ipRGC

Our eyes are amazing and we now realize that they are for so much more than just vision.  In 2001 Intrinsic Photo Receptive Ganglion Cells were discovered.  In addition to the rods and cones which enable us to see colors and focus, as well as to make out shapes and contrast in dim lighting, these ipRGC’s have nothing to do with our vision. 

87% of our sensory information received is by sight, 50% of our brain is used for vision and yet within our eyes are also these ganglion cells, many of which we still don’t know what functions they perform.  We now do know that the ipRGC’s send information to the part of our brain associated with short term memory as well as our circadian rhythm.  These ganglion cells absorb light, especially blue light which is essential for the entrainment of our circadian rhythm (see blog on Circadian Rhythm). 

There is so much more to learn about our eyes and how they influence our health, with the discovery of these ipRGC’s we have gained the understanding that our eyes are essential for many of our biological functions. 

Aging Eyes

As we age our eyes age and change as well.  I first noticed a change in my vision when I could no longer see the hole in a needle to thread it.  I am now learning that this and other vision differences are a natural part of aging. 

The pupil doesn’t adapt as quickly to changes in lighting and there is a decrease in the amount of light that reaches the retina.  This can cause falls as eyes don’t adjust to changes in light levels as we transition from room to room or to and from the outdoors.  This can also cause a disruption in our circadian rhythm resulting in sleep disturbances.  Aging eyes also experience a loss of contrast sensitivity and depth perception which can affect many areas of our lives.  From how we move through rooms to the ability to eat when the food is light colored and plates are in the same color hues.

“At age 60 our eyes require 3 times as much light as they did at 20 and 2 times as much as when we were 30.  Most of the lighting guidelines where written with the 30 year old user in mind.”  Paul Eusterbrock, President of Holkotter International.

Eye diseases are also more prevalent in older adults:  cataracts- loss of clarity, glaucoma-loss of peripheral vision, macular degeneration- loss of center vision and diabetic retinopathy.  Lighting can either increase or decrease these symptoms, the individuals sensitivities and needs need to be assessed and considered.

Lighting in the environment can be critical for health, safety and the ability to live independent lives for all of us as we experience aging eyes or are dealing with an eye disease.