Ku. Sandvig et al., REGENERATION OF EPITHELIAL DEFECTS IN CORNEAS PREVIOUSLY TREATED WITHEXCIMER-LASER - A STUDY OF CELL-KINETICS IN THE RAT CORNEAL EPITHELIUM, Acta ophthalmologica Scandinavica, 76(4), 1998, pp. 442-446
Purpose: The present study was to investigate, using cell kinetic meth
ods, whether previous excimer laser treatment affected healing of late
r corneal epithelial erosions. Methods: The right eyes of rats underwe
nt central excimer corneal stromalepithelial ablations (ArF 193 mm, 22
8 pulses, diameter 3,5 mm, 17,3 mJ per pulse, depth about one third of
corneal thickness) and were allowed to heal for 15 weeks. Then centra
l circular epithelial abrasions (diameter 3 mm), using N-Heptanol and
mechanical debridement, were made on both corneas. The rats were kille
d 1,2,4 and 6 days after the last treatment. The central stromal thick
ness, the epithelial cell density, the labelling index (LI) and the mi
totic rate (MR) of the peripheral, the midperipheral and the central a
reas of the corneal epithelium were calculated for each timepoint. Res
ults: The central stromal thickness increased equally in the two group
s the first day after making the erosion, normalising in both groups d
uring the following days, The corneal epithelium was restored at the s
ame rate in both groups. The cell number per microscopic visual field,
the LI and the MR were very similar for the two groups at all timepoi
nts. Conclusion: Previous excimer laser treatment does not seem to int
erfere with healing of later epithelial erosions, when studied with ce
ll kinetic methods.