Ab interno radial keratotomy

We describe a modified approach to perform radial keratotomy which was tested in human donor eyes. Using a Beaver blade #5910, the sclera was entered tangentially 1 mm from the limbus up to the edge of the optical zone while staying in the deep stroma. The shaft was rotated 90 degrees, allowing the cutting edge to dissect from the deep stroma to the epithelium in a radial fashion. The procedure was repeated resulting in eight radial incisions. An average of 8.20 diopters (standard deviation SD = 2.40 D) of flattening was obtained in 20 human donor eyes. Histopathologic study of the radial incisions in another group of 10 donor eyes revealed a mean depth of 58.9% of corneal thickness. (SD = 12.4%). The present technique allows radial keratotomy to be performed without the sophisticated instrumentation necessary for the "external" approach.