Car collisions tied to inferior visual field in patients with advanced glaucoma

01 Jul 2017
Car collisions tied to inferior visual field in patients with advanced glaucoma

In patients with advanced glaucoma, the incidence of motor vehicle collisions with oncoming cars is associated with the inferior visual field, a recent study has found.

Researchers assessed the relationship of specific visual subfield defects with collisions with an oncoming car, under the controlled conditions provided by a driving simulator (DS; Honda Motor), in patients with advanced glaucoma. The inferior visual field, as well as age and visual acuity, was found to be an important factor linked to the ability to safely navigate the said specific collision scenarios.

The study included 43 normal participants and 100 patients with advanced glaucoma (mean deviation <‒12 dB in both eyes; Humphrey Field Analyzer 24-2 SITA-S program), of whom five were excluded after experiencing simulator sickness during the main test.

There were two scenarios in which oncoming cars turned right crossing the driver’s path. Researchers then compared the binocular integrated visual field (IVF) in the patients who were involved in collisions and in those who were not.

Multivariate logistic regression analysis was performed. Collision involvement was the dependent parameter, whereas age, visual acuity and mean sensitivity of the IVF subfields were the independent parameters.

In one or both DS scenarios, there were significantly more collisions among advanced glaucoma patients vs normal participants (p<0.001). Patients with advanced glaucoma who were involved in collisions were older (p=0.050), had worse visual acuity in the better eye (p<0.001) and had lower mean IVF sensitivity in the inferior hemifield, both 0° to 12° and 13° to 24°, vs those who were not involved in collisions (p=0.012 and p=0.034).

Collision involvement significantly correlated with reduced inferior IVF mean sensitivity from 13° to 24° (p=0.041), in addition to older age and lower visual acuity (p=0.018 and p<0.001), based on logistic regression analysis.

These findings may help in crafting guidelines for safe driving for patients with glaucoma and for the development of clear warning systems to encourage risky drivers to reconsider driving and avoid potential motor vehicle accidents, researchers said.

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