Is Homatropine 5% effective in reducing pain associated with corneal abrasion when compared with placebo? A randomized controlled trial

Abstract

Objective: To compare the change in visual analogue scale (VAS) pain ratings over 24h following mechanical corneal abrasion between patients receiving sixth hourly drops of either 5% homatropine or placebo.Methods: A triple blind randomized controlled trial was conducted on a convenience sample of eligible consenting adults who were randomized to receive either sixth hourly 5% homatropine (active) or 0.5% hypromellose (placebo) eye drops. VAS pain ratings were performed at 0, 6, 12, 18 and 24h whereas the study drug was instilled at 0, 6, 12 and 18h. The primary outcome was attainment of a clinically significant reduction in pain on the VAS (>20mm decrease) from enrolment to each time point.Results: There were no significant differences in baseline variables or VAS pain ratings at any time point between those in the homatropine (n= 20) and placebo (n= 20) groups. The percentages of patients reporting a >20mm VAS decrease at 12h were 50% (95% CI -27.2-72.8) and 60% (95% CI -36.1-80.9) for the homatropine and placebo groups, respectively.Conclusion: We found no significant difference in pain score reductions between the two groups but some level of therapeutic benefit is not excluded. © 2010 The Authors. EMA © 2010 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.