gms | German Medical Science

Striae are a rare but dreaded complication after laser in situ keratomileusis, which may affect the quality of vision. Risk factors for the formation of striae are high myopia, a thin flap and dehydration of the flap during ablation. Some cases require further surgery, which often includes abrasion of the epithelium on the flap center.

A 62-year-old patient scheduled for enucleation due to choroidal melanoma unterwent LASIK with a high ablation (-12 D spherical equivalent), a thin flap (110 micron) and manipulation of the flap during surgery. Sixteen hours after LASIK the eye was enucleated and histology of the cornea was obtained.

Striae are visible as V-shaped indentations of Bowman's membrane and the anterior stroma. The epithelium shows 2 to 5 layers of cells, depending on the prominence of the striae. Hyperplasia of epithelial cells adjacent to the basement membrane is seen in "valleys" between striae. Nuclei present few mitotic divisions.

Even 16 hours after LASIK the epithelium tends to smoothen the corneal surface by filling out "valleys" between striae. The epithelium, which is the main cause for the recalcitrance of flap striae, adapts to the corneal irregularities by hyperplasia and proliferation of epithelial cells.