Nancy Keir is Senior Clinical Manager, New Technologies, Research & Development at CooperVision.
The “definition and classification” committee of the Tear Film and Ocular Surface Society (TFOS) international workshop on contact lens discomfort noted that although terms like “contact lens-induced dry eye” link contact lens dryness to dry eye, there is no evidence these two conditions are associated.1 However, contact lens dryness and aspects of dry eye have a lot in common, such as the lack of correlation between signs and symptoms and the fact that they are both complex and multifactorial. A better understanding of the differences between individuals who experience dryness with contact lens wear and individuals who experience dryness without contact lens wear may be helpful to determine whether there are patterns to help explain this symptom. In this review, Nancy Keir revisits a 2006 article exploring dryness symptoms with and without contact lens wear:
Chalmers RL, Begley CG. Dryness symptoms among an unselected clinical population with and without contact lens wear. Contact Lens & Anterior Eye 2006;29:25-30.
The authors sought to determine whether demographic factors associated with dryness symptoms were similar between contact lens wearers and non-lens wearers. This was achieved by conducting a retrospective review of responses to two questionnaires: the Dry eye Questionnaire (DEQ) and the Contact Lens Dry Eye Questionnaire (CLDEQ). One of these questionnaires was completed by 1054 patients who had presented for eye care in a multi-center cross-sectional study.2 Of the 1054 patients, 367 were contact lens wearers and completed the CLDEQ, while 687 (167 former contact lens wearers and 520 non-lens wearers ) completed the DEQ. Both questionnaires measure the frequency and intensity of various symptoms at three times of day. Appropriate statistical tests were chosen and included Pearson’s Chi-square, t-tests and Spearman’s rho. Missing responses were handled by adjusting the denominator accordingly.
Study populations and eye conditions
With respect to the study populations and eye conditions, the current contact lens wearers were significantly younger and consisted of more females than the former contact lens wearers or non-lens wearers.
Prevalence of ocular symptoms with and without contact lens wear
Current contact lens wearers had fewer reports of dry eye and blepharitis. Results for the prevalence of ocular symptoms with and without contact lens wear indicated that among the current contact lens wearers, the prevalence of symptoms was higher with lens wear than without. For instance, the prevalence of intense late day dryness was 28.5% with lens wear and only 1.5% without lens wear.
Factors associated with ocular surface dryness
Despite a greater prevalence of occupational computer use for current and former contact lens wearers than for non-lens wearers, computer use did not correlate significantly with the frequency or intensity of dryness symptoms. Regardless of lens wear or no lens wear there was a significant, inverse correlation between age and dryness symptoms, with younger patients reporting more symptoms. Female gender was correlated with frequency and intensity of dryness symptoms in the non-lens wearers, however there was no significant correlation in the current or former contact lens wearers.
Former contact lens wearers
For the former contact lens wearers, the primary reason for discontinuation of contact lens wear was cited to be “my eyes felt dry”, followed by “the lenses became more uncomfortable later in the day” and “the lenses felt scratchy and irritating”. The proportion in this group who gave a positive response to the question “do you have dry eyes?” was significantly higher than for current wearers or non-lens wearers.
Methods of coping with contact lens dryness
The most frequent self-treatment used by current contact lens wearers to cope with their contact lens dryness was lens removal. This was also reported to be the most successful coping activity, with lens rewetting drops and artificial tears both being less effective.
Summary: Important findings
While the authors state that a study of this nature is unable to determine causal relationships, the comparisons made in this study suggest that:
- Contact lens dryness is a unique, temporary condition with a distinct pattern different to dryness in non-lens wearers,
- Contact lens dryness is not associated with gender,
- The most effective coping mechanism is lens removal, and
- The frequency of symptoms and intensity of late day symptoms is greater in lens wearers than non-lens wearers.
1. Nichols KK, Redfern RL, Jacob JT, et al. The TFOS International Workshop on Contact Lens Discomfort: Report of the Definition and Classification Subcommittee. Invest Opthalmol Vis Sci 2013;54:TFOS14-TFOS19.