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Ophthalmology

Toric Intraocular Lenses

Corneal astigmatism occurs due to the inequality of the corneal curvatures and needs to be addressed to achieve spectacle independence and optimal vision. Corneal astigmatism can be calculated by corneal topography, corneal tomography, keratometry, and intraoperative aberrometry. Toric intraocular lenses (IOLs) are considered the most predictive way of correcting corneal astigmatism in a patient undergoing cataract surgery, as they may correct astigmatism as low as 0.75 diopters. Monofocal and m

v1 · Reviewed Nov 8, 2026 by Automated Clinical Reviewer (Strict Verbatim v1)
  • Toric IOLs are unsuitable for patients with pre-existing posterior segment pathology, zonular instability, and irregular astigmatism.
  • Patients with preexisting retinal pathologies and who have undergone vitreoretinal surgical procedures may not be suitable candidates as their visual outcomes may be compromised due to the retinal pathologies.
  • Patients with uveitic pathologies, glaucoma, and patients who have undergone glaucoma surgeries may not achieve good visual outcomes by their primary pathologies.
  • Patients with unrealistic visual expectations.
  • Corneal scars and irregular astigmatism are relative contraindications for the placement of toric IOLs.
  • Poorly dilating pupils may hamper visualization for adequate alignment.
  • Corneal astigmatism can be calculated by corneal topography, corneal tomography, keratometry, and intraoperative aberrometry.
  • With advanced imaging technologies like Scheimpflug imaging, Purkinje images-based technologies, and optical coherence tomography, the measurement of the posterior corneal surface has helped us aim for better refractive outcomes in cataract surgery.
  • Trained optometrists are required to perform pre-operative workup of the patient, including measurement of uncorrected and best-corrected visual acuity, refraction, and ocular biometry, including axial length and keratometry values.
  • Preoperative estimation of anterior and posterior corneal astigmatism is essential to calculate the IOL power.
  • Intraoperative wavefront aberrometry rapidly replaces all these calculators to determine the power and axis.
  • Axis marking is essential to implant the toric IOLs in the desired axis and achieve optimal visual outcomes.
  • Placido disc-based topography with ray tracing aberrometer may provide power maps, corneal curvatures, and internal, corneal, and total higher-order aberrations.
Barrett toric calculator
The Barrett toric calculator has better predictability since it considers both estimated lens position and posterior corneal power.
Online toric calculators
Various online calculators and formulae are available for calculating the IOL power and axis of implantation.
  • Toric IOLs are considered the most predictable way of correcting corneal astigmatism.
  • Toric IOLs are ideal for candidates with preexisting corneal astigmatism greater than 1 D.
  • Patients who desire spectacle-free near vision can be counseled for multifocal toric IOLs.
  • The IOL with the least amount of residual astigmatism is chosen.
  • The IOL is implanted into the bag with the axis markings left around 3 to 5 degrees anticlockwise to the final lens position.
  • The viscoelastic is removed completely from the anterior chamber and behind the IOL in the bag, and the wound is hydrated before the final rotation of the IOL is made to align with the axis.
Toric IOLs
Intraocular
Adult
Not specified in source
Renal
Not specified in source
Duration
Not specified in source
  • The various methods of correcting corneal astigmatism during cataract surgery include toric intraocular lenses (IOL), the placement of the clear corneal phacoemulsification incision on the steeper corneal axis, paired opposite clear corneal incisions over the steeper meridian, and limbal relaxing incisions over the steeper meridians.
  • Corneal scars and irregular astigmatism are relative contraindications for the placement of toric IOLs.
  • Intraoperative posterior capsular rent is a relative contraindication as it may lead to IOL decentration or tilt in the postoperative period.
  • Realignment of the IOL has to be considered in cases with more than 10 degrees of malalignment.
  • Corneal ablative procedures, piggyback IOLs, and IOL exchange procedures are required for higher degrees of astigmatism not amenable to rotation alone.
  • The most common concern is the postoperative misalignment of the IOL, which can be prevented by washing the viscoelastic from the anterior chamber and the capsular bag to avoid postoperative rotation.
  • The patient is asked to maintain a supine position an hour after surgery to avoid changes in the IOL position.
  • The postoperative IOL alignment can be confirmed by refraction, dilated examination to look for the IOL axis, keratometry, and ray tracing aberrometer.
  • Postoperative steroids are prescribed in tapering doses.
  • IOL misalignment may occur secondary to either incorrect calculation of the IOL axis, incorrect placement of the IOL intraoperatively, or due to postoperative rotation.
  • When the misalignment exceeds 30 degrees, it may induce a cylindrical power in a new meridian.
  • One degree of misalignment leads to a 3% loss of effective power, and 30 degrees of misalignment results in the loss of the entire toric effect with significantly worse visual acuity.
  • Postoperative IOL rotation may occur as early as one hour to up to ten days post-surgery.
  • review
    Toric Intraocular Lenses. StatPearls [Internet] — Arthi Mohankumar, Sashwanthi Mohan — StatPearls Publishing, 2023

Decision support only. Verify against local protocols and current labeling. Source: www.ncbi.nlm.nih.gov