More than half of patients undergoing modern cataract or lens replacement surgery have clinically significant corneal astigmatism.¹ Ignoring it does not produce neutral vision, it produces blurred vision. Toric IOLs are the most precise tool for correcting astigmatism at the lens plane.
How They Work
A toric IOL has cylindrical power built into its optic. The cylindrical correction is positioned along a planned axis that aligns with the patient’s corneal astigmatism, neutralising the optical error at the level of the lens.² Trifocal and EDOF platforms are available in toric versions, allowing astigmatism correction without compromising range-of-vision benefits.
Why Precision Matters
Toric alignment is unforgiving. A 10° rotation reduces astigmatic correction by approximately one third, and a 30° rotation eliminates it entirely.³ Surgical marking, intraoperative imaging guidance, and digital positioning systems are designed to minimise misalignment. Postoperative rotation, while uncommon, can require reoperation for repositioning.
Pre-Operative Essentials
Accurate astigmatism correction depends on precise corneal measurements obtained from multiple modalities, including keratometry, topography, and tomography. Posterior corneal astigmatism, often missed by anterior-only keratometry, is now incorporated into modern toric calculations and influences final outcomes.
The Clinical Position
Toric lenses are not a luxury upgrade. For patients with more than approximately 0.75 D of corneal astigmatism, a non-toric lens leaves vision blurred in a way that no laser enhancement can fully address without further intervention. Astigmatism management is built into the planning, not added afterwards.
References
- Hoffmann PC, Hütz WW. Analysis of biometry and prevalence data for corneal astigmatism in 23,239 eyes. J Cataract Refract Surg. 2010;36(9):1479-1485.
- Visser N, Bauer NJ, Nuijts RM. Toric intraocular lenses: historical overview, patient selection, IOL calculation, surgical techniques, clinical outcomes, and complications. J Cataract Refract Surg. 2013;39(4):624-637.
- Kessel L, Andresen J, Tendal B, Erngaard D, Flesner P, Hjortdal J. Toric intraocular lenses in the correction of astigmatism during cataract surgery: A systematic review and meta-analysis. Ophthalmology. 2016;123(2):275-286.
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