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Trivia – Fun Facts and Explanations for Eye Nerds

So, its holiday season and a lot of people enjoy going to live trivia or playing trivia at home with family members.

I wanted to make sure you are prepared for potential eye questions that may arise

Fun Fact #1

The red pupil image that shows up on photographs is due to light entering the eye, bouncing off the retina and returning to the viewer

Explanation for Eye Nerds

While we get a red reflex from “the reddish orange background” of the retina, I’ll let you in on a secret.  It’s not really the retina.  In fact, the red reflex we get on a photo (or even the reddish orange color we show you on an Optos image of your eye) is coming from the blood vessels immediately behind the retina.  That’s a different layer of the eye called the choroid which contains anastomoses (big eye word huh!?) of multiple blood vessels which show through the retina.

As for the retina, the retina is actually transparent except for its very bottom layer which is pigmented.  That pigmentation also contributes some of the color we see when looking at an image of the inside of your eye.  Yet most of the reddish orange color comes from blood vessels in the choroid.


Fun Fact #2

More people have brown eyes than blue eyes

Explanation for Eye Nerds

Eye color is not inherited like we all learned in high school biology.  Remember those fruit flies with white eyes, wild eyes, etc. or Mendelian pea genetics?  Yes, autosomal dominant, recessive, chi squares are important in some inheritance, yet eye color is influenced by multiple alleles.  Our eye color shows a multiple allele inheritance.

For the eye nerds, what does that mean?  That means that it’s not quite so simple as exactly “what color do your mom and dad have?”.  Multiple genetic factors influence the color of your iris.  Think of it as iris color (eye color) being more like a rheostat (from no pigment “ice blue” to deeply pigmented dark brown) than as a toggle switch blue or brown.


Fun Fact #3

The first structure you hit if a pen was stuck through your pupil is the lens of the eye

Explanation for Eye Nerds

Having a lens in the eye is called being phakic.  Hence when we do cataract surgery and replace the normal human lens with an artificial “implant” that’s really a false lens.  Therefore, we refer to patients who’ve had cataract surgery as being “pseudo” phakia.  In the old days when we just removed the lens and did not put in an implant, or in some cases where people have trauma and develop a dislocated lens, they are actually called aphakic.  The Latin root “A” means “non” so if you are non-phakic you are also aphakic (and you probably don’t see very well!)

Just a few eye facts to make you ace the trivia competition and be the most educated and valued trivia team member.