Stability of Astigmatism Following Lensectomy for Pediatric Cataract

To evaluate change in astigmatism after postoperative healing was completed through 5 years following pediatric lensectomy with primary IOL implantation DESIGN: Post hoc analysis of a prospective cohort study PARTICIPANTS: Children <13 years of age who had early postoperative (60 days to 1.5 years postoperatively) and 5-year refraction data (4-6 years postoperatively).

Change in astigmatism.

Change in astigmatism was calculated in 2 ways: (1) using clinical notation for astigmatism without regard to axis change and (2) using cylinder conversion to power vectors (J0, J45) to include the impact of axis changes. With conversion back to clinical notation, we calculated the change in the astigmatic component of the refraction between the early postoperative exam and 5 years.

Among 213 children, mean (SD) age was 5.4 (3.2) years; among 266 study eyes, 153 (58%) were from bilateral cases. Mean clinical astigmatism was + 1.24 D (95% confidence interval [CI] 1.11-1.38 D) at early postoperative exams and + 1.61 D (95% CI: 1.47-1.75 D) at 5 years (mean change: +0.37 D, 95% CI: 0.26 to 0.48 D). Using power vector conversions, the mean change in astigmatism was 1.06 D (95% CI: 0.95-1.18 D). The proportions of children with astigmatism > 0.50 D postoperatively (N = 185) who had a change ≥ 1.00 D and ≥ 2.00 D were 47% (95% CI: 40%-55%) and 16% (95% CI: 11%-22%), respectively. Change in astigmatism was not associated with age at lensectomy (0.00 D per 1 year older, 95% CI: -0.04 to 0.04, p = .92) when analyzed with power vector conversions.

When disregarding axis change, there was less than 0.50D increase in clinically determined astigmatism 5 years after cataract surgery. However, analysis of astigmatism change using power vectors with conversion back to clinical notation (accounting for change in magnitude and axis), about 1 in 6 eyes had a change of 2.00 D or more in the astigmatic component of their refraction. This suggests that toric IOLs may not be appropriate for pediatric cataract surgery.