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The Retina: How They Function in our Eyes

When we consider vision and how we see and interpret the world around us, we rarely consider how our eyes function as a resource to our brain. How exactly are our eyes capable of sending those electrical pulses to the brain so we can understand and interpret  what we are seeing?

The retina plays a big role in that. This blog will tackle what the retina is, how it helps us see, and common vision problems that can arise from the retina.

 

 baby blue eyes

What is the retina?

The retina is a thin tissue layer (only about .5 to .1 mm thick!) located in the back of each our eyes near the optic nerve. It is composed of alternating layers of cells in order to best interpret and direct the light coming in through our eyes. It’s an important part of our eye that assists in processing light and sending signals to our brain to help translate what we see. It covers a large section (nearly 65%) of the interior surface area of our eye, which allows us to experience peripheral vision with a total vision field of approximately 200 degrees.

 


What creates the retina?

The retina has several parts that work together to direct and interpret light:


Photoreceptor cells – These cells detect color and light intensity and are responsible for converting light energy into electrical signals that travel through the optic nerve to our brain. In human eyes you can find two different kinds of photoreceptor cells:

  • Rods – There are approximately 120 million rod cells in each eye. They are light sensitive and low resolution, and they see in black and white. Rods are, for the most part, situated in our peripheral vision. They help us see and spot various light intensities. Fun fact: rods have a hard time seeing reds, which limits our  night vision and is why it’s easier for us to pick out blues and yellows in darkness vs. reds. Red is also the light color used when you don’t want to ruin your ‘night vision.’
  • Cones – There are approximately  6 million cone cells in each eye. They provide a sharper resolution and greater color sensitivity. Cones are commonly situated around the eye’s macula and fovea region.

 

eye cells colorfulFovea – This region is found in the back, central part of the retina. Consider this a small ‘wrinkle’ in the retina that is the single point of our sharpest vision and highest color perception.

 

Optic nerve – The optic nerve is a bundle of nerve fibers that carries electrical signals to the brain. It is attached to the back of the eye and forms a natural blind spot that we largely are capable of ignoring.

 

 

Damage to the retina

The retina is vital to the vision process, so damage to it can lead to permanent vision loss and even blindness. Common retinal conditions include:

 


Retinal detachment
– This occurs when the retina is dislodged from the back of the eye and results in loss of vision and necessitates surgery to adhere the retina back to the eye.


Vitamin A deficiency
– Vitamin A assists in the development of photopigment, which is critical for the photoreceptors in our eyes. A deficiency leads to visual degradation over time.

 

Retinitis pigmentosa – This is an inherited disorder where a person is unable to keep photoreceptor cells over time. This leads to difficulty seeing at night and a loss of peripheral vision over time.

 

digital retinal photograph inner eyeMacular degeneration – This is the leading cause of blindness in aging Americans over the age of 65. It is mostly defined by slow, consistent vision loss over the years. There are two forms of this disease — both wet and dry. See our previous blog post [LINK] for more information.

 

Diabetic retinopathy – Diabetes damages the retina by damaging the blood vessels that supply blood to the eye. Swollen and bleeding blood vessels in the eye can result in vision loss and eventual blindness in the eye.

 

Tips to protect the retina

As we age, it is hard to completely stop vision loss; however, there are steps we can take to slow the process and keep our eyes healthy and strong. Consider these preventative tips to help keep your retina healthy, particularly as you find yourself getting older.

 

Maintain a healthy diet Vitamin A, C and E, as well as mineral zinc have been shown to help prevent and slow the progression of macular degeneration. Lutein and zeaxanthin are both carotenoids with antioxidant aspects that have been shown to influence a healthy macula region.

  • Many of these nutrients can be found in fruits and vegetables, specifically leafy greens and yellow/orange colored varieties
  • Nuts and seeds are also a good source of nutrients

 

Strengthen your eyes – Simple, everyday eye exercises can help reduce eye strain and keep the muscles in and surrounding your eye healthy and strong. Take five minutes a day to look away from a screen and move your eyes up, down, and side to side with blinks in between each movement.

 

Keep those eyes protected Be aware of hazards to your eyes and take steps to keep them safe. Don’t look directly into bright lights, lasers or beams, and wear protective gear when in hazardous areas.

 

Take time to relax In today’s society, we always seem to be moving somewhere for one reason or another. To keep some of the strain off your eyes, be intentional about taking 10 minutes each day to close you eyes and take time for yourself.

 

If you have questions about the retina and what it means for your vision, don’t hesitate to reach out to our office. Williamson Eye Institute specializes in retinal and corneal care and will work with you to develop an appropriate plan of action.

 

Web Logo-02At Williamson Eye Institute, we are committed to preserving and protecting our patients’ eye health throughout their lives. To find out more, visit our website or call our office to schedule a personal consultation. You can also find us on Facebook, Twitter and LinkedIn.