Kiwis are being warned glare, bright light and changing driving conditions can lead to dangerous vision issues while driving over summer.
The warning comes from Specsavers optometrist Celeste Raisbeck who says while vision problems can affect drivers at any time of the year - day or night - driving at night or twilight is often far more dangerous due to difficulty in seeing clearly.
She is urging drivers to stay safe over summer. "Good vision is fundamental to safe driving. Most of the information we need for driving we get through our eyes so it's vitally important for people to make sure they can see properly before getting behind the wheel.
"Your vision can change at any time or at any age and lead to trouble reading road signs, seeing clearly at night, gauging depth perception, being affected by glare or identifying objects in the distance."
Raisbeck says the most common causes of vision problems on the road - and how to manage them before they become an issue - include the following:
Glare in bright sunlight
Glare can make it hard to see in the sun, so for the best kind of protection buy sunglasses with polarised lenses as they provide superior vision in bright light, by eliminating 99.9 per cent of horizontal glare. They also provide 100 per cent ultraviolet (UV) protection.
If you are struggling to see through glare even with sunglasses, it could indicate other eye issues, including early cataracts or a corneal abnormality causing a slight haze that is worse in sunshine.
An optometrist can prescribe lenses to help make glare less of a problem. Tinted lenses, polarised and photochromic lenses - which react by darkening when the light is bright - may be particularly helpful.
If you need lenses for driving, bear in mind that photochromic lenses will not darken effectively inside modern cars as their windscreens contain a filter which blocks UV light as it is the UV in sunlight that makes photochromic lenses darken.
Problems with glare often worsen with age and are sometimes associated with the development of cataracts. If glare is a concern, make sure you mention this to your optometrist.
Sun-strike
Sun-strike can occur at any time during the day, but is most likely at sunrise or sunset when the sun's rays hit the windscreen at a low angle creating a blinding glare. This can be very dangerous for drivers.
Despite sun-strike related accidents being most common in winter, caution should be practised throughout the year.
A simple solution is to wear polarised sunglasses. Good-quality polarised eye wear will reduce the effect of sun-strike.
Driving at night and twilight
One of the difficulties driving at these times is glare from headlights, brake lights and reflective surfaces. Glare can be worse for those wearing prescription glasses, which is why it's important to speak to an optometrist if you are wearing glasses while driving at these times.
They can talk about adding an anti-reflective (AR) coating to your glasses like Ultraclear to help reduce glare. An AR coating works by eliminating light reflections from the front and back of eyeglass lenses.
High-index lenses are often used for stronger prescriptions, which often means more light is reflected off the surface of the lens. When reflection is eliminated from lenses, it means more light is available to the eye, making clear vision easier. This is especially useful for night driving.
Light sensitivity
Sensitivity to light - also referred to as photosensitivity or photophobia - can be a symptom associated with a range of eye issues. If you are experiencing photosensitivity, you may also notice other symptoms - including discharge from eyes or headaches.
Most commonly, it is associated with inflammation and infection, but it is best to consult your optometrist, who can help determine the underlying cause of photophobia.
If you have blue or green eyes you may be more sensitive to light than people with brown eyes because darker-coloured eyes contain more pigment, offering natural protection in bright sunlight and other harsh conditions.
Protecting eyes with sunglasses can help alleviate these symptoms. Optometrists may recommend polarised sunglasses or special contact lenses designed to help people cope with light sensitivity.
Says Raisbeck: "The simplest thing you can do to protect yourself against the impacts of the sun while driving is to have your eyes regularly tested to ensure they are fit to drive. Also keep a spare pair of polarised sunglasses in the glove box, so there are no excuses for being caught behind the wheel without them."
To book an appointment, or for more information, visit: www.specsavers.co.nz/stores.