JAN 18, 2019
Cataract/Anterior Segment, Retina/Vitreous
In this retrospective case series, investigators compared the accuracy of IOL calculation formulas in a cohort of previously vitrectomized eyes.
The study included refractive outcomes from 61 eyes of 57 patients after undergoing phacoemulsification through a clear corneal incision. All patients had a history of pars plana vitrectomy in the same eye.
The mean postoperative spherical equivalent was -0.16 D. The mean prediction error was highest for Ladas (0.45 D), followed by Hill RBF (0.33 D), Holladay 1 (0.30 D), Barrett (0.30 D), SRK/T (0.25 D), Holladay 2 (0.23 D), Wang-Koch adjusted Holladay 1 (-0.09 D) and Wang Koch adjusted SRK/T (0.04 D).
The formula with the highest percentage of predictions within ±0.50 D was the Holladay 2 (60.4%). Investigators found significant differences between the predicted and actual refractive outcomes with all formulas (P<0.05) except the WKA Holladay and WKA SRK/T.
The study was limited by a small sample size; a larger cohort may result in stronger data. Some refraction data might not be accurate due to limitations of vision from retina pathology. It would have been useful to subcategorize the cohort by axial length, anterior chamber depth and time from PPV to cataract surgery.
Overall, there is a propensity for hyperopic outcomes in cataract surgery after PPV in all formulas except Wang Koch adjusted Holladay 1, which had a small myopic outcome. Based on these findings, surgeons should aim for some myopia and counsel patients about expectations accordingly.