title: Timolol and pilocarpine are hypotensive in light-induced avian glaucoma.
abstract: Two antiglaucoma drugs were tested on Hubbard chicks with light-induced avian glaucoma (LIAG). This animal model for open-angle glaucoma was further assessed by a novel method for monitoring aqueous inflow and outflow simultaneously. When the chicks were 8 to 9 weeks of age the preglaucomatous eyes were significantly enlarged (p less than 0.001), weighing a mean of 3.37 g, compared with 2.59 g for a group of normal eyes, but the intraocular pressure (IOP) was slightly lower in the former (13.79 v. 16.46 mm Hg; p less than 0.05). At this age the aqueous outflow was markedly reduced (to 0.70 v. 2.47 microL/min; p less than 0.05), but no change in aqueous inflow could be demonstrated. By 18 to 20 weeks the glaucomatous eyes were further enlarged (mean weight 4.67 v. 3.76 g; p less than 0.001) and hypertensive (mean IOP 29.85 v. 22.27 mm Hg; p less than 0.05). Timolol elicited a 29% to 33% reduction in the IOP at 8 to 9 weeks in both groups of eyes. At 18 to 20 weeks it reduced the IOP of the glaucomatous eyes to normal values but caused a less marked reduction in the normal eyes. Pilocarpine elicited an initial sharp rise in the IOP but was ultimately hypotensive, causing about a 33% decrease from the preinfusion IOP, in both young and adult birds.
mesh_terms: D000818:Animals; D001082:Aqueous Humor / Q000502:physiology; D002645:Chickens; D005123:Eye / Q000473:pathology; D005901:Glaucoma / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D007275:Injections, Intravenous; D007429:Intraocular Pressure / Q000187:drug effects*; D008027:Light / Q000009:adverse effects*; D010862:Pilocarpine / Q000008:administration & dosage / Q000627:therapeutic use*; D011833:Radiation Injuries, Experimental / Q000188:drug therapy; D013999:Timolol / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D010862:Pilocarpine; D013999:Timolol