Lorraine Williamson
In Spain, nearly 80% of the population has some form of vision problem. Given that vision is critical for safe driving, the DGT (Directorate-General for Traffic) has provided essential recommendations for drivers with visual impairments to enhance road safety.
Vision statistics in Spain
According to a recent “Vision in Spain” report, 80% of Spaniards experience vision issues, with common conditions being:
- Presbyopia (42%)
- Myopia (39%)
- Astigmatism (39%)
- Hyperopia (18%)
Considering that drivers receive about 80% of driving-related information through their eyes, addressing these issues is crucial for road safety.
Key recommendations for drivers
1. Use corrective eyewear
Always use glasses or contact lenses as prescribed to ensure optimal vision while driving. For those needing reading glasses, progressive lenses are advisable to easily read dashboard information like speedometers and GPS.
2. Sunglasses for comfort
Wearing sunglasses can prevent glare and make driving more comfortable, especially in bright conditions.
3. Avoid night driving
If you struggle with night vision, such as difficulty distinguishing signals or judging distances, it is best to avoid driving at night or in poor lighting conditions. Plan your trips to avoid adverse weather conditions like rain or fog.
4. Speed management
Reduce speed to compensate for reduced visual fields at higher speeds. This allows more time to process visual information and react appropriately.
5. Medication and vision
Certain medications can affect your vision. Follow your doctor’s advice, and avoid night driving if your medication impacts your visual acuity.
6. Post-examination caution
If your pupils are dilated during an eye exam, wait until the effects wear off before driving to avoid impaired vision.
7. Familiar routes
Stick to familiar and less congested routes to minimise the complexity of driving tasks.
Also read: Remove sunglasses when entering a tunnel
Understanding visual challenges
Driving demands constant attention to central and peripheral visual fields under varying lighting conditions. Dr. Nouzet, in the “Manual on Neurology and Driving,” explains that processing these visual inputs requires integrating various types of information (position, size, colour, movement) to form clear images in the brain. Visual impairments can significantly hinder this process.
Critical visual abilities for driving
- Visual Acuity: The sharpness of vision to perceive details.
- Visual Field: The total area visible when looking straight ahead.
- Contrast Sensitivity: The ability to distinguish an object from its background.
These abilities can be affected by eye diseases (cataracts, glaucoma) or systemic conditions (diabetes). Reduced capabilities can endanger the driver and others on the road.
Regulatory standards and recommendations
Spanish regulations permit driving with binocular visual acuity of 0.5 or higher, with or without correction. However, achieving the best possible vision through corrective lenses, even if not legally required, is strongly recommended. Night driving and low-visibility conditions further reduce visual acuity, making it essential to maintain good contrast sensitivity to detect road signs, pedestrians, and other vehicles.
Night vision and glare
Aging increases the prevalence of night vision issues and glare sensitivity. Short-term blindness from glare, lasting 3-5 seconds, can be hazardous, especially in older adults or those with cataracts. Many drivers avoid night driving to mitigate these risks.
Peripheral vision
A broad visual field is more critical than visual acuity for perceiving the driving environment. Conditions like retinopathy or macular degeneration can impair the visual field, making driving unsafe. Even without pathology, vehicle structures can obstruct vision. Regular use of mirrors and head movements can help, especially for monocular vision drivers. Understanding how increased speed reduces the visual field underscores the importance of driving slower.
Alcohol and vision
Combining night driving with alcohol consumption exacerbates the decline in visual and motor skills, further impairing peripheral vision and reaction times. As blood alcohol levels rise, so does the risk of visual impairment and delayed response to visual stimuli.
Spare glasses
It is good practise to keep a spare pair or glasses in your car. In the event something happens to your glasses or contact lenses when driving, an extra set will allow you to continue on your journey safely.
Also read: You could be fined if you use speed radar jamming devices