The Prepper’s Eye

No matter how bad the situation is….you really DO need to see it clearly if at all possible. Taking care of your vision is one of the most critical health preps, but often overlooked. Here’s a quick look at the physiology of the eye, with some notes on prepping to keep a clear view of the world.

Eye design is similar to camera design

To be fair, it’s more like camera design is similar to eyes. That’s where the camera builders got the ideas. Basically, it’s a two-element lens system, with a few bells and whistles.

The front element is a sheet of very tough, clear, protein (with a few cells in there to do maintenance). This cornea protects the rest of the eye and does the bulk of the focusing of light. It can’t adjust its focus to different distances though.

Behind the cornea is a fluid-filled space to allow focusing distance before the light hits the lens. A ring of colored muscle (the iris) overlays the front of the lens to allow you to adjust how much light gets through. Irises determine eye color.

The lens is a a clear, squishy, almost-round structure. It adjusts the focus of the light. You change the shape of your lens to focus on near vs. far objects.

Then there’s a gel-filled space to allow for more focusing distance before the light reaches the sensory structure (the retina) that lines the back of the eyeball.

The incoming light gets crudely focused by the tough cornea, then fine-focused by the lens before being detected at the retina. Image thanks to Artwork by Holly Fischer, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

Wear eye protection to protect the cornea

I used to collect eyes of cattle from the slaughterhouses, to use the tissues in our research. Being as cattle stick their heads down into spiky grasses all day long, cornea injuries were common.

Here’s the thing: Even if the damage to the cornea had long since healed enough to be halfway useful, the cattle would be completely blind in that eye. The retinas disintegrate after fairly short periods in an eye with a corneal injury, and the do not recover. That was enough to sell me on the value of eye protection. Shooting glasses serve pretty well. I use lab goggles, as they’re good for many kinds of hazards and are comfortable over my normal glasses.

Sure, you’ve got a second eye. You do use them both to get an accurate judge of distances, though. Also, there’s a chunk of your visual field that’s only covered by one of your eyes. Better to just keep them both working.

Minor corneal scratches irritate above their weight class

Another common sort of corneal injury is minor scratching of the corneal surface. Some minor irritant like a bit of dust is not enough to damage the tough protein of the cornea, but it can damage the single sheet of live cells that sit on that protein sheet and are bathed by the tears. 

These little corneal scratches won’t cause lasting damage, but they cause way more trouble than seems right. First, the inflammation scatters enough light that the eye won’t have clear vision until it heals.  What if that’s your shooting eye?

To give you a sense of scale, my sister was effectively blind in one eye for a full week after rubbing her eyes when she had a bit of popcorn salt on her fingers. Yeah, one stupid salt crystal was all it took. Also, it feels pretty miserable; more like the surface of the eye was made of sandpaper than you had a tiny scratch.

The message here? Well, it reinforces the need for eye protection when there’s blowing grit or other potential debris. Also: Rinse not rub. Holding the head sidewise and prying the lids open with fingers if needed, you can gently squirt good, clean (emphasis on the clean) water over the corneal surface. If you’ve got some sterile saline on hand (I hope so), it’s even better than water.

If you’re rinsing out particles you can be done when the particles are out. If it’s a chemical wash-out, it’s recommended to keep rinsing for fifteen minutes if possible.

Snowblind: A corneal burn

UV radiation can burn the cornea. Most often this comes at high altitude (less of the UV light’s been filtered out by atmosphere), but bright sun on reflective surfaces is the main ingredient. Welding without a helmet and very bright artificial lights can do the same thing. 

This again is a surface injury. It makes the eyes useless for several days and is irritating as all get-out. Normal treatment also includes antibiotic drops, but my understanding is that that’s an insurance policy. I’m not a physician however.

The best defense is good sunglasses when in bright reflective environments. A face mask with eye slits would restrict vision, but might be better than risking snow-blindness. A less potent but far more comfortable fix would be to put black patches right under the eyes. Camou makeup, sports eye-black, even a spot of black tape or smear of coal would help. Do keep the coal dust out of the eyes though.

Also, be careful with the optics when the sun is up. You do Not want to track that rifle scope across the sun!

When your eye is not so eagle to start with…

Prescription glasses are expensive. If you really need glasses, not having them is catastrophic. If you can afford a backup pair, even in cheap frames and minus all the cool lens coatings, it’s worth keeping those close. Home in a drawer is not as good as in your nearest emergency bag. If that’s hard to swing, here are some other options:

• Keep the most recent old prescription in that bag instead.
• If your needs are not too far from a cheap pair of reading glasses, keep a pair of those. Try some and see.
• Keep a spare frame that fits your current lenses. Lenses themselves seldom break and can often be reseated.
• Zenni.com  and no doubt other online sellers may provide a backup pair of glasses far cheaper than your normal pair. (We have no financial interest with Zenni; we’ve just had good outcomes with them.)

Keep an eye on these ideas too

If you regularly wear contacts, please consider the difficulty of keeping good hygiene for them in an emergency. Backup glasses are better than an eye infection/inflammation any day of the week.

Are you a good candidate for Lasix or other corrective surgery? A one-time up front cost that makes you no longer need correction is a great prep.

The lens of the eye is one of the few tissues that continue to grow as we age. The bigger it gets, the harder it is to get it to round up enough to focus on near objects. That’s why everyone has more trouble with close vision as we age. If you do not need glasses, but are in midlife, you can protect against the eventuality with a pair of reading glasses. That prep will allow you to continue to do close, fine work much later in life. You do not want to have to try to stitch up something (be it clothing or a wound) by feel and fuzzy shapes. On the bright side — if you’re near-sighted, you may *lose* your need for glasses for close work.