discovering dry eye
Contact Lenses and Dry Eyes
BY BARBARA CAFFERY, OD, MS, FAAO
Studies show that up to 50 percent of soft lens wearers complain of dryness when wearing lenses. If we would ask about dryness symptoms in the evening, it is likely that the percentage of patients with problems would increase.
Some patients are simply dry-eyed to begin with, so look for signs of dryness in the pre-fit examination. The more normal presentation comes from long-standing lens wearers who develop these symptoms over time. Age is one risk factor for dry eye disease, so some patients have simply crossed over the dryness threshold, and their lenses exaggerate the problem. Give these patients a full tear film workup as well.
Following are my suggestions for resolving lens-related dry eye symptoms:
1. Assess the fit. Does the lens move enough even at the end of the day? Is it well centered?
2. Assess the lens surface. Does the tear film flow easily? Is the surface soiled?
3. Look for cracks and faults in the lens.
4. Flip the lids and look for signs of inflammation.
5. Decide if the solutions are appropriate and if the patient is following the care instructions properly.
6. Take the lenses off and do a dry eye workup. Essential testing includes Schirmer, fluorescein staining (looking for lens edge impressions and corneal staining), BUT, lid assessment.
7. Note the blink rate and completeness of blink.
Treat ocular surface problems first. The easiest to solve are blepharitis and meibomian gland dysfunction. Teach patients how to do lid scrubs and hot soaks. Healthy lids really do make eyes feel better. Check patients in two weeks to determine if they are following instructions and getting results. Surface epithelial cells may be fatigued from overwear. Ask patients to remove lenses earlier and to use lubricants in the evening to restore ocular surfaces.
If lens fit or condition is questionable, fix this next. For spherical patients, switch them to a one-day regimen. A fresh lens daily will not be coated or damaged. Within the daily disposable modality there are several materials to try, which may also make a difference.
If daily disposability does not solve the problem, consider changing material. Try Extreme H2O (Hydrogel Corp.) or Proclear Compatibles (CooperVision) lenses. These lenses are marketed for dry eye patients and may make a difference in comfort and wear time. I've found that silicone hydrogel materials make a positive difference in some patients who have dry eye symptoms. Different materials make inexplicable differences in the symptoms of some patients.
Next, think about available solutions and drops. I like to switch patients to a non-preserved system like AOSept (CIBA Vision). This requires more effort than a one-bottle system, but it ensures that the lens goes into the eye with no chemical preservatives. If this solution does not reduce dryness symptoms, then solutions are not the issue. For one-step systems, change the solutions to change the preservatives. Complete (Advanced Medical Optics) solution has been shown to reduce dryness symptoms clinically.
Eyedrops may help patients get through the day. The new Clerz Plus (Alcon) drop is reported to reduce lens protein deposits and may be worth trying.
Finally, the blink can be the issue. Patients who spend a good deal of time at the computer can have a very low blink rate. Ask these patients to consciously blink on the half hour. Stand up from the desk, look out the window to reduce accommodative fatigue and blink, blink, blink.
Dr. Caffery has practiced optometry in Toronto, Canada, in a group setting dedicated to contact lens and tear film research since 1977.