Career & Educational Resources
If you know someone who is considering the careers of Optometry or Opticianry, we are available to visit with them. Eyecare is an enriching healthcare profession, allowing each of us to connect personally with our patients and to serve them to the best of our abilities.
Don’t Make Light of the Blues
Do you get tired eyes from working at a computer? Beartooth Vision Center carries Blutech lenses, which protect eyes from high energy visible (HEV) light, increase eye comfort, and reduce computer, hand-held device and fluorescent light glare. These lenses may also reduce sleeping problems that are related to prolonged exposure to electronic devices.
The world has many types of electromagnetic energy, from tiny gamma rays to radio waves that are longer than a football field. Short wavelength, high energy gamma waves are extremely damaging to human tissue, but dissipate in a very short distance. By contrast, long wavelength, low energy radio waves can travel through the atmosphere to the other side of the earth.
Imagine the entire electromagnetic spectrum is the length of a football field, with the longest radio waves on the left goal line and the shortest gamma rays on the right goal line. The part of the spectrum that is visible to the human eye would be about 2 feet wide, located on the right 40 yard line. This 2 foot wide human vision zone on a 300 foot wide electromagnetic energy spectrum football field is what we will concentrate on in this article.
The visible light within these 2 feet is made of the familiar rainbow spectrum from longest wavelength red through orange, yellow, green, blue, indigo, and ending with the shortest wavelength color violet. Just beyond violet is the ultra (“above”) violet (UV) part of the spectrum, not visible to our eyes, but of great significance to our skin. Just beyond red on the lower end of the visible spectrum is infra (“below”) red (IR) light. As the longest visible wavelength, red light is least affected by distance and visual obstructions such as fog and darkness. Because of this, fire engines have red flashing lights and red jet lights are visible from many miles away in the night sky. Violet, on the other hand, would be a completely wrong color for these purposes. It dissipates far too quickly to be seen at any meaningful distance. A purple sign can be a challenge to see from even a short distance away.
The higher energy part of the visible light spectrum begins at the blue portion of the spectrum and is known as high energy visible (HEV) light. By far, the largest source of blue light is the sun. We do not know how damaging the combination of the sun plus electronic blue light sources is to our eyes and health. In normal doses, HEV light plays important roles in our lives. The balanced exposure we get from the sun and regular incandescent lightbulbs helps to establish and maintain our sleep – wake cycles, as well as influencing hormonal balance, cognitive, and psychomotor aspects of our bodies.
Like many things in life, however, a thing that is healthy in small amounts can be dangerous in large doses. This may be a very real possibility with HEV light. Recent research studies suggest that frequent computer and cell phone use as well as the widespread replacement of standard incandescent and halogen light bulbs with HEV – intensive LED, “cool” fluorescent, and CFL lighting may increase our long term risk of retinal conditions such as macular degeneration. Over-exposure to blue light may also cause disruption of a person’s wake – sleep cycle, evidenced by problems sleeping at night after spending hours on a computer or a hand – held device.
If you would like to see a Blutech lens for yourself, stop by Beartooth Vision Center for a demonstration and further information.
Really, Really Cool Eye Facts
Eyes are amazing examples of God’s handiwork. Consider the following:
If you were to stand on a mountaintop in perfect darkness, your pupil (the hole in the middle of the iris, which is colored part of your eye) would enlarge to allow as much light as possible to enter your eye, and you would be able to see a single candle flame that is 30 miles away. Using your 6 million sensitive central vision cone photoreceptors, you would be able to discern the 2 separate headlights of a car about 2 miles away from you, but the most distant object you can possibly see is above your head: the 1 trillion stars of the Andromeda galaxy, located 2.6 million light years away. (That’s more or less 15,300,000,000,000,000,000 miles). You would see Andromeda best by using an old astronomer’s trick of looking just beside it, not directly at it, so that you would use some of your 135 million rod retinal photoreceptor cells that are used for night vision. You will need to use more than one of your rods to see Andromeda, though, because 66 rods can fit in an area the diameter of a single human hair.
As an owl hooted while on the mountain, you would be hearing the only bird that can see the color blue, and it is likely on the lookout for a moving mouse, which it can see 150 feet away. You effortlessly coordinate the 6 movement muscles around each of your eyes to turn them toward the owl, and the lens inside each eye adjusts to bring him into stereo and depth focus. The owl must turn his entire head to see you, because he has no muscles with which to turn his eyes. As you blink to see him better, the owl will go out of your view for 1/15th of a second as your eyelids obscure your line of sight, but every time you blink (15 – 20 times per minute or 28,800 times per day) you are bringing fresh tears and nutrients to the clear part of your eyes, called the cornea. Those new tears are also washing away the pollen that blows into your eye as you brush by a nearby pine tree. If the pollen were to tickle your nose, it would be impossible for you to sneeze without closing your eyes. If your cornea were to get a minor scratch from a pine needle while on your mountain expedition, with proper care, it will likely heal within a few hours. This is a good thing because the cornea is the only tissue of your body that has no blood vessels to help it to heal and it is important that it mend quickly, because it protects the rest of your eye from infection.
As you amble back down the mountain, you muse on the old saying that the eyes are the islands of the brain. This means that as part of your central nervous system, your eyes serve as the cameras for your brain. It also means that along with your brain and spine, the retina (the photoreceptor “film” that lines the inside wall of your eye) will not heal if badly injured. You are reminded that 80% of your memories are visual and that 90% of learning in a classroom is through your eyes. Long before your first day of school, your eyes were one of the first parts of your body to develop inside your mother’s womb, beginning just 2 weeks after your conception. The various combinations of the 256 unique features of your iris (the colored part of your eye) make you far more unique than the 40 features of your fingerprint.
At the bottom of the mountain, you wipe the sweat from your eyebrows, which have served as a sponge, preventing the salty sweat on your forehead from getting into your eyes. You have unknowingly dropped a couple of your eyelashes while on the mountain, but that does not concern you because if they were lined up end to end, you will shed about 98 feet of eyelashes over your lifetime. You have plenty more to spare. You glance at your blue eyes in the rear view mirror of your car. Until about 6 – 10,000 years ago there were only brown eyed people in the world, and you share a common ancestor from that time period with every other blue eyed person in the world. Once home, you close your eyes and go to sleep. Your eyes have earned their rest.