STARK stands for Selective Treatment of Astigmatism in Radial Keratotomy. STARK is a new radial keratotomy treatment, developed at the ELZA Institute, that lifts the very flat center of the cornea towards more normal levels.
The idea behind Radial Keratotomy (RK) was simple. Myopic (short-sighted) corneas are too steep for normal vision, but by making several incisions in the cornea radiating outward, the cornea flattens, removing the myopia. The problem with RK was that many of these corneas did not stop flattening once vision was corrected – they kept on flattening. This meant that patients became hyperopic (long-sighted) like in this case example: the cornea was only 26 D steep, which is a catastrophe for visual quality and leaves the patient at +10 D of hyperopia.
Three months after the STARK procedure, the center of the cornea is far more homogeneous and, more importantly, is up to 5 D steeper than before. Best corrected vision doubled from 20% with glasses to 40% with glasses. Moreover, it will be easier to fit good contact lenses to achieve even better vision.
Figure 1: STARK: Before (A), after (B) and the difference map (C).