Corneal astigmatism induced by superior versus temporal corneal incisions for extracapsular cataract extraction.
OBJECTIVE
We tested the hypothesis that superior corneal sections induce a shift to 'against-the-rule' astigmatism and temporal corneal sections lead to the preferred 'with-the-rule' astigmatism.


METHODS
We conducted a prospective randomised trial of superior versus temporal corneal incisions in extracapsular cataract surgery in a hospital practice. Thirty nine eyes of 37 patients were included. The induced astigmatism was analysed by three methods.


RESULTS
When analysed by Cravy's method of induced astigmatic cylinders, the superior incision induced a greater degree of 'with-the-rule' astigmatic cylinder prior to sutures removal on day 77 (P < 0.049). Long term, the temporal incision produced 1.44 dioptre of 'with-the-rule' astigmatism, while the superior section produced 0.08 dioptre of 'against-the-rule' astigmatism (P < 0.001).


CONCLUSIONS
The results of this small trial indicates that the superior corneal incision produces significantly less astigmatism than the temporal incision. The temporal incision induces a moderate degree of 'with-the-rule' astigmatism.
Wong
H C
HC
Department of Ophthalmology, Flinders Medical Centre, South Australia.
Davis
G
G
Della
N
N
D000368:Aged; D001251:Astigmatism / Q000209:etiology* / Q000503:physiopathology; D002387:Cataract Extraction / Q000009:adverse effects / Q000379:methods*; D003315:Cornea / Q000502:physiology / Q000601:surgery*; D005260:Female; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D011446:Prospective Studies