Cataract Surgery Does Not Predict Non-Strabismic Binocular Vision Anomalies

Cataract surgery is not associated with postoperative, non-strabismic binocular vision anomalies (NSBVA) in patients with age-related cataracts, according to research published in Ophthalmic and Physiological Optics. Patients with preexisting binocular vision anomalies are likely to experience these anomalies postoperatively. 

Researchers included 51 patients (mean age 70.3 years 74.5% women) who underwent bilateral cataract surgery in the analysis. They performed eye exams and assessed stereopsis, ocular alignment, fusional vergence, vergence facility, and near point of convergence prior to the first surgery and at a follow-up assessment conducted a mean 57.25 days following surgery on the second eye. Investigators also administered the convergence insufficiency symptom survey (CISS) to subjectively assess symptomatology. The primary objective was to investigate the effects of cataract surgery on binocular vision and determine risk factors for post-operative binocular vision anomalies.

Investigators note that one-third of the patients completing postoperative evaluation had NSVBA at baseline, which decreased to 26% following surgery. However, this value failed to achieve statistical significance (P =.48). Following the surgeries, there were a number of participants who converted from a status of NSBVA to normal binocular vision and vice versa, according to the report.

Among the demographics and measurements investigated by the team, only pre-existing NSBVA predicted postoperative binocular vision abnormalities (OR=6.37;95% CI, 1.83-22.14; P <.01). The researchers note that  stereopsis (P <.01),  distance vergence facility (P =.02), and near point of convergence recovery (P <.05), improved significantly following the surgeries, but with small effect sizes (Cohen’s d=0.45, 0.37, and 0.19, respectively). The team observed a significant improvement in CISS score with a large effect size (Cohen’s d=0.83; median change 8.55±10.27; 95% CI, 5.66-11.44; P <.01). 

“[A] pre-existing binocular vision anomaly is the primary independent risk factor for predicting binocular vision anomalies after cataract surgery, while factors including age, sex and interocular differences in vision are not significantly associated with the risk of post-operative binocular vision anomalies,” according to the researchers. “These results suggest that a preoperative case history pertaining to binocular vision anomalies and comprehensive binocular vision assessment should be considered an essential part of the pre-surgical assessment of the cataract patient.”

Study limitations include a high dropout rate and variability in timing of the final follow-up visits.

Reference

Tan Q-Q, Lewis JS, Lan C-J, et al. Cataract surgery is not associated with post-operative binocular vision anomalies in age-related cataract patients. Ophthalmic Physiol Opt. Published online June 12, 2022. doi:10.1111/opo.13012