ARCUATE KERATOTOMY FOR THE CORRECTION OF SPHERICAL HYPEROPIA IN HUMANCADAVER EYES

BACKGROUND: A new experimental surgical technique to correct spherical hyperopia by steepening of the central corneal curvature was performe d on human cadaver eyes. METHODS: Ten eyes were used in the study. All were pretreated with glycerin to ensure a uniform corneal thickness b etween .55 and .65 mm on ultrasonic pachometry. A constant intraocular pressure of approximately 30 to 40 mm Hg was maintained in each eye b y the injection of saline into the vitreous cavity. This was verified by pneumotonometry. A vertical blade diamond knife was set at 100% of the thinnest of four paracentral readings. Each eye underwent preopera tive computed topography. One set of five eyes had 12 incisions made f ollowing a 5.75-millimeter diameter Mendez hexagonal marker that inclu ded unconnected T incisions at each junction (ie, ''Hex T'' pattern). The other set of five eyes had four arcuate incisions made following a 6-millimeter diameter zone marker; each incision was 60-degrees in ar c. Immediately after surgery, computed topography was repeated. RESULT S: The hexagonal keratotomy set of eyes had an average steepening of t he cornea of 0.80 D with a range of -1.05 to +4.38 D. The arcuate kera totomy set had an average steepening of +2.12 D with a range of +1.27 to +3.27 D. CONCLUSIONS: This study suggests arcuate keratotomy may be a more effective procedure in the correction of spherical hyperopia w hen compared with hexagonal keratotomy. The amount of corneal steepeni ng achieved in a cadaver eye model may not be the same as when perform ed in vivo.