title: The effect of dorzolamide 2% on circadian intraocular pressure in cats with primary congenital glaucoma.
abstract: OBJECTIVE
  To determine the extent of fluctuation in circadian intraocular pressure (IOP) and the efficacy of topical dorzolamide 2% q 8 h in lowering IOP and blunting circadian fluctuation in IOP in glaucomatous cats.
  
  
  METHODS
  Seven adult cats with primary congenital glaucoma (PCG).
  
  
  METHODS
  Measurements of IOP and pupil diameter were obtained for both eyes (OU) of each cat q 4 h for 12 days. Cats were housed in a laboratory animal facility with a 12-h light:dark cycle. Baseline values were established for 2 days. For the next 5 days, placebo (1.4% polyvinyl alcohol) was administered OU q 8 h. Dorzolamide 2% was then administered OU q 8 h for a further 5 days. A multivariate mixed linear model was fitted to the data, with parameters estimated from a Bayesian perspective. The 4 am time point was selected as the reference for the purposes of comparisons.
  
  
  RESULTS
  Estimated mean IOP for the reference time point pre-treatment was symmetric (about 33 mmHg OU). In all cats, IOP was significantly lower during the diurnal phase, relative to the 4 am measurements, with highest IOP observed 2-6 h after the onset of the dark phase. Circadian fluctuations in IOP were dampened during the treatment period. There was a significant decrease in IOP in all cats during the dorzolamide treatment period (estimated mean for the treatment period reference = 17.9 mmHg OU).
  
  
  CONCLUSIONS
  Topical dorzolamide 2% q 8 h is effective in reducing IOP and IOP fluctuation in cats with PCG.
authors.affiliation: Department of Veterinary Clinical Sciences, Iowa State University, Ames, IA 50011, USA.
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Sigle
authors.forename: Gabriel
authors.initials: G
authors.lastname: Camaño-Garcia
authors.forename: Alicia L
authors.initials: AL
authors.lastname: Carriquiry
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Betts
authors.forename: Markus H
authors.initials: MH
authors.lastname: Kuehn
authors.forename: Gillian J
authors.initials: GJ
authors.lastname: McLellan
mesh_terms: D060433:Administration, Ophthalmic / Q000662:veterinary; D000818:Animals; D002257:Carbonic Anhydrase Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D002371:Cat Diseases / Q000151:congenital / Q000188:drug therapy* / Q000503:physiopathology; D002415:Cats; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D005901:Glaucoma / Q000151:congenital / Q000188:drug therapy / Q000503:physiopathology / Q000662:veterinary*; D007429:Intraocular Pressure / Q000187:drug effects* / Q000502:physiology; D008297:Male; D013449:Sulfonamides / Q000008:administration & dosage / Q000627:therapeutic use*; D013876:Thiophenes / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D002257:Carbonic Anhydrase Inhibitors; D013449:Sulfonamides; D013876:Thiophenes; C062765:dorzolamide