients have experienced the "six-month syndrome."

Because of this problem, I generally recommend that patients use a daily cleaner or daily enzyme rather than a multipurpose GP solution alone when caring for their ortho-k lenses.

Dr. Jackson is an assistant professor at Southern College of Optometry where he works in the Advanced Contact Lens Service, teaches courses in contact lenses and performs clinical research.


Contact Lens Spectrum, Issue: July 2004