Effects of three beta-blocker eye drops on the rabbit cornea: an electron microscope study

The effects on corneal tissue of three marketed beta-blocker eye drops, carteolol 1% and 2%, befunolol 0.5% and 1%, and timolol 0.25% and 0.5%, were studied by instilling these drops into the eyes of rabbits twice daily for two consecutive months. The corneal sections were examined under a scanning electron microscope and a transmission electron microscope. Carteolol eye drops caused no pathological change in the corneal epithelium, whereas befunolol and timolol eye drops caused pronounced desquamation of the corneal epithelium and pronounced disappearance of microvilli. None of the three beta-blocker eye drops caused pathological changes in the parenchyma or endothelium of the cornea.