Astigmatism decay immediately following suture removal

In a prospective study of 34 patients with high post-operative astigmatism (mean 6.90 D, range 2.75-15.00 D) following extracapsular cataract surgery (13 limbal sections and 21 corneal sections), we used keratometry to assess the changes in corneal curvature seen within 30 minutes of suture removal and compared these with the astigmatism found 2 weeks later. The greatest change occurred within the first 5 minutes of suture removal (mean 3.63 D; 95% confidence interval (95% CI) 2.85-4.41). The rate of decay then declined so that between 15 and 30 minutes the mean change was 0.56 D (95% CI 0.43-0.69). At 2 weeks a further mean decay of 1.29 D (95% CI 0.99-1.61) occurred. Of the 6 patients exhibiting a residual astigmatism greater than 3.00 D at 30 minutes, 4 continued to do so 2 weeks later. Our study suggests that keratometry 30 minutes following suture removal is only moderately different from that seen 2 weeks later. Although not stable enough to suggest that patients could be routinely refracted within 30 minutes of suture removal, in cases where early visual recovery is essential, such as in monocular patients, it may be reasonable to offer a temporary spectacle correction immediately following suture removal. Furthermore keratometry at 30 minutes after suture removal accurately predicts the necessity for further removal of sutures and indicates which patients can be discharged to the care of their own optometrist, making a further hospital visit unnecessary.