Visual Outcomes of Cataract Surgery in Patients With Keratoconus Using Toric and Non-toric Lenses

PURPOSE: To compare the accuracy and outcomes of differ- ent intraocular lens (IOL) power calculation formulas in eyes with keratoconus undergoing cataract surgery with toric and non-toric IOLs. METHODS: This was a consecutive retrospective case series study including patients from the Cornea Service at the De- partment of Ophthalmology and Visual Sciences at the Univer- sity of British Columbia, Vancouver, Canada, from 2000 to 2020. Keratoconus was diagnosed based on corneal topography and clinician opinion. Patients who underwent topography-guided photorefractive keratectomy, intracorneal ring segments im- plantation, or corneal transplant were excluded. The manifest spherical equivalent, prediction errors, and median absolute errors were calculated. Descriptive statistics were expressed as mean +/- standard deviation. RESULTS: There were 160 eyes from 101 patients; 136 eyes received non-toric lenses and 24 eyes received toric lenses. Most patients had mild disease (< 48.00 diopters [D]) when stratified by steep keratometry values. Patients with severe disease (> 53.00 D) were significantly more hyperopic follow- ing surgery (P < .05). The Barrett Universal II (0.26 D, inter- quartile range [IQR] = 0.4), Holladay 2 (0.31, IQR = 1.2), and SRK/T (0.42, IQR = 0.86) formulas had the lowest median ab- solute error. The postoperative prediction error following to- ric lens insertion was not significantly different than following non-toric lens insertion, and the mean absolute astigmatism was significantly reduced with toric lenses. CONCLUSIONS: The Barrett Universal II, Holladay 2, and SRK/T were the most accurate IOL power calculation formu- las in patients with keratoconus undergoing cataract surgery. Hyperopic surprise was increased in severe keratoconus. To- ric IOLs may be considered in patients with mild keratoconus. [J Refract Surg. 2023;39(5):319-325.]