Abstract: Glaucoma and higher dry eye incidence.

I don't get it. If you had access to all the medication information for these patients, how could you do a study like this and NOT report the percentages using glaucoma meds preserved with BAK - since we already pretty much know that's the link between glaucoma patients and dry eye?

Characteristics of respondents with glaucoma and dry eye in a national panel survey.
Clin Ophthalmol. 2009;3:645-50. Epub 2009 Nov 16.
Schmier JK, Covert DW.
Exponent Inc., Alexandria, VA, USA;

BACKGROUND: There is an increasing body of evidence strongly suggesting that glaucoma medications may contribute to ocular surface disease and development of dry eye.

OBJECTIVE: To identify glaucoma patients with dry eye, using a nationally representative sample, and to compare clinical and treatment characteristics with controls without dry eye.

METHODS: Patients taking intraocular pressure-lowering medications were identified from the Medical Expenditure Panel Survey. A matched cohort without glaucoma served as controls. Dry eye was identified by diagnosis or use of prescription or over-the-counter medications. Demographic and clinical characteristics and medication use patterns were compared.

RESULTS: The analysis identified 629 respondents with glaucoma and 6,934 controls without glaucoma. Dry eye was more common among glaucoma respondents than nonglaucoma controls (16.5% vs 5.6%, P < 0.0001). There was a nonsignificant trend for respondents with dry eye to report higher rates of glaucoma adjunctive therapy use compared to those without dry eye (44.2% vs 35.0%, P < 0.076). Prostaglandin analogs were the most common glaucoma medication.

CONCLUSIONS: This analysis found that the rate of dry eye was higher in patients with glaucoma than in controls. The use of glaucoma adjunctive therapies may increase the rate of dry eye in glaucoma patients.