Plasminogen activator inhibitor in human tears after laser refractive surgery
Accepted 27 February 2008.
Purpose
To observe levels of plasminogen activator inhibitor (PAI) in human tears after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).
Setting
University medical center eye clinic.
Methods
Tear samples were collected from 46 eyes having PRK and 13 eyes having LASIK immediately before and after surgery and on the first (LASIK), third (PRK), and fifth (PRK) postoperative days. Analyses used enzyme-linked immunoassay, yielding 61 PRK PAI-1 determinations and 146 PRK and 35 LASIK PAI-2 determinations.
Results
All determinations of PRK PAI-1 were below the detection limit of 1 ng/mL of the original tear sample. In the PRK eyes, the mean PAI-2 concentration was 19.8 ng/mL ± 23.4 (SD) in preoperative tears, 112.7 ± 60.5 ng/mL immediately postoperatively, 12.1 ± 19.5 ng/mL after 3 days, and 15.5 ± 20.4 ng/mL after 5 days. In the LASIK eyes, the mean PAI-2 concentration was 19.0 ± 33.1 ng/mL preoperatively, 111.5 ± 69.2 ng/mL immediately postoperatively, and 15.7 ± 18.8 ng/mL after 1 day.
Conclusions
The similarity in the general time pattern of PAI-2 after PRK and LASIK suggests commonality in the enzymatic control response to corneal surgical wounding. Taken in the context of previous work, the observed levels of PAI-2 concentration in eyes with and without opacification suggest that in the postsurgical period, PAI-2 is not the controlling mechanism for the later development of corneal opacification and haze.
From the Departments of Ophthalmology (Csutak, Silver, Steiber, Hassan, Berta) and Biochemistry and Molecular Biology (Tőzsér, Bagossi), University of Debrecen, Medical and Health Science Center, Faculty of Medicine, Debrecen, Hungary; and the Applied Physics Laboratory (Silver), Johns Hopkins University, Laurel, Maryland, USA
Corresponding author: David M. Silver, PhD, Johns Hopkins University, Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, USA.
Drs. Csutak, Silver, Tőzsér, and Berta are co-inventors of a patent describing the use of urokinase-type plasminogen activator to prevent haze after laser vision correction surgery. No other author has a financial or proprietary interest in any material or method mentioned.
Supported in part by the Hungarian Scientific Research Fund, OTKA grants T38351 and F49055, and Hungarian Eötvös grant 9/2004, Hungary.
Szilvia Pető, University of Debrecen, Medical and Health Science Center, Faculty of Medicine, provided technical assistance.
ABSTRACT