Corneal pharmacodynamics after photorefractive keratectomy and laser in situ keratomileusis in rabbits.
OBJECTIVE
To evaluate changes in corneal pharmacodynamics after PRK and LASIK in rabbits.


METHODS
Two groups of five rabbits (10 eyes) each received PRK and LASIK, and an unoperated third group was used as a control. Dexamethasone, efflumidex, diclofenac, and tobramycin were applied. Anterior chamber aqueous was collected every 20 minutes and analyzed by spectrophotometry. Histological studies were performed to find drug deposits in the cornea.


RESULTS
The coefficient of diffusion after PRK was determined for dexamethasone (3.2 x 10(-4) cm/min), efflumidex (1.4 x 10(-4)), diclofenac (7.4 x 10(-5)), and tobramycin (5.4 x 10(-6)). After LASIK, the coefficient of diffusion for dexamethasone was 3.4 x 10(-5); efflumidex, 1.7 x 10(-5); diclofenac, 8.8 x 10(-6); and tobramycin, 2.4 x 10(-6) cm/min. Total time of passing through the cornea after PRK and LASIK was also measured: dexamethasone 45 and 70 min, efflumidex 50 and 115 min, diclofenac 60 and 200 min, and tobramycin 335 and 690 min. Histologically a drug deposit area was found in corneas after LASIK under the flap. In the control group, coefficient of diffusion for dexamethasone was 1.2 x 10(-5) cm/min, efflumidex 1.5 x 10(-5), diclofenac 6.4 x 10(-6), and tobramycin 2.1 x 10(-6). Total time of passing through the cornea for the control group for dexamethasone was 60 min, efflumidex 105 min, diclofenac 160 min, and tobramycin 540 min.


CONCLUSIONS
Coefficient of diffusion increased after photorefractive surgery.
Maitchouk
Dmitri
D
New Line Vision, Moscow, Russia. nlvision@online.ru
Smirennaia
Elena
E
Kourenkov
Vyacheslav
V
D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000494:pharmacology; D000893:Anti-Inflammatory Agents / Q000493:pharmacokinetics / Q000494:pharmacology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000493:pharmacokinetics / Q000494:pharmacology; D001082:Aqueous Humor / Q000378:metabolism; D003315:Cornea / Q000187:drug effects / Q000378:metabolism* / Q000601:surgery*; D003907:Dexamethasone / Q000493:pharmacokinetics* / Q000494:pharmacology; D004008:Diclofenac / Q000493:pharmacokinetics* / Q000494:pharmacology; D015590:Fluorophotometry; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer; D009883:Ophthalmic Solutions / Q000493:pharmacokinetics / Q000494:pharmacology; D018903:Photorefractive Keratectomy; D011817:Rabbits; D014031:Tobramycin / Q000493:pharmacokinetics* / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D000893:Anti-Inflammatory Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D009883:Ophthalmic Solutions; D004008:Diclofenac; D003907:Dexamethasone; D014031:Tobramycin