People with binocular vision disorders were found to have lower satisfaction with contact lenses. Photo: Getty Images.

Symptoms associated with binocular vision disorder may be linked to contact lens (CL) discomfort and consequential higher rates of CL dropout. Researchers recently confirmed that binocular vision disorders can contribute to CL dissatisfaction independently of CL discomfort.

The study, based at the School of Optometry and Vision Science, University of New South Wales, Sydney, Australia, assessed 76 dry eye patients while wearing their habitual CLs. It measured symptoms of CL discomfort and binocular vision disorders with the Contact Lens Dry Eye Questionnaire-8 (CLDEQ-8) and Convergence Insufficiency Syndrome Survey (CISS), respectively. A comprehensive binocular vision assessment was also performed. In addition, the researchers measured CL dissatisfaction from CL discomfort and binocular vision disorders with the Ocular Surface Disease Index (OSDI) based on reported correlations with the CLDEQ-8 and CISS. They categorized patients in terms of CL discomfort (≥12 on CLDEQ-8) and binocular vision discomfort.

Key findings were noted in patients with CL discomfort, including significantly shorter comfortable wearing times, a higher proportion of meibomian gland dysfunction and shorter fluorescein tear breakup time.

The researchers found that those diagnosed with binocular vision disorders scored higher than those without disorders for the OSDI (25.1 vs. 10.7) and CISS (18.7 vs. 11.9) but not the CLDEQ-8. Those categorized as having CL discomfort scored higher than those categorized as having no CL discomfort for the OSDI (19.0 vs. 9.3) and CISS (16.1 vs. 11.0). There were no significant interactions between binocular vision status and CL comfort status for any questionnaire.

Because significant differences were not found within binocular vision status, and there was no significant interaction between binocular vision status and CL comfort status for OSDI scores, the researchers believe that the significantly higher OSDI scores in those diagnosed with a binocular vision disorder cannot be attributable to CL discomfort. They proposed that the most likely cause is symptoms from the binocular vision disorder, indicating that CL dissatisfaction from binocular vision disorders is independent of CL discomfort.

Since the highest mean score on OSDI was achieved in those with both a binocular vision disorder and CL discomfort, they suggested that the effect on CL dissatisfaction may be additive when both conditions are present.

The study concluded that, in addition to routine CL and ocular surface assessments, dissatisfied CL wearers should have a binocular vision workup to determine whether a vision disorder is contributing to CL dissatisfaction.

Tilia D, Bakaraju RC, Apser LJ, Papas EB. Association between binocular vision disorders and contact lens dissatisfaction. Optom Vis Sci. 2021;98(10):1160-8.