discovering dry eye
Defining Successful Lens Wear
BY KELLY K. NICHOLS, OD, MPH, PHD
Webster's Dictionary defines success as "the attainment of a favorable or desired outcome." As
eyecare professionals, it's our job to create the condition of "successful wear"
for our contact lens patients. Our training makes this possible most of the time, but occasionally, because of patient factors, physiology and optics, we fail.
Your View or Mine?
A patient's perception and definition of "successful wear" may differ from our professional opinion of what that term means. In contact lens wear, "success" is closely related to a patient's expectations. Sarver and Harris (1971) defined the criteria of a successful contact lens patient in five categories:
1. Wearing time -- the ability to wear lenses regularly and continually for a minimum of eight hours
2. Comfort -- the patient may experience no more than a slight awareness, photophobia or foreign body sensation
3. Vision -- the visual acuity should fall within one Snellen line of best spectacle corrected visual acuity with no significant blur or flare
4. Ocular tissue change -- the ocular surface should remain free of significant disturbances, with only slight staining or curvature change
5. Normal patient appearance -- no squinting, head alteration or conjunctival redness should occur.
TABLE 1 OSU Lens Wear Survey
1. In your own words, how would you define
"successful wear" of a refractive correction?
2. Are you "successful" in your own correction
3. What is your most "successful" mode of correction?
Putting Success to the Test
To get a better idea of "successful wear," I informally surveyed the faculty and staff at The Ohio State University College of Optometry (OSU) with three questions about successful wear (Table 1). (The questions weren't specific to contact lens wear.)
The following statement embodies most of the comments I received about the definition (question 1): "Successful wear is the ability to perform desired visual tasks comfortably every day." In addition, many felt that they should experience "no noticeable negative intrusion of the device itself." Especially with regard to contact lens correction, many reported that "no compromise to the health of the eye," and no "awareness" or "thought that goes into wearing a correction," should occur. The most frequent responses included the terms "comfortable" and "great vision." All of the respondents reported that they're successful with the correction(s) they wear, and about 30 percent wear contact lenses.
Are Sarver and Harris Current?
Occasionally, a "successful" patient doesn't meet the Sarver and Harris definition. This applies specifically to dry eye patients who wear contact lenses. A dry eye patient who can wear a soft contact lens comfortably for two hours while exercising could consider that a success. We could also view increasing comfortable wearing time from four hours to eight hours by using adequate lubrication or other medical management as a success.
The underlying important characteristic is appropriate patient expectations. This was clear in the OSU surveys: The respondents all reported success, yet many used several "combinations" of correction to reach that perceived endpoint. I'm not surprised that the faculty and staff re-created the classic Sarver and Harris definition -- it's important to remember that true "success" may lie in each patient's eyes.
To obtain references for this article, please visit
http://www.clspectrum.com/references.asp and click on document #110.
Dr. Nichols is an associate professor at The Ohio State University College of Optometry in the area of dry eye research.
Contact Lens Spectrum, Issue: December 2004