Cataract Surgery After Refractive Surgery Requires Special IOL Power Calculations

Patients who have corneal refractive surgery and then undergo cataract surgery present unique challenges for the surgeon, particularly regarding expectations of postoperative visual acuity.

Study Design

To develop an overview of evidence-based strategies and considerations for optimizing surgical outcomes in this specific patient population, the authors conducted a systematic literature review of English-language articles published between 1980 and 2023.

Outcomes

The authors identified accurate IOL power calculation as a key challenge for clinicians; studies reported that <70% of eyes achieved refractive outcomes within ±0.5D of target, compared with >80% of eyes that underwent cataract surgery and had no history of corneal refractive surgery. Due to the reduced accuracy of corneal refractive power measurements and challenges in predicting the effective lens position, especially hyperopic ablations, detailed corneal imaging (e.g., tangential curvature maps, epithelial remodeling patterns, Gullstrand ratio) is necessary to improve IOL calculation precision.

Limitations

This literature review identified a current lack of published study data regarding the estimation of IOL calculations after SMILE and hyperopic ablations and the value and reliability of posterior cornea measurement incorporation in IOL calculation. There is a need for prospective studies on the following topics: comparison of the long-term predictability of 4th-generation formulas and wavefront aberrometry; evaluation of the effect of effective lens position and changes in effective lens position over time due to fibrotic changes in the capsule and the magnitude of effect on the refractive outcome; the use of presbyopia-correcting lenses after laser vision correction; and the importance of epithelial mapping and its effect on IOL calculation accuracy.

Clinical Significance

In prior corneal refractive surgery patients, a detailed pre–cataract surgery evaluation should be conducted, including determining the patient’s degree of corneal irregularity, planning the refractive target, and choosing the appropriate IOL based on IOL calculations and the spherical aberration profile. It is important to select IOLs that would neutralize aberration and achieve correction of astigmatism and/or presbyopia. Sometimes, it might not be easy to determine which patients have had subtle ablation or enhancement, and that may lead to formula selection error. Tangential maps are useful for accurate interpretation of ablation patterns.

Financial disclosures: Dr. Amal Alwreikat discloses no financial relationships.