Purpose: To evaluate the clinical tolerance of antiglaucoma eye drops with and without a preservative in routine practice.
Methods: A total of 125 ophthalmologists in private practice located throughout France examined altogether 919 glaucomatous patients treated with eye drops containing a preservative or not. For some patients the examination was repeated during a second visit. Functional signs as well as conjunctival and corneal examination results were recorded.
Results: The proportion of patients experiencing discomfort or pain during instillation was 58% for eye drops containing a preservative and 30% for eye drops with no preservative (p < 0.001). Moreover, the proportion of patients presenting at least one symptom of eye irritation (sensation of itching or burning, sensation of a foreign body in the eye, and flow of tears) was greater with preservative-containing eye drops (53% vs 34%; p < 0.001). The experience of discomfort during instillation was more often associated with problems later on. The patient's complaints were correlated with objective signs of conjunctival (conjunctival redness, conjunctival follicles), or corneal (superficial punctuate keratitis) damages. A higher proportion of patients treated with eye drops containing a preservative showed at least one conjunctival sign (52% vs 35%; p = 0.001) or superficial punctuate keratitis (12% vs 4%; p = 0.01). In 164 patients, whose treatment was changed from eye drops containing a preservative to eye drops with no preservative and who were examined a second time (mean interval between visits: 3.3 months) the frequency of all symptoms and objective signs fell by a factor of 3 to 4 (p < 0.001).
Conclusion: Patient complaints and objective damage to the ocular surface are more frequent among patients treated with eye drops containing a preservative. Ocular surface damage due to preservatives is partially reversible. Patient complaints should consequently be taken into account and preservative-free eye drops should be prescribed when ever possible.