• Suntan beds in tanning salons – goggles should ALWAYS be worn
• Halogen table lamps – if very strong and continually aiming into the eyes
• Light from a welder’s arc – the welder always looks through a mask remember, so bystanders should be extremely cautious.
Prolonged exposure to strong ultraviolet light is the cause of the condition, which also goes under the medical names of ultraviolet keratitis or photo keratitis – keratitis being an inflammation of the cornea.
The term snow blindness is used because it’s people who are in the snow with lots of sunlight who are prone to suffering from it. Snow reflects 80% of sunlight and is increased even more in clear air – for example for every 1000 metres rise in altitude when climbing the intensity increases 10%.
But it’s not only the snow and mountain air that presents a problem when enjoying the outdoors. A walk on the beach on a sunny day will produce around 15% reflection when looking at the sand, increasing to 25% looking into the surf – a flat calm is going to produce even more reflection.
What are the effects of snow blindness?
The effects are quite serious and a great deal of care needs to be taken.
The main problem is the delayed reaction. It can be several hours before any real effects are felt, by which time of course it’s too late. Never has the phrase “prevention is better than cure” been more appropriate.
Several symptoms can be experienced:
• Feeling as if the eyes have grit in them and excessive tears
• Swollen or puffy eyelids
• “Pink” eye along with pain when blinking
• The worst of all – vision degeneration with total blindness, fortunately only temporary
The effect of blindness comes about from damage to the cornea, which is reversible – this indicates that there is some sort of reaction to light rather than to heat from the exposure to sunlight; any heat damage could become partially permanent.
Steps to take in treating snow blindness
Defence survival manuals, hiking and backpacking guides, mountaineering handbooks – they all have instructions on how to deal with an incidence of snow blindness:
• It’s not considered necessary to seek medical advice, but if it’s available and in an environment where medical practitioners are accustomed to treating it, then why not take advantage of their experience.
• Don’t rub your eyes as it just makes things worse
• If pain becomes too unbearable then ibuprofen or its equivalent should be taken
• Cover the eyes as much as possible and try to stop eyelid movement as this only continues to exacerbate the condition, and of course it’s painful
• If total covering is not possible and you need to be on the move then make a couple of very narrow slits in some cloth or even a piece of card and tie round the head.
Check the eyesight twice a day until everything feels okay – always wear polarized sunglasses with good side coverage. In most cases the effects should clear up within a couple of days.
If you can see a therapeutic optometrist, while your eyes are red or in pain a short course of topical steroid eye drops will resolve the condition and get your eyes back to normal quick smart.
How to prevent snow blindness
Wear dark sunglasses that filter out more light with sides that “wrap around”.
When in an environment likely to produce snow blindness, continue to wear sunglasses even if cloudy or overcast.