Clinical outcomes of Toric IoL long term follow up and predictors of clinical outcome
Authors: Harika Kollipara  , Mathew Kurian  , Luci kaweri  
Published: September 2024

Background: Cataract surgery is a common procedure, and correcting astigmatism during surgery is crucial for achieving spectacle independence. Approximately 20 -30% of cataract patients have significant corneal astigmatism. Toric intraocular lens (IOLs) will correct astigmatism by having different powers in different meridians and are designed to minimize postoperative rotation. Proper patient selection and precise placement are essential for success. Study aim and objectives: To study the long term outcomes of intraocular toric IOL implantation after an uneventful cataract surgery. The study objectives to assess the role of posterior corneal astigmatism, corneal biomechanics, and surgically induced astigmatism on the long-term outcomes of toric IOLs. Outcomes measured include best-corrected visual acuity, residual astigmatism, and IOL rotational stability. The roles of surgically induced astigmatism (SIA), posterior corneal astigmatism, and corneal biomechanics on long-term toric IOL outcomes will be evaluated. Methods: Detailed preoperative planning, including refractive state analysis, corneal topography, and keratometry, is necessary. Various marking tools and techniques are employed to ensure accurate IOL placement. Results and Implications: The study evaluated the effectiveness of toric IOLs in managing pre-existing corneal astigmatism during cataract surgery. The mean uncorrected distance visual acuity (UDVA) at the end of one year was 0.18 ± 0.16 logMAR, and the mean best-corrected visual acuity (BCVA) was 0.05 ± 0.09 logMAR, with 92% of patients achieving a UDVA of 20/40 or better. The mean rotational stability of the toric IOLs, evaluated using iTrace, was 6.03 ± 4.43 degrees, with a maximum rotation of 20 degrees, and 15% of patients had a rotation of more than 10 degrees. Pre-operative mean refractive astigmatism was -2.21 ± 1.12, which improved to -0.71 ± 0.57 at the end of one year. The study also found a statistically significant correlation between deformation amplitude and surgically induced astigmatism (SIA). Overall, toric IOL implantation proved to be a reliable method for correcting corneal astigmatism during cataract surgery, resulting in improved visual acuity and stability. The study explores the effectiveness of different toric IOL models and the impact of misalignment. Proper surgical techniques and postoperative management are crucial to minimize complications and achieve optimal visual outcomes. Conclusion: Toric IOL (Intraocular Lens) implantation is found to be an effective and predictable method for managing pre-existing corneal astigmatism, producing better visual outcomes in the post- operative period with good rotational stability. The study emphasizes the influence of corneal biomechanics on surgically induced astigmatism (SIA) and suggests that outcomes could be improved by incorporating these biomechanical factors into calculations for toric IOLs. Additionally, the research highlights the need for further studies on the relationship between deformation amplitude and refractive outcomes after toric IOL surgery, as well as the importance of considering corneal biomechanics in pre- operative assessments.