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Dry Eye Common in Contact Lens Wearers

Contact lens wearers commonly report a sensation of 'dryness' - a symptom that often results in reduced wear time or discontinued use. In most cases of contact lens-induced dry eye, objective signs are lacking and a diagnosis is based on symptoms alone. However, it has been demonstrated that intolerant contact lens wearers show significantly reduced tear stability and volume compared to successful wearers.

A variety of conventional strategies have been employed to alleviate contact lens-induced dry eye including use of artificial tears, changing lens parameters, or preserving tears with punctal plugs. However, novel treatment strategies using anti-inflammatory or immune modulating agents may also be effective. A recent pilot study, for example, offers evidence that cyclosporine may be beneficial in contact lens intolerant patients (1).

Oral GLA of Benefit in Inflammatory Dry Eye

Another more 'natural' approach involves the use of supplemental gamma-linolenic acid (GLA), an omega-6 fatty acid with anti-inflammatory properties found in oils derived from black currant seeds and the evening primrose plant. Several small trials testing GLA and linoleic (LA) oil in dry eye syndrome with an inflammatory component report reduced ocular surface inflammation and symptom improvement (2,3). These beneficial findings led researchers to examine the effects of GLA in contact-related dry eye patients (4).

Study Design and Methods

In this randomized, double-blind controlled trial, 76 female soft contact lens wearers with documented dry eye or borderline dry eye (McMonnies score =10), were treated for 6 months with GLA (300 mg daily) from evening primrose oil (EPO) or placebo (olive oil).

Participants were examined at 3 time points: baseline and at 3 and 6 months. At each exam, subjects answered a questionnaire relating to lens comfort and dry eye symptoms, and underwent a series of tests of tear film characteristics (tear meniscus height, break-up time), meibomian gland function (lipid layer thickness and quality), and ocular surface parameters (hyperaemia and staining).

Results

The GLA group showed a significant improvement in the specific symptom of 'dryness' at 3 and 6 months (p <0.01) as well as significant improvement in overall lens comfort at 6 months (p<0.01). Tear meniscus height was increased in the GLA group at 6 months relative to baseline (p<0.01), although all other objective signs were unchanged (See figures 2 and 4).

Comments

This study provides evidence for a beneficial effect of oral GLA in alleviating symptoms and improving overall lens comfort in patients suffering from contact lens associated dry eye. According to the authors, this may be via a reduction in ocular surface inflammation that has been previously documented in contact lens wearers. An effect on tear secretion could also be a contributing factor. The authors indicate that "future studies will investigate the efficacy of a combined preparation (GLA, EPA and DHA), since it is likely that omega-3 fatty acids could act synergistically with omega-6 to enhance the therapeutic effect of each fatty acid".

References

1. Hom MM. Use of cyclosporine 0.05% ophthalmic emulsion for contact lens intolerant patients. Eye Contact Lens 32:109-11, 2006.
2. Barabino, M et al. Systemic linoleic and gamma-linolenic acid therapy in dry eye syndrome with an inflammatory component. Cornea 22:97-101, 2003.
3. Aragona P, et al. Systemic omega-6 essential fatty acid treatment and PGE1 tear content in Sjögren's syndrome patients. Invest Ophthalmol Vis Sci 46:4474-9, 2005
4. Kokke KH, et al. Oral omega-6 essential fatty acid treatment in contact lens associated dry eye. Contact Lens Anterior Eye 31:141-6, 2008.