DRY EYE DX AND TX
PREPARING THE DRY EYE FOR CONTACT LENS WEAR
WILLIAM TOWNSEND, OD, FAAO
When a patient presents to our office and says, “I have very dry eyes, but I want to wear contact lenses,” it typically means that we are in for a challenge. Unfortunately, this scenario is becoming increasingly common.
Dry eye occurs more frequently in contact lens wearers (Tyagi et al, 2012). Relying on self-reported symptoms of dry eye can be misleading; there is often poor correlation between symptoms and dry eye (Nichols JJ and Sinnott, 2006). Sullivan et al (2014) found that only 57% of individuals who have clinical signs of dry eye disease (DED) reported symptoms associated with a diagnosis of dry eye. It is in both the patient’s and practitioner’s best interest to determine whether DED is present prior to fitting contact lenses.
The mere presence of a contact lens on the eye may lead to dryness, as a contact lens segregates the tear film into pre- and post-lens layers (Tyagi et al, 2012). This alteration in the tear film increases evaporation and surface dewetting, ultimately resulting in increased tear film osmolality (Sullivan et al, 2014).
Machalińska et al (2015) reported that lens wear is an independent risk factor for meibomian gland dysfunction (MGD). They found that contact lens wear increased lid telangiectasia, orifice obstruction, and hyperemia and decreased meibomian gland secretion quality.
Arita et al (2009) evaluated the association between contact lens wear and loss of meibomian glands (meiboscore; i.e., a higher score relates to greater loss of glandular structure) in a study group of female and male lens wearers and a control group composed of non-lens wearers (mean age 31 years). They found that loss of meibomian glands in the study group was almost double that of the control group, and the average meiboscore in the lens-wearing group was similar to that of 60- to 69-year-old non-lens wearers. Loss of meibomian glands in the study group was proportional to the total duration of lens wear. These findings are relevant, given that MGD is well recognized as a very important, and perhaps the primary, underlying cause of DED (Nichols KK et al, 2011; Smith et al, 2007).
Many first-time lens wearers are children, and it might be easy to overlook the fact that dry eye can be a significant issue in this age group. Chen et al (2016) evaluated children aged 3 to 6 years of age for dry eye. In subjects who had seasonal and/or perennial allergic conjunctivitis, the incidence of dry eye was 97% compared to 22% in control subjects.
Visual displays are increasingly common in our society and may have an impact on the ocular surface, even in children. In a study involving 288 children, Moon et al (2014) reported that the daily duration of smartphone and video display terminal use was associated with increased risk of DED, but that the daily duration of computer and television use did not increase the risk of DED.
Each individual who presents for contact lens evaluation deserves a careful assessment for dry eye disease. This includes, but is not limited to, a dry eye-specific questionnaire; careful observation of the ocular surface and meibomian gland structure and function; and, if possible, tear film osmolarity evaluation. My next column will look at practical application of this information in preparing dry eye patients for contact lenses. CLS
For references, please visit www.clspectrum.com/references and click on document #251.
Dr. Townsend practices in Canyon, Texas, and is an adjunct professor at the University of Houston College of Optometry. He is treasurer of the Ocular Surface Society of Optometry and conducts research in ocular surface disease, lens care solutions, and medications. He is also a consultant or advisor to Alcon, Allergan, NovaBay, TearScience, TearLab, and ScienceBased Health. Contact him at email@example.com.