dry eye

Seeking Clarity

Fluctuating vision as a diagnostic marker for dry eye disease

KELLY K. NICHOLS, O.D., M.P.H., PH.D.

In the 2007 Report of the International Dry Eye Workshop (DEWS), “changing or fluctuating vision” is mentioned as a dry eye disease (DED) symptom: DED patients sometimes report having to blink a lot for clear vision when watching TV or doing computer work, especially late in the day.

Clinically, we might expect that high-contrast, black-on-white visual acuity would either be unaffected or minimally affected by DED. Surprisingly, studies on DED’s impact on high-contrast visual acuity, low-contrast visual acuity or contrast sensitivity are sparse. That said, I don’t think these measures are sensitive enough to detect a DED patient’s vision fluctuation: DED patients, if given long enough, can clear their vision by frequent blinking, and can, thus, “squeak out” good high-contrast visual acuity.

So, how can we determine whether fluctuating vision is a sign of DED and its severity?

1 Ask vision-related quality-of-life questions.

Ask the following questions:

1. How is your vision during TV use? Are your eyes dry, and do you find yourself blinking, rubbing and/or closing your eyes briefly for clarity? If so, are these symptoms worse at night?

2. How is your vision during computer use? Are your eyes dry, and do you find yourself blinking, rubbing and/or closing your eyes briefly for clarity? If so, are these symptoms worse at night?

3. How is your night-driving vision? Are your eyes dry, and do you find yourself blinking, rubbing and/or closing your eyes briefly for clarity?

These questions elicit “quality-of-vision” information related to DED, but you must listen hard to determine the severity of the patient’s fluctuating vision. A practitioner’s estimation of dry eye’s impact on a patient’s quality of life is significantly underestimated compared with how the patient perceives his/her dry eye.¹

2 Stay abreast of vision assessment technology.

It won’t be long before subtle changes in tear film stability, visual acuity and high-order aberrations can be measured in patients who have dry eye symptoms. (Late-day appointments may be valuable, as tear film stability in DED patients is more likely to change as the day progresses.)

Measures of “light scatter” can be reduced with artificial tear use in dry eye, a recent clinical study reveals.² While “light scatter” isn’t typically measured in-office, I expect this will be used to measure the severity of fluctuating vision, as we begin to understand how the DED subclasses can be assessed with aberrometry and associated technology.

Take home lesson

A clear, stable tear film is the eye’s major refracting surface. So, it makes sense that DED causes fluctuating vision. To determine whether patients with unexplained visual complaints have DED and the complaints’ severity, follow the tips above. OM

1. Chalmers RL, Begley CG, Edrington T, et al. The agreement between self-assessment and clinician assessment of dry eye severity. Cornea. 2005 Oct;24(7):804-10.

2. Diaz-Valle D, Arriola-Villalobos P, Garcia-Vidal DE, et al. Effect of lubricating eyedrops on ocular light scattering as a measure of vision quality in patients with dry eye. J Cataract Refract Surg. 2012 Jul;38(7):1192-7. doi: 10.1016/j. jcrs.2012.02.040.

DR. NICHOLS IS A FOUNDATION FOR EDUCATION AND RESEARCH IN VISION (FERV) PROFESSOR AT THE UNIVERSITY OF HOUSTON COLLEGE OF OPTOMETRY. SHE LECTURES AND WRITES EXTENSIVELY ON OCULAR SURFACE DISEASE AND HAS INDUSTRY AND NIH FUNDING TO STUDY DRY EYE. SHE IS ON THE GOVERNING BOARDS OF THE TEAR FILM AND OCULAR SURFACE SOCIETY OF OPTOMETRY AND IS A PAID CONSULTANT TO ALCON, ALLERGAN, INSPIRE AND PFIZER. E-MAIL HER AT KNICHOLS@OPTOMETRY.UH.EDU, OR SEND COMMENTS TO OPTOMETRICMANAGEMENT@GMAIL.COM.