The Road Code requires drivers to be physically, mentally and psychologically able to safely exercise the driving of motor vehicles¹, and these minimum requirements are defined in the Regulation of Legal Qualification to Conduct².

Regarding vision, an assessment of the following parameters² should be made:

- Visual acuity;

- Diplopia;

- Visual field and peripheral vision;

- Color vision;

- Twilight vision;

- Presence or not of progressive ophthalmological disease.

It is also mentioned that attention should be paid to other visual functions that may compromise the ability to drive, such as the presence of glare and the contrast sensitivity. 

In order to carry out the physical and mental evaluation it is advisable that the medical office has certain structural conditions and equipment for this purpose.

Regarding vision, the ophthalmoscope, Snellen type optotypes scale and color vision tests (eg Ishihara, Farnsworth's D15)³, are recommended in order to evaluate the various parameters as follows⁴:

- Evaluation of visual acuity with distant optotype scales, in monocular and binocular vision, with and without correction;

- Evaluation of the visual field and peripheral vision by direct confrontation (allows gross diagnosis of marked changes, as in homonymous hemianopia and quadrantopsias);

- Evaluation of color vision through the Ishihara chart, allowing the identification of the presence of acromatopsia (color vision disorder) or protanopia (vision disorder for red color);

- Assessment of twilight vision by inquiry, when vision changes are suspected in these conditions, such as hemeralopia (night-blindness), mesopic vision (vision disorder with low light) or scotopic vision (vision disorder in twilight lighting).

 

There are several devices that separately test different visual functions, which may be part of the equipment used for vision assessment.

The ability to test all parameters in one device has its obvious advantages. Essilor recently has Visiosmart^®, a visual and digital screening device with a tactile interface.

This device includes the following tests:

- Visual acuity (letters, numbers, Landolt, Snellen, Raskin, being able to test distance vision at 6m, intermediate vision at 67 cm and near vision at 40 cm);

- Astigmatism and latent hypermetropia (for this test a +1 D lens is used); 

- Ametropia (red/green test); 

- Fusion and Stereopsia (depth perception); 

- Forias; 

- Contrast sensitivity (Pelli Robson test); 

- Chromatic sense and color vision (Ishihara test); 

- Glare presence;

- Visual field (luminous dots shown on the horizontal axis at 0°, 60°, 70°, 80°, 90° and 100°).

Regardless of the way the various tests are obtained, and despite the advantages of this new device, it is essential above all the precision in the evaluation of the vision of drivers and drivers candidates.

It is thought that a considerable percentage of road accidents in older people has an ophthamological problem as a cause⁴, so it is also the ophthalmologist’s responsability to act on road safety, ensuring that the assessment is done correctly, and that the person is able to drive safely for yourself and for others.