Hate driving at night or light too bright? It is a well known fact that most accidents with fatalities occur at night. With the nights drawing in, there are a few of us who begin to suffer with night vision impairment also referred to as night blindness. Before I go on let me differentiate impairment and blindness.
There are only a few of us who strictly suffer from night blindness. Lets go back in time to our Biology lessons. The back of the eye (retina) contain rods and cones that once stimulated by light send electrical impulses to the brain…. that’s how we see! Night vision is mainly performed by the rod receptors. Night blindness may be a result of various conditions that affect the efficiency of the receptors. These conditions may include vitamin deficiency, glaucoma (nerve damage) and Retinitis Pigmentosa (genetic) to name a few.
However, the majority of us will experience night vision impairment at some point in our lives. This may present as glare, haloes, temporary blindness, confusion or simply blurred vision.
So what causes glare and haloes?
- The pupil gets bigger due to reduced light at night, we have more aberrations / distortion in our vision due to the ‘reduced depth of focus’.
- An uncorrected prescription can also cause problems when night driving in particular.
- Eye disease that involves the cornea or the lens within the eye (cataract) may also be a cause.
- Brighter headlights using high discharge lamps (xenons)
- The least obvious? Dirty windscreens.
To sum up, how do we deal with night vision impairments?
- Have a sight test – A sight test can identify many eye diseases that can be treated. A large proportion of night vision impairment is easily dealt with a pair of spectacles to correct any uncorrected refractive error with an anti reflection coating.
- Clean your windscreen – Dirt and debris can scatter inbound light making the light source appear ‘brighter’! Any imperfections / cracks on the windscreen will also have a similar affect.
- Clean your headlights – Be considerate to other people on the road. Most high discharge lamps (xenons) have their own wash system to help clean the lens surface.
- Adjust your mirrors – Most modern cars come with a self adjusting rearview mirror and others have a manual option to adjust the rear view mirror to its night setting.
- Avoid looking directly at headlights – With increasing age, it takes the eye longer to recover from direct exposure to bright light.
Any questions, feel free to drop by for some tea and a chat. Safe driving!