New technique to reduce systemic side effects of timolol eye drops: The tissue press method-Cross-over clinical trial.

IMPORTANCE: Nasolacrimal occlusion (NLO) is effective in reducing systemic absorption of eye drop medication but it is difficult and often performed poorly. We propose an alternative easier and equally effective technique. BACKGROUND: To test the effectiveness of systemic absorption, we evaluated plasma concentration and ocular effects after topically administered timolol and compared to NLO. DESIGN: Cross-over trial carried out in Capital Eye Specialist, Wellington. PARTICIPANTS: A total of 21 subjects over 18 years without contraindications for topical beta-blocker medication and not using systemic beta-blockers. METHODS: During three clinic visits separated by at least one week, alternative approaches to reduce systemic eye drop absorption were tested. These were: (a) nasolacrimal (punctal) occlusion for 5 min, (b) tissue press method or (c) no intervention. Timolol plasma levels were measured 1 h after drop application. At each visit, baseline measurement of blood pressure, heart rate and intraocular pressure (IOP) were performed, and repeated 1 h after timolol 0.5% eye drop application. MAIN OUTCOME MEASURES: Comparison of timolol plasma concentration after each intervention. Secondary outcome measurements included effects on blood pressure, heart rate and IOP. RESULTS: Plasma timolol concentrations after tissue press method and NLO were significantly lower than those without intervention. Comparing tissue press method to NLO, there were no significant differences in plasma levels of timolol, blood pressure, heart rate or IOP. CONCLUSION AND RELEVANCE: The tissue press method is equally effective as NLO in reducing systemic absorption of timolol. It is also easier and faster to administer.