“Ultimately, this is the art of tailoring treatment to the individual.”
Cataract surgery in patients with keratoconus presents unique challenges, from achieving accurate IOL calculations to optimising visual quality in the presence of corneal irregularities. In this Q&A, Dr Jorge Alio shares his practice pearls, offering key considerations, IOL selection strategies, and surgical techniques to help achieve the best possible outcomes in this complex patient group.
Q: What are the key considerations when planning cataract surgery in patients with keratoconus?
The primary consideration is estimating the potential visual gain following cataract surgery, particularly in patients who have both regular and irregular astigmatism, as is common in keratoconus. The amount of higher order aberrations by corneal aberrometry is an important part of the decision-making process, as well as the presence of corneal opacities. The patient’s visual needs, as well as the presence of associated conditions such as Down syndrome or intellectual disabilities, should also be carefully considered to ensure the best outcome for the individual patient.
Q: What strategies do you use to achieve accurate IOL power calculation in eyes with keratoconus?
I use both the Barrett formula adapted for keratoconus and the Kane formula for keratoconus, which perform similarly. The main challenge lies in accurately calculating toricity, as these formulas cannot fully account for the posterior surface of the cornea. Although the Kane formula is AI-based, in my opinion it requires analysis of larger datasets to improve accuracy, particularly for incorporating toricity values into IOL calculations. I always target to be -1 to -2 D in the spherical estimated residual power to be sure that I don’t run into positive sphere in the refractive error.
Q: How do you approach IOL selection in patients with keratoconus?
I always use toric selections in keratoconus, as most of these cases are adults and the keratoconus should not be progressing. I prefer the Biotech or Zeiss lenses for these cataract cases because they have an unlimited availability of spherical and cylindrical powers on demand. Postoperative rotation of these high cylinder toric lenses is almost non-existing when compared with other posterior chamber lenses. In my approach, higher-order aberrations should be low enough relative to the regular component to justify toric IOL implantation, as very high levels can compromise visual quality despite technically successful surgery.
In patients with Down syndrome or other disabilities, the primary goal is to improve quality of life. This should be approached differently on a case-by-case basis, as in some cases by addressing the high myopia and astigmatism common in advanced keratoconus can significantly improve visual function and binocularity, even when corneal irregularity is marked. Ultimately, this is the art of tailoring treatment to the individual.
Q: Are there any intraoperative or postoperative considerations that you find particularly helpful in optimising outcomes?
I prefer limbal scleral incisions to avoid altering corneal astigmatism when implanting toric high-power cylindrical lenses. In patients with a deep anterior chamber, surgery generally proceeds without difficulty. However, I routinely insert a capsular tension ring, as I have observed zonulopathy and capsular bag instability in some cases, which may be associated with advanced keratoconus. Due to the abnormal elasticity of the cornea, I consider placing a single suture at the incision site to ensure stability. In patients with Down syndrome or other disabilities, where postoperative follow-up may be challenging, I always place a suture to reduce the risk of wound leakage.
Key Takeaways:
- Estimate potential visual gain preoperatively by assessing higher-order aberrations with corneal aberrometry and evaluating for corneal opacities.
- Aim for a postoperative target of −1 to −2 D spherical to avoid positive sphere in the refractive error.
- Select toric IOLs only when higher-order aberrations are low relative to the regular component, as high aberrations can reduce visual quality despite technical success.
- Tailor treatment for patients with Down syndrome or other disabilities, prioritising improved quality of life as the primary goal
Disclosures: Dr Jorge Alio has nothing to disclose in relation to this article. No fees or funding were associated with this article.
Citation: Expert pearls for optimising cataract surgery in keratoconus. touchOPHTHALMOLOGY.com. 3 September 2025.