The Pot of Gold at the End of the Rainbow

Have you ever been told that there’s a pot of gold at the end of a rainbow?  You may be skeptical, but it is absolutely true.  You see, rainbows don’t exist in the natural world.  Instead, they exist as an image created within our eyes, thanks to a wonderful and delicate structure called the retina.   It is the retina that is responsible for all the colorful splendor of our visual world, a treasure indeed worth its weight in gold.  A closer look at the retina reveals one of the most remarkable structures in our body.

Form Meets Function

To understand how the retina creates the colors of the rainbow, we have to look at the intricacies of its design.  The retina is a thin structure that lines the inside surface of the eye, similar to the rubber lining on the inside of a basketball.  The retina has a surface area of a silver dollar, and packed within that space are 150 million cells called photoreceptors.  It is upon this sheet of photoreceptors that the light from our world is projected.  Together, these retina cells interpret light of different colors, shapes, and movement, converting them into nerve impulses.  These nerve impulses are then sent to the brain, where higher-level processing turns the images into meaningful information.

How Important is the Retina?

When it comes to quality of vision, the retina is like the Supreme Court… it makes the final decision.  That is why the human body is designed to deliver more blood flow to the retina than any other part of the body, proportional to its weight.  It is also why the retina is completely protected from an immune response, lest the damaging effects of inflammation disrupt the very tiny and fragile components of vision.  Even the structures surrounding the retina, such as the eye socket, eyelids, and eye wall, are specifically designed to protect the retina from injury.  Our bodies have devoted tremendous resources to ensure that our retina functions properly.

 

A Window to the Soul

Despite its privileged status in the body, the retina can still be affected by a wide range of illnesses.  Some of these diseases are specific to the retina, such as age-related macular degeneration and retinal detachment.  Interestingly, the retina can also be damaged by conditions that affect the entire body, such as diabetes or high blood pressure.  In fact, examination of the retina frequently reveals undiagnosed bodily illness.  It is not uncommon for the eye doctor to be the first to catch cancer, a stroke, or an infection before the patient has other symptoms.

 

Caring For Your Retina

Since the retina is so important to vision, it is critical that we take steps to protect it.  As with other organ systems, control of blood sugar, blood pressure, and cholesterol are critical to long-term retinal health.   Stopping smoking and wearing Sunglasses with UV protection are also very important.    Additionally, extensive research has gone into vitamin supplementation for retinal health.  At this time, vitamins are only proven to benefit patients with age-related macular degeneration.  However, there are several formulations of vitamins on the market today that have theoretical benefits to retinal longevity in the healthy consumer.  These supplements typically contain anti-oxidants and nutrients such as lutein, zeaxanthin, and omega-3 fatty acids.  Similarly, a balanced, low-fat diet with plenty of green, leafy vegetables should adequately provide the necessary retinal nutrients, without the need for supplements.