In this episode of Interventional Mindset, Neda Shamie, MD, a cornea, cataract, and refractive surgeon at the Maloney-Shamie Vision Institute in Los Angeles, outlines contemporary strategies for astigmatism correction in cataract and refractive surgery.
She emphasized the importance of pre-operative diagnostics, intraoperative precision, and post-operative management to achieve optimal visual outcomes.
Astigmatism correction fast facts
- Astigmatism correction is essential in 2026, as patient expectations continue to rise alongside advances in available technology.
- Ocular surface optimization (e.g., dry eye, Salzmann nodules, epithelial basement membrane dystrophy, pterygium) must precede astigmatism measurements.
- Topography and tomography are critical for quantifying total corneal astigmatism and identifying irregular patterns.
- Limbal relaxing incisions (LRIs) are typically used for <0.75D; toric intraocular lenses (IOLs) are indicated above that threshold.
- Image-guided systems and intraoperative aberrometry improve toric alignment and refractive accuracy.
- Residual astigmatism can be addressed post-operatively with lens rotation, laser enhancement, or LRIs.
Deeper dive: Building an intraoperative astigmatism correction workflow
“In 2026, patients’ demands and expectations are high and the technology can match those high demands. It would be a lost opportunity not to correct astigmatism,” explained Dr. Shamie. As such, astigmatism management requires a structured, technology-driven approach spanning pre-operative planning, intraoperative execution, and post-operative refinement.
Pre-operative: Start with the ocular surface
Ocular surface disease must be addressed before measurement. Dry eye—both evaporative and aqueous-deficient—as well as corneal irregularities such as epithelial basement membrane dystrophy (EBMD), Salzmann nodules, and pterygia can distort corneal readings and lead to inaccurate IOL selection.1
Dr. Shamie emphasized that she treats these conditions first and typically waits 4 to 6 weeks before repeating diagnostics to establish a reliable baseline. Once the surface is stable, topography and tomography provide a complete assessment of corneal astigmatism.
Measuring what matters: Total corneal astigmatism
“First and foremost with astigmatism management, it's key to get good measurements ahead of time,” she noted. Manifest refraction alone is insufficient for surgical planning. Instead, total corneal astigmatism—including both anterior and posterior curvature—guides decision-making.
Topography and tomography serve two functions:
- Quantifying the magnitude of astigmatism
- Determining whether the astigmatism is regular or irregular
This distinction is critical, as irregular astigmatism (e.g., forme fruste keratoconus) is less predictable and may not be effectively corrected with toric IOLs.
Toric IOLs vs. LRIs: Choosing the right approach
Once corneal measurements are confirmed, the next step is selecting the appropriate correction strategy.
Dr. Shamie’s general approach includes:
- <0.75D astigmatism → LRIs
- ≥0.75D astigmatism → Toric IOLs
Choosing between LRIs and toric IOLs depends not only on the magnitude of astigmatism but also on patient expectations, lens choice, and overall refractive goals.
For patients seeking presbyopia correction, most multifocal IOL platforms now offer toric options, addressing up to 4D of astigmatism—an important consideration for those pursuing spectacle independence.
Intraoperative: A 3-modality alignment approach
Even with accurate planning, intraoperative alignment is essential. Cyclotorsion—the rotational shift that occurs when a patient moves from the upright to the supine position—can lead to toric misalignment.2
To improve accuracy, Dr. Shamie utilizes three modalities intraoperatively to help guide toric placement, whether it's multifocal or a monofocal toric lens:
- Image-guided femtosecond laser placement of toric alignment marks
- Intraoperative aberrometry (e.g., ORA)
- Digital alignment platforms (e.g., Callisto, Verion)
The Ally femtosecond laser (Lensar, Inc.) serves as the foundation of her approach. Using pre-operative upright imaging, the system creates capsular reference nubs that mark the intended alignment axis. These markers remain visible intraoperatively and post-operatively, providing a consistent reference point.
She supplements this with intraoperative aberrometry using the ORA system—particularly for higher corrections—and digital tracking with Callisto (ZEISS). Together, these tools support consistent on-axis toric placement.
Post-operative care: Managing residual astigmatism
Residual astigmatism can still occur despite careful planning and execution. Post-operative evaluation should include:
- Confirmation of stable corneal measurements
- Assessment of toric IOL alignment
If corneal astigmatism measurements remain stable, dilation allows direct visualization of toric alignment relative to the capsular reference marks. When rotation off axis is detected, Dr. Shamie uses astigmatismfix.com to determine whether repositioning the lens will correct the residual error or if further intervention is needed.
Additional options include:
- IOL exchange (if toric power is incorrect)
- Laser enhancement (LASIK or PRK)
- Limbal relaxing incisions
Refractive surgery approaches: Matching modality to error
Astigmatism management also extends to refractive procedures. Available options include:
- LASIK, PRK, and SMILE for corneal-based correction
- EVO ICL (including toric designs) for higher refractive errors
Dr. Shamie generally reserves corneal-based procedures for lower astigmatism corrections (<3.00D), as higher corrections may induce corneal distortion and reduce predictability due to epithelial remodeling.
Higher myopic astigmatic corrections are better managed with the EVO ICL and with the toric option, refractive astigmatism of up to 4D can be corrected also. For hyperopic or mixed astigmatism—particularly at higher levels—refractive lens exchange is often preferred especially if patient is presbyopic already.3
Conclusion
Astigmatism correction in 2026 relies on precise diagnostics, advanced imaging, and a growing range of surgical options. With the tools now available, precise astigmatism correction is not only achievable—it is expected.
As Dr. Shamie emphasized, success depends on a systematic approach: optimize the ocular surface, obtain accurate measurements, select the appropriate intervention, and refine outcomes post-operatively when needed.
