Firstly we must understand what the eyes are and how they function. The eyes are mostly comprised of water; therefore, it can easily be seen (no pun intended!) how frozen temperatures can adversely affect the eye. The vitreous humor (the actual fluid portion of the eye) is kept warm by the ambient body temperature and also the vessels that supply the eyes with blood. In periods of extreme cold, this temperature can be greatly reduced. Blinking is one of the actions of the eye that both moistens it and also allows accessory muscles to give off heat that keep the eyes warm. In addition, the closed and clenched eyelids can help to hold in some of the heat and protect against cold.
Now, here in Montana goggles (at some point) are a must. I prefer lightly tinted wraparounds that allow outward “breathing” of the eyes (yes, the eyes do give off heat and moisture) and that are fog-resistant. These goggles lock in the eyes’ ambient heat and protect them from the gale force winds and frigid temperatures. When you are looking around outside (no pun intended, once again!) and the temperature is -25 degrees Fahrenheit or colder, you better be sure to have eye protection.
There are many different brands. I do not have a personal favorite. Just take note of this: the tinting on your goggles must afford UV protection (400 is the guideline you can work off of, indicating the percent of UV rays shielded). This factor is important because if they are just tinted without providing the protection from ultraviolet rays, the eye and the retina can suffer damage. This is because tinting in itself (because of the darker view) allows the pupil to expand. Such will let in more light; however, more UV rays also penetrate, and this can lead to retinal damage and/or snow blindness. Make sure they have UV protection (minimum 100%).
When it is cold, but not below freezing, I highly recommend sunglasses. The sun is lower in the sky in the winter, and this allows for the human eye to pick up more light, especially in the form of the aforementioned UV rays. Once again the same principle applies as with the goggles. The sunglasses should have (as your guideline) a 400% UV protection factor. Remember, these will help immensely against snow glare and potential snow blindness. Among the problems besides direct or snow-reflected light are reflections from icy or shiny spots when you’re hiking or climbing.
Snow blindness occurs when a partial (or permanent) injury to the retina by prolonged or intense light exposure renders the eyes incapable of normal vision. Prolonged light exposure would include long hikes without any eye protection as mentioned in the previous paragraphs. In a survival situation where there are no sunglasses in the survivor’s first aid pack, this can (and often does) occur in flat, open areas when crossing in the daylight hours during peak sunlight exposure times.
Signs and symptoms of snow blindness are as follows:
- The sensation of sand/grit within the eyes, accompanied by pain and soreness both in and over the eyes. This pain is exacerbated when you move your eyeballs.
- Runny/watery eyes
- Redness of the eyes and the rims/edges
- Headache (increased duration usually increases the severity)
- Increased light sensitivity/pain in the eyes from the increased light
Treating Snow Blindness
The immediate first-aid actions to be taken are to remove your eyes from the light source/get out of the light. Taking shelter in a darkened area can do this. Another thing to do is to cover both eyes with a dark or thick cloth. You can substitute anything that will interfere with exposure to the light…bandages, dark glasses, a knit hat doubled up and pulled over the eyes…use your imagination. Of course, before you do this, make sure you’re in a safe area that you can rest and alleviate the exposure of the eyes to any light.
In this vein one can see that it is best to travel in either the backcountry of the Alaskan Yukon or in the ice flats of the Dakotas in the winter months with a field-partner. One can assist the other in time of trouble and thereby cut down on the risk of something else happening. With few exceptions, all types of winter tragedies and trauma can be prepared for to a certain degree with a minimum amount of funds and efforts.
To conclude, the eyes are very sensitive and precious instruments that need to be maintained and protected. Should you suffer from any eye injuries as mentioned in this article, I highly recommend having an eye exam after you return home to make sure that no further complications may be underlying. Plan and prepare, and in this manner you stand the best chance at making your outdoor excursions productive and enjoyable. You’ll be able to rest assured that you have taken steps to take care of trouble before it turns to tragedy. Have a good one, and “keep an eye out” for one another!