[Corneal topography after cataract surgery with tunnel incision on a steeper meridian in inverse and oblique astigmatism].
Scleral tunnel incision at the 12 o'clock-position for no-stitch cataract surgery can increase preexisting against-the-rule astigmatism by flattening the vertical corneal meridian. An oblique axis can change by operative induction. We investigated, in a prospective study, whether reduction of such a preoperative astigmatism could be induced by locating the tunnel incision on the steeper meridian. Eighteen eyes with senile cataract and against-the-rule or oblique astigmatism of at least 0.7 diopters were operated with a standardized 5 x 6 mm scleral tunnel incision and a 6 mm PMMA posterior chamber lens. We evaluated the astigmatism with a videokeratoscopy TMS-I preoperatively and about 6 months after the surgery. The mean corneal astigmatism was 1.8 diopters pre- and 1.5 diopters postoperatively. A reduction of keratometric astigmatism was reached in 72% of cases; 17% remained unchanged. The surgically induced astigmatism calculated by Jaffer's and Clayman's vector analysis was 0.68 diopters. The technique of scleral tunnel incision with lateral or oblique approach can reduce a preexisting against-the-rule or oblique astigmatism.
Heider
W
W
Universitäts-Augenklinik, Frankfurt/Main.
Müller
M
M
Schalnus
R
R
Kaiser
P
P
D001251:Astigmatism / Q000209:etiology / Q000601:surgery*; D002387:Cataract Extraction / Q000379:methods*; D005500:Follow-Up Studies; D006801:Humans; D007910:Lenses, Intraocular; D011183:Postoperative Complications / Q000209:etiology; D011446:Prospective Studies; D012590:Sclera / Q000601:surgery