[Prospective study of contrast sensitivity and visual effects after LASIK].
OBJECTIVE
To evaluate changes in visual effects (contrast sensitivity, halos, and glare) following laser in situ keratomilleusis (LASIK).


METHODS
In this prospective study, 72 eyes had LASIK to correct myopia. Contrast sensitivity was tested preoperatively, as well as 6 and 12 months postoperatively. The spatial frequencies tested were 3, 6, 12, and 18 cycles per degree (c/d). There were two groups: group 1 for myopia between -6 D (n=30) and -7.5 D and group 2 for myopia between -7.5 D and -10 D (n=25). There were 17 cases with loss of sight. For each visit, pupil diameter, halos, and glare were measured.


RESULTS
Contrast sensitivity was better in group 1 than in group 2 (p<0.05) (for spatial frequencies of 3, 12, 18, c/d). In group 1, contrast sensitivity decreased 6 months postoperatively for all spatial frequencies (p<0.05); 12 months after surgery the changes were not significant. In group 2, changes were not significant. For halos and glare, pre- and postoperative percentages were not different. There was no correlation with pupil diameter.


CONCLUSIONS
After LASIK to correct myopia, there may be a persistent decrease in contrast sensitivity. Changes are only significant at 6 months postoperatively. Patients should be informed preoperatively of this possible decrease in functional vision.
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Service d'Ophtalmologie, Pavillon C, Hôpital Edouard Herriot, 5, place d'Arsonval, 69003 Lyon. david.donate@wanadoo.fr
Denis
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Burillon
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D000328:Adult; D015350:Contrast Sensitivity; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D008297:Male; D009216:Myopia / Q000601:surgery*; D011446:Prospective Studies