Predictability of intraocular lens power calculation in pediatric cataract

Purpose : To evaluate the predictability of intraocular lens (IOL) power ca lculation taking in account the changing refraction in children operated on for congenital cataract with primary posterior chamber IOL implantation. Methods: We compared the predicted (PR) and objective (OR) refraction in 89 eyes of 70 children (1 month to 16 years) (1989 to 1995) at 1 month and 3 years after cataract surgery. The eyes were divided in 4 groups. Group A: < 1 year; Group B: 1 year to 3 years; Group C: 3 years to 5 years; Group D: > 5 years. For patients operated on before 3 years of age, we used a modifi ed SRK II formula with the aim of achieving an undercorrection (85% of SRK II value in group A, 95% of SRK II value in group B). Results : The average objective refraction (OR) and the average error (AE = (OR)-(PR)) were respectively at 1 month and 3 years after surgery for the Group A: (OR: + 3.5D/- 1.8D) (AE: -1D/- 6.4D); Group B: (OR: + 1.3D/- 1.3D) (AE: - 0.9D/- 3.6D); Group C: (OR: - 0.2D/ -1.4D)(AE: + 0.ID/-1.1D); Group D (OR: + 0.ID/-1D) (AE: + 0.8D/- O.4D). Conclusion : At 1 month after surgery, the predictability of IOL power calc ulation appears accurate with a refractive error between - 1 D and + 0.8 D in the four groups. However we noted an increase in refractive error at 3 y ears with a progressive myopic shift, specially in the eyes operated on bef ore 1 year of life which had the greatest change in axial lenght.