JUN 04, 2013
This literature review found that toric and multifocal toric IOL implantation results in excellent distance and near visual acuity and spectacle independence in patients with cataract and corneal astigmatism.
The authors reviewed literature relevant to currently available toric and multifocal toric IOLs, including relevant patient selection criteria, IOL calculation issues, surgical techniques and clinical outcomes.
They found that toric IOLs result in UDVA of 20/40 or better in almost all patients. Depending on the toric IOL model, UDVA of 20/25 or better was reported in 20 percent to 80 percent of patients. Spectacle independence for distance vision following bilateral toric IOL implantation ranged from 70 percent to 100 percent of eyes.
With multifocal toric IOLs, they say it has been demonstrated that an optimal astigmatism correction is necessary to achieve optimal distance and near visual acuities. Corneal astigmatism of 1.0 D or possibly less should be corrected when implanting a multifocal IOL. Clinical studies evaluating multifocal toric IOLs showed good visual outcomes for distance and near, but only moderate visual outcomes for intermediate distances.
They also found that misalignment is uncommon due to accurate alignment during surgery and the rotational stability of these IOLs.
They say it appears that a minimal amount of corneal astigmatism of approximately 1.25 D should be present before toric IOL implantation is considered. Patients with regular bowtie astigmatism are most suitable for toric IOL implantation, and irregular astigmatism is a relative contraindication. To detect irregular astigmatism, corneal topography using Placido-disk videokeratoscopy or Scheimpflug imaging should be performed preoperatively.