Looking Back: Contact Lenses and Dry Eye
BY KELLY K. NICHOLS, OD, MPH, PHD
In celebration of Contact Lens Spectrum's anniversary, it's appropriate to look back on the history of dry eye and also to look forward to where we're heading in puzzling out this condition.
In 1986 several articles first linked the previously separate issues of contact lenses and dry eye. Farris (1986) and Lemp (1986) discussed the concept of lens-related dry eye in two highly cited articles. Interestingly, while significant advances have occurred in the field of dry eye and ocular surface disease, the etiology of contact lens-related dry eye is largely unknown, even 20 years later.
Diagnosing Lens Patients
The same year, McMonnies published his first report of the survey
now known as McMonnies Dry Eye questionnaire (McMonnies, 1986). The scoring mechanism
of the survey gives more weight to some questions, one of which is whether a patient
wears contact lenses. Additional questions about medication use, frequency of symptoms,
mental stimuli and systemic history are designed to aid in diagnosing dry eye.
Brennan and Efron (1989) and Golding et al (1990) helped establish a significant focus on symptoms with contact lens wear. In particular, they discussed the concept of tear film stability over a contact lens and its relation to symptomatology, an idea ahead of its time.
The Tests We Use
Cho et al (1993) performed a significant amount of work to evaluate the tests for diagnosing dry eye, and the fields of contact lenses and dry eye merged. In 1995, the report of the NEI/Industry workshop on clinical trials in dry eye listed contact lenses as a sub-category of evaporative dry eye in the overall dry eye schematic (Lemp, 1995). This document has since become accepted as a landmark in defining dry eye, and the concepts discussed became the roadmap for a decade's worth of dry eye research and exploration.
In the late 1990s, increased interest in the symptomatology of contact lens patients resulted in several dry eye surveys, including the CANDEES survey (Doughty et al, 1997) and the Contact Lens Dry Eye Questionnaire (Begley et al, 2000), the findings of which supported frequent reports of dryness and irritation symptoms in contact lens patients.
The term 'contact lens-related dry eye' has evolved over the past three to four years to describe patients who experience dry eye symptoms only during contact lens wear.
Where we have no consensus is regarding patients who have episodic
dry eye (perhaps under extreme environmental conditions) that worsens with lens
wear. Is this dry eye or lens-related dry eye? Management strategies in either case
include contact lens wear and care regimen overview, and a step-wise lubricant and
Advances in lens materials and design, lens solutions and rewetting drops, and dry eye treatment have changed the contact lens landscape. To fully understand contact lens-related dry eye, we must understand tear film/lens interactions, deposition (properties, quantity, location), physiological changes to the ocular surface and the link with symptoms. This will require multidisciplinary studies involving new technology such as interferometry, mass spectrometry and osmolarity (Nichols and Sinnott, 2006) in addition to new tests that we have yet to discover.
To obtain references, visit www.clspectrum.com/references.asp and click on document #127.
Dr. Nichols is an associate professor at The Ohio State University College of Optometry in the area of dry eye research.