Visual Field Limitations Inhibit Driving Ability in Adults With Esotropia

Individuals with esotropia may have a reduced horizontal binocular visual field (VF) that may impair driving ability, according to a study published in Eye. These findings suggest that individuals with esotropia undergo a VF test prior to receiving a driver’s license.

Researchers included a total of 49 participants consisting of individuals with orthotropia (n=10; mean age, 41.90 years), exotropia (n=20; mean age, 40.89 years), and esotropia (n=19, mean age 43.25 years) in the analysis. Participants underwent prism cover tests and monocular and binocular VF assessment. 

No significant differences in binocular best-corrected visual acuity (BCVA) were noted between the groups or in the BCVA of amblyopic eyes between patients with esotropia and exotropia (P =.99). The BCVA of patients with a tropia, however, was significantly reduced compared with patients with orthotropia (P <.01 for both tropias).

Binocular VF was significantly more limited among patients with esotropia (122.8°) compared with individuals with orthotropia (141°) or exotropia (138.3°). A total of 6 (31.6%) participants with esotropia had a binocular VF that failed to meet UK driving standards for licensure.

The horizontal VF extent of the eyes with amblyopia was significantly reduced among patients with esotropia (98.70°) and exotropia (104.75°) compared with individuals with orthotropia (121.00°; P =.004 and P =.045, respectively). 

The researchers stress that individuals with strabismus who meet visual acuity standards for driving may be limited by VF defects. “We found that the horizontal extent of [binocular VF] is significantly smaller and more variable in adults with congenital esotropia,” according to the researchers. “Adults with esotropia applying for a driving license may fall below visual field standard in the UK and in Europe.” 

A failure to assess VF repeatability is an acknowledged limitation to the research.