[Astigmatism caused by superior and temporal corneal incisions in cataract surgery].
OBJECTIVE
To compare induced astigmatism and postoperative astigmatism of a 4 mm corneal superior incision to a 4 mm temporal incision for cataract phacoemulsification surgery.


METHODS
Sixty eyes underwent cataract surgery for this prospective study. Thirty had a superior corneal incision (group 1) and 30 had a temporal incision (group 2). The incision was placed according to the pre operative astigmatism:temporal approach in case of against the rule astigmatism and superior location in case of with the rule astigmatism. The incision was enlarged to 4 mm just before implantation of a foldable lens. The patients had a pre operative and a post operative (day 1, 8, 30, 180) keratometry. Some had a corneal topography too. The surgically induced astigmatism was calculated using Naeser method.


RESULTS
The incision having a relaxing effect on the meridian where it is placed, the surgically induced astigmatism is against the rule for a superior location and with the rule for a temporal location. At day 30 the mean surgically induced astigmatism was 0.98 diopter in group 1 and 0.58 in group 2. At ay 30 the postoperative astigmatism was 0.51 diopter against the rule in the first group and 0.13 diopter with the rule in the second group.


CONCLUSIONS
The superior corneal incision rarely allows to reach a minimum postoperative astigmatism as with a temporal location.
Roman
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Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris.
Ullern
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M
D000368:Aged; D001251:Astigmatism / Q000209:etiology*; D002387:Cataract Extraction / Q000009:adverse effects*; D003315:Cornea / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D013997:Time Factors; D014792:Visual Acuity