Ultrastructural effects of topical betoptic, betagan, and timoptic on the rabbit corneal endothelium.
Scanning and transmission electron microscopy was used to evaluate the cytotoxic effect of three commercially available beta adrenergic blockers (Betoptic 0.5%, Betagan 0.5% and Timoptic 0.5%), and preservative (benzalkonium chloride 0.01%) on rabbit corneal endothelium. Evaluation was performed on groups including intact corneas, de-epithelialized corneas, full-thickness corneal grafts with intact epithelium, and de-epithelialized corneal grafts. Both Betoptic and Betagan produced minor damage to endothelial microvilli in the intact epithelial group. The de-epithelialized and the grafted-cornea groups had less damage induced by Betoptic than Betagan. Timoptic produced more endothelial damage than Betoptic and Betagan in all groups. Benzalkonium chloride produced minimal endothelial damage. Results indicate that Betoptic produces less endothelial toxicity than the two non-specific beta blockers when corneal epithelium is damaged and after penetrating keratoplasty.
Liu
G S
GS
Department of Ophthalmology, University of Toronto, Ontario, Canada.
Trope
G E
GE
Basu
P K
PK
D000287:Administration, Topical; D000818:Animals; D015784:Betaxolol / Q000008:administration & dosage / Q000633:toxicity*; D004728:Endothelium, Corneal / Q000187:drug effects / Q000648:ultrastructure*; D004848:Epithelium / Q000502:physiology; D015948:Keratoplasty, Penetrating / Q000473:pathology; D011817:Rabbits; D013999:Timolol / Q000008:administration & dosage / Q000633:toxicity
D013999:Timolol; D015784:Betaxolol