advertisement
Abstract #9898 Published in IGR 5-3
Comparison of the short-term effects on the human corneal surface of topical timolol maleate with and without benzalkonium chloride
Ishibashi T; Yokoi N; Kinoshita SJournal of Glaucoma 2003; 12: 486-490
PURPOSE: To compare the short-term effects of timolol maleate with and without preservative (0.005% benzalkonium chloride) on pre-corneal tear film stability and corneal epithelial barrier function. SUBJECTS AND METHODS: The study population consisted of 20 healthy volunteers. To obtain baseline values, seven days before the experiment the non-invasive breakup time of the pre-corneal tear film was measured using a tear specular microscope; corneal fluorescein uptake was measured with a fluorophotometer. Unpreserved or preserved 0.5% timolol was applied to one eye; the contralateral eye was exposed to the other drug. At 30 minutes after instillation, the pre-study tests were repeated. RESULTS: Preserved timolol did, while unpreserved timolol did not, significantly reduce the non-invasive breakup time from the baseline values (baseline and post-exposure values 11.4 and 6.8 seconds, respectively, p = 0.008 for preserved timolol, and 11.7 versus 11.0 seconds, p = 0.55 for unpreserved timolol). On the other hand, corneal fluorescein uptake was significantly increased upon exposure to either preserved or unpreserved timolol (baseline and post-exposure values 37.5 and 82.0 ng/ml, p < 0.001 for preserved timolol, and 35.4 versus 57.6 ng/ml, p < 0.001 for unpreserved timolol). Preserved timolol exerted the greater effect (p = 0.028). CONCLUSIONS: Exposure to preserved timolol resulted in significant instability in the pre-corneal tear film. Moreover, it disrupted the corneal epithelial barrier function to a greater degree than unpreserved timolol. The elimination of preservatives may be desirable in efforts to protect the integrity of the corneal surface and its interaction with the tear film.
Dr. T. Ishibashi, Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan. tishibas@ophth.kpu-m.ac.jp
Classification:
11.3.4 Betablocker (Part of: 11 Medical treatment > 11.3 Adrenergic drugs)
