Authors: Jennifer Ling, Grace Qiao, Alfonso Iovieno, Sonia Yeung.¹

Author Disclosure Block: J. Ling: None. G. Qiao: None. A. Iovieno: None. S. Yeung: None.

Title: Visual Outcomes of Cataract Surgery in Keratoconus Patients in Keratoconus Patients using Toric and Non-Toric Lenses

Abstract Body:

Purpose: This study compares the use of intraocular lens power equations in keratoconus.
Study Design: This is a retrospective case series including patients with keratoconus undergoing cataract surgery between 2000 to 2020. Keratoconus diagnosed by keratometry values and clinician opinion was included.
Methods: This study includes cases of keratoconus diagnosed by keratometry values and clinician opinion from 2000 to 2020. The manifest spherical equivalent, prediction errors and absolute errors were calculated. Descriptive statistics were expressed as mean ± standard deviation.
Results: A total of 160 eyes were included from 101 patients; 136 eyes received non-Toric lenses while 24 eyes received Toric lenses. Most patients had mild disease <48D when stratified by average keratometry values according to Amsler-Krumeisch classification and the mean keratometry value was 46 ± 3D. Eyes with >55D of corneal curvature were significantly more hyperopic following cataract surgery when compared to those with less severe disease (p<0.05). Holladay 1 was the most accurate intraocular lens power equation (-0.04±1D), followed closely by Barrett Universal 2 (0.1±0.6D), and SRKT (-0.2±0.8D). Cataract surgery improved best corrected visual acuity overall, but only significantly in those eyes with <48D and 48-53D. Finally, Toric lenses were largely used in patients with mild disease and the postoperative prediction error was not significantly different from those that received non-Toric lenses. Mean absolute astigmatism was significantly reduced with the use of Toric lenses.
Conclusions: Holladay 1 was the most accurate intraocular lens power equation when used in patients with keratoconus, followed by Barrett Universal 2 and SRKT. Hyperopic surprise was observed in severe keratoconus with >55D. Toric lenses can be used in patients with mild disease.