K 736
Corneal haze after PRK effect of the individual collagen type IV synthesis on postoperative corneal transparencyC. R. F. Winkler von Mohrenfels, U. Reischl, C. P. Lohmann
Purpose: Nearly all patients show a subepithelial cloudiness of the cornea ("haze") after a PRK, which leads to a reduction of the quality of vision during twilight. Histological studies on human corneas after PRK showed, that mostly collagen type IV is responsible for corneal haze. As the synthesis of collagen type IV can not be influenced by pharmaceuticals, we would like to measure the individual collagen type IV mRNA new synthesis. in order to select patients who have an increased risk to develop corneal haze after PRK.
Methods: 34 patients (34 eyes) with a myopia from 1,5 dpt to 6,0 dpt underwent a PRK. Prior to surgery a biopsy of the epithelium was taken and the individual synthesis of collagen type IV a 3 mRNA was quantitatively determined with PCR and compared with haze and regression at 6 month.
Results: In all samples collagen type IV a 3 mRNA was detectable (0,11 and 6,42 (mean 1,47, SD 1,52)). There was a correlation between haze and the amount of collagen type IV a 3 mRNA (r= 0,87, a <0,01). No correlation was found between regression and the amount of collagen type IV a 3 mRNA (r= 0.31, a =0,075).
Conclusion: With this PCR test it is possible to determine the individual collagen type IV mRNA concentration in the corneal epithelial cells. As a further development of this test system it could be possible to establish a screening test, in order to detect patients with a pronounced new synthesis rate for collagen type IV as high risk patients.
Klinik und Poliklinik für Augenheilkunde der Universität Regensburg, Franz-Josef-Stauß-Allee 11, D-93053 Regensburg