Oblique versus vertical-horizontal incision orientation in four-incision radial keratotomy.

Abstract

Four-incision radial keratotomy is used for the correction of mild to moderate myopia. The traditional orientation of incisions was naturally on the horizontal and vertical meridians. We undertook a comparative study of oblique versus traditional four-incision radial keratotomy (orthogonal orientation) to show the advantage of an oblique incision orientation. A prospective study of two groups of 21 eyes was conducted: an orthogonal group with vertical-horizontal orientation of the four incisions, and an oblique group with four obliquely oriented incisions. Spatial contrast sensitivity, glare, and night vision tests were performed and results compared. The follow up period was 3 months. Glare and contrast sensitivity were less affected with oblique orientation of incisions. There was no significant difference regarding night vision effects. We observed a decrease in induced astigmatism with oblique orientation. The location of horizontal incisions within the palpebral fissure and the unequal lengths of horizontal and vertical incisions are responsible for ocular alterations. An oblique orientation is preferable to avoid glare, starburst, and induced astigmatism.