Intraoperative biometry for intraocular lens (IOL) power calculation at silicone oil removal

Cataract development is common following retinal detachment surgery that necessitates silicone oil injection. Intraocular lens (IOL) power calculation in the presence of silicone oil is challenging for many reasons. The authors evaluated the accuracy of intraoperative biometry during cataract surgery in silicone-filled eyes.

Twelve cases of cataract in eyes filled with silicone oil after retinal detachment surgery were included. Preoperatively, keratometric readings were documented. Intraoperative axial length was measured following removal of silicone oil using a sterile probe of the Nidek Echoscan US800 unit. IOL power calculation was computed using the SRK/T formula. This was followed by phacoemulsification and foldable lens implantation. Postoperative refraction allowed evaluation of the accuracy of intraoperative biometry. The predictability of three different formulas was also compared (Holladay, SRK/T, and SRK II).

Seven men and five women with a mean age of 50.2 years were included in the study. The mean postoperative spherical equivalent using the described technique was 6.77 +/- 0.43 diopters. SRK/T and Holladay formula had the best predictability for high axial length eyes, whereas the three studied formulas showed no significant differences in predictability in eyes with normal axial length.

Intraoperative biometry proved to have good predictability for the absolute postoperative refractive error in cataract surgery for eyes at the time of silicone oil removal. This predictability was accurate independent of axial length.