Drinking **alcohol** significantly affects the driver's **vision**. Even when consumed in small amounts, alcohol is distributed throughout the body via the bloodstream and has a direct impact on the brain and eyesight. This can lead to a series of visual impairments that are dangerous when driving.

- **Tunnel vision**: Alcohol reduces the ability to see what is happening on the sides, limiting the driver's field of vision. This is known as tunnel vision, where only what is directly in front is clearly perceived, while objects on the sides become blurry or invisible.

- **Difficulty seeing signs and traffic lights**: Under the influence of alcohol, it is more difficult to distinguish traffic signs and traffic lights, which can lead to critical driving errors.

- **Problems judging distances**: Alcohol affects distance perception, making it more difficult to judge the proximity of other vehicles or objects on the road.

- **Glare**: Drivers under the influence of alcohol are more prone to being dazzled by the lights of other vehicles, which can cause accidents.

Therefore, even with low blood alcohol levels, the driver's vision is affected, increasing the risk of accidents.