[Biomorphometry of corneal epithelium with slit lamp-adapted optical coherence tomography]

The purpose of this study was to evaluate the biomorphometry of the corneal epithelium with slitlamp-adapted optical coherence tomography (OCT).

In a clinical study, slitlamp-adapted OCT of the cornea was performed in 15 patients before and immediately after therapeutic corneal abrasion. Central corneal epithelium thickness measurements were compared to the pre- and postoperative central corneal thickness.

Preoperatively, the corneal epithelium could be visualised from the highest OCT light reflections at the interfaces air-tear film and epithelium-Bowman's membrane. The preoperative mean geometrical central epithelial thickness determined with OCT ranged from 65 +/- 12 microns to 72 +/- 14 microns (45-92 microns). The mean difference of the pre- and postoperative central corneal thickness was 48 +/- 19 microns (9-79 microns). This resulted in a deviation from the direct epithelial thickness measurements of 26-33%. The reproducibility of the geometrical epithelial thickness was +/- 9 microns.

Slitlamp-adapted OCT enabled a noncontact evaluation of the corneal epithelium. The difference between direct and indirect corneal epithelium thickness measurements could be related to the partial optical inclusion of the precorneal tear film and the Bowman's membrane. With some restrictions the biomorphometry of the corneal epithelium with slitlamp-adapted OCT seems to be a valuable technique to monitor therapeutical and refractive procedures of the cornea.