# The impact of different spectacle designs on the European visual field requirements for driving

## TL;DR

This study shows that certain eyeglass designs can block peripheral vision and affect compliance with European driving visual field standards.

## Contribution

The study identifies how spectacle design impacts visual field testing for driving and highlights gender-related differences.

## Key findings

- Thicker frames and temples in spectacles can compromise compliance with visual field standards for driving.
- Participants with spectacle-related visual field loss had significantly greater vertex distance.
- More missed test points occurred on the side of the dominant eye.

## Abstract

Spectacles can obstruct the peripheral visual field (VF) and interfere with formal requirements for driving. The European VF standards can be assessed with perimetry using the European Driving Test (EDT). This study aimed to evaluate the impact of different spectacles on the EDT, and their compliance with the European VF standards for driving.

This cross-sectional study included 30 participants (15 males and 15 females) with normal VF. Participants underwent binocular EDT perimetry with three different spectacles. The number of missed test points were recorded and the vertex distance (VD), pupillary distance, and eye dominance were measured. Statistical comparisons were conducted using a generalized linear mixed model, with significance set at p < 0.05.

Peripheral VF loss was observed in 11 (37 %) participants (10 males) with spectacle B and in six (20 %) participants (five males) with spectacle C, whereas only one participant had a single missed test point with spectacle A. Participants with spectacle-related VF loss had significantly greater VD than those without. Moreover, there were a higher number of missed test points on the side of the dominant eye.

Spectacles with thin frames and temples had a negligible impact on the peripheral VF, whereas thicker frames and temples could compromise compliance with the VF standards. VF loss was associated with greater VD, which can explain why male participants exhibited more artefacts. These findings emphasize the need to consider spectacle design in fitness-to-drive assessments with perimetry and raise awareness of potential VF restrictions associated with certain eyewear.