Abstract
Purpose:
To investigate the corneal toxicity of three combined antiglaucoma topical eye drops using transepithelial electrical resistance (TER) and scanning electron microscopy (SEM).
Methods:
Corneal TER changes after a 60 second exposure to Xalacom (latanoprost 0.005%/ timolol maleate 0.5% preserved with 0.02% BAC), Duotrav (travoprost 0.004% / timolol maleate 0.5% preserved with polyquaternium-1 0.001%), and Cosopt (dorzolamide1%/ timolol maleate 0.5% preserved with 0.005% BAC) were measured in living rabbits. Corneal damage was also examined by SEM. Hank’s Balanced Salt Solution (HBSS) was used as a control.
Results:
There was a significant decrease in the corneal TER after exposure of the cornea to Xalacom (P <0.01). Duotrav and Cosopt did not produce any significant decrease in the corneal TER as compared to HBSS control eyes. Superficial cells were damaged and exhibited degenerated microvilli with Xalacom solution revealed with SEM. Conversely, the superficial cells of the cornea exposed to Duotrav and Cosopt appeared normal in appearance with normal microvilli under SEM examinations.
Conclusions:
The corneal toxicity of Xalacom is more than that of Duotrav and Cosopt. Xalacom contains 0.02% BAC which may be the responsible for that corneal toxicity.