Abstract
Purpose :
Various clinical conditions may cause dilation of the conjunctival vessels, leading to ocular redness (OR), among which allergic conjunctivitis is the most common cause, followed by dry eye disease and infectious conjunctivitis. Herein, using animal models of both allergic and non-allergic OR, we evaluated the therapeutic efficacy of topical blockade of substance P (SP) in treating the red eye.
Methods :
Allergic OR was induced in Guinea pigs with topical 1.5 mg/mL histamine, and non-allergic OR was induced in rabbits with topical 5% dapiprazole. Once topical histamine or dapiprazole was applied, animals immediately received topical treatment of L-703,606, a SP receptor antagonist, or vehicle. Animal eyes were thereafter examined by a slit lamp, and images were taken every 30 seconds in the first 2 minutes, and then at 6, 10, 20, 30, 40, 50, and 60 minutes post treatment. The severity of redness was analyzed using ocular redness index (ORI) which is a continuous numerical score from 0 to 100.
Results :
In the vehicle control group, the ORI reached peak at 10 minutes in allergic OR and the maximal increase from baseline was 17.04. In the non-allergic OR model, maximal increase in ORI score is 13.07 at peak time of 20 minutes post-induction. Topical treatment of L-703,606 significantly reduced ORI at each time point evaluated in both allergic and non-allergic OR models. At peak time, L-703,606 treated group showed ORI reduction of 8.21 in allergic model and 5.76 in non-allergic model, respectively.
Conclusions :
Topical blockade of SP is effective for treating allergic and non-allergic red eye.
This is a 2021 ARVO Annual Meeting abstract.