2020–2021 BCSC Basic and Clinical Science Course™
13 Refractive Surgery
Chapter 8: Intraocular Refractive Surgery
Toric Intraocular Lenses
Residual astigmatism after cataract surgery impacts visual function and patient satisfaction. Large population analyses indicate that more than 50% of patients have 0.75 D or more corneal astigmatism at presentation for cataract surgery, and 15%–29% have 1.50 D or more corneal astigmatism. Thus, toric IOLs can address a major need for vision correction after crystalline lens removal. Current toric IOLs in the United States generally come in powers that can correct from 1.00 to 4.00 D of astigmatism at the spectacle plane, and wider power ranges are available outside the United States; however, this range is continually evolving.
A toric IOL is appropriate for patients with regular corneal astigmatism, currently up to 4.00 D at the corneal plane (United States). Patients with astigmatism exceeding the upper correction limits require additional measures to obtain full correction. In addition to understanding the risks associated with intraocular surgery, patients must be capable of understanding the limitations of a toric IOL. Not all patients with toric IOL implantation achieve spectacle independence for distance vision. Further, patients should be informed that toric IOL implantation will not eliminate the need for reading glasses (unless monovision is planned). The patient also needs to be informed that the IOL may rotate in the capsular bag shortly after surgery and that an additional procedure may be required to reposition it. A silicone toric IOL may be less appropriate for patients who may carry a significant potential of requiring silicone oil for retinal detachment repair in the future; thus, nonsilicone IOLs are more appropriate choices for these patients.
Excerpted from BCSC 2020-2021 series: Section 13 - Refractive Surgery. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.