In patients undergoing toric lens implantation, prior laser assisted in situ keratomileusis (LASIK) or radial keratotomy (RK) surgery, keratoconus, and higher astigmatism may increase the odds of a suboptimal refractive outcome, according to research published in Clinical Ophthalmology.
Researchers from the Wilmer Eye Institute, in Baltimore, Maryland, analyzed 446 eyes that underwent toric lens insertion by the same surgeon between 2016 and 2020. They noted preoperative exam findings, biometry, and 1-month and 3-month post-operative vision and refraction. The study considered reviewed charts cases if uncorrected distance visual acuity (UDVA) was worse than 20/40, if spherical equivalent (SE) was greater than 1 diopter (D) off target, or if the cylinder was more than 1 D off target.
After toric lens implantation, 93.7% (n=343) of eyes achieved UDVA of 20/40 or better, 92.7% (n=306) were within 1 D of target SE, and 90.9% (n=300) were within 1 D of target cylinder. UDVA cases had significantly more eyes with prior LASIK (21.7% vs 7.0%, P =.01) and keratoconus (8.7% vs 0.6%, P <.001) compared with controls. More SE cases had prior radial keratotomy (RK) (8.3% vs 0%, P <.001) and keratoconus (12.5% vs 0%, P <.001) compared with controls.
More cylinder cases had prior LASIK (30.0% vs 8.7%, P <.001) and greater mean astigmatism (2.3 vs 1.5 D, P =.02) compared with controls. A higher percentage of cases in all 3 analyses had greater toric cylinder power (T5-T9) than controls.
Factors such as age, sex, eye laterality, axial length, anterior chamber depth, lens power, dry eye, anterior basement membrane dystrophy, and Fuchs’ endothelial dystrophy were not significantly associated with poorer outcomes.
“Our study found that most patients undergoing toric lens implantation have favorable outcomes as measured by UDVA, residual SE, and residual cylinder. Prior LASIK or RK surgery, keratoconus, and higher astigmatism may increase the chance of a suboptimal outcome,” according to the researchers. “By recognizing these factors, surgeons can better counsel patients about expectations after surgery.”
Study limitations include its retrospective nature and the exclusion of some patients from the SE and cylindrical analysis.
Gauthier A, Awidi AA, Noble PM, Daoud YJ. Factors predictive of refractive error after toric lens implantation. Clin Ophthalmol. Published online June 26, 2023. doi:10.2147/OPTH.S407414