title: Change in corneal permeability to timolol after laser in situ keratomileusis and photorefractive keratectomy in rabbit.
abstract: OBJECTIVE
  To evaluate the change in corneal permeability to timolol 1 month after laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) in rabbits.
  
  
  METHODS
  LASIK or PRK was performed on one eye of each of 20 rabbits. One month later, 20 microl of 0.5% timolol was instilled into the 10 LASIK eyes, 10 PRK eyes, and the 20 control contralateral eyes. One hour later, 150 microl of aqueous humor was collected from all eyes, and the concentration of timolol in the aqueous humor was measured by high-performance liquid chromatography. The effect of LASIK and PRK on the corneal permeability to timolol was analyzed.
  
  
  RESULTS
  The average timolol concentrations in the aqueous humor of the ten eyes 1 month after LASIK and in the ten contralateral eyes were 1.16 +/- 0.58 microg/ml and 1.07 +/- 0.39 microg/ml (average +/- SD, P = 0.678), respectively. The average timolol concentrations in the aqueous humor of the ten eyes 1 month after PRK and in the ten contralateral eyes were 1.24 +/- 0.43 microg/ml and 1.12 +/- 0.30 microg/ml (P = 0.483), respectively. The average ratio of timolol concentration in the aqueous humor of the LASIK or PRK eyes 1 month after surgery to that of the contralateral normal eyes was 1.18 +/- 0.58 or 1.19 +/- 0.67 (P = 0.972), respectively.
  
  
  CONCLUSIONS
  LASIK and PRK do not affect corneal permeability to timolol 1 month after surgery.
authors.affiliation: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo 113-8655, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Hamada
authors.forename: Shiro
authors.initials: S
authors.lastname: Amano
authors.forename: Satoru
authors.initials: S
authors.lastname: Yamagami
authors.forename: Makoto
authors.initials: M
authors.lastname: Araie
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Oshika
authors.forename: Takahiro
authors.initials: T
authors.lastname: Wada
authors.forename: Hiroko
authors.initials: H
authors.lastname: Miyai
authors.forename: Yoshitada
authors.initials: Y
authors.lastname: Notsu
mesh_terms: D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D003315:Cornea / Q000378:metabolism* / Q000601:surgery*; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer; D010539:Permeability; D018903:Photorefractive Keratectomy; D011817:Rabbits; D013999:Timolol / Q000493:pharmacokinetics*
chemical_list: D013999:Timolol