Accuracy of Intraocular Lens Power Calculation in Eyes Filled with Silicone Oil.

Silicone oil (SO) is used mainly when managing complex retinal detachments, commonly with proliferative vitreoretinopathy, as well as a hemostatic agent in proliferative diabetic retinopathy. Combined lens exchange and pars plana vitrectomy remains preferred by many surgeons; however, sequential surgery might be advantageous to minimize the postoperative anterior chamber inflammatory response, particularly in proliferative diabetic retinopathy or retinal detachment. The aim of the study was to evaluate the optimal method of intraocular lens (IOL) calculation in eyes filled with SO. Different techniques are employed for axial length assessment in eyes filled with SO, including preoperative A-scan applanation or immersion biometry, partial coherence interferometry (PCI), or less commonly computed tomography, magnetic resonance imaging, or intraoperative retinoscopy/biometry after SO removal. PCI might provide better refractive outcomes compared to ultrasound measurements, however, the quality of presented evidence is low. Bias in calculation may be a result of limited vitreous base removal during vitrectomy, partial filling of the vitreous chamber with SO and measurements in supine position, macular edema or detachment, selection of an inappropriate IOL calculation formulas and sulcus IOL placement. Clinicians should consider that even when employing optical biometry and correct calculation formulas only a third of eyes filled with silicone oil might achieve ± 1.0 D of target refraction, compared to 97.2% of normal eyes. We would recommend performing optical biometry before the application of SO; if this is impossible, measurement of the second eye or biometry after SO removal is an alternative. Implantation of a convex-plano monofocal polymethyl methacrylate or foldable hydrophobic acrylic IOL with large optic diameter is advised in these patients.