Eye Anatomy-How the Parts of the Eye Work

 

The human eye is a highly specialized organ. The eye has the ability to receive visual images, which are then transmitted to the brain. How the eye works is fascinating. After the brain, the eye is the next most complex organ in the body.

1.The Cornea is the clear “window” found at the front of the eye. The cornea is made of a tough, transparent tissue. This tissue keeps dirt, germs, and other particles from getting into the eye. Some of the sun's damaging ultraviolet (UV) light is prevented from entering the eye by the cornea.

2.The pupil is the black dot at the center of the eye. It is an opening at the center of the iris through which light passes. 

3.The Macula is a small but critical area in the center of the retina. The macula manages translating light into images needed to clearly see the details of objects in central vision.

4.The Iris is the colored part of the eye. The primary job of the iris is to regulate the amount of light that reaches the retina. It does this by controlling the size of the eye's "window," or the pupil. 

5.The lens of the eye (or crystalline lens). This transparent structure is on the inside of your eye. It is a natural lens found behind the iris. The lens changes its thickness and curvature, allowing the eye to adjust focus on objects from varying distances. If the natural lenses in the eye are irregularly shaped, your eye doctor may prescribe glasses or contact lenses to correct vision.

6.The Optic Nerve is a bundle of about 1.2 million nerve fibers that send visual information to the central nervous system (brain).

7.The Retina is a key connection between the light that enters your eyes and the images you see. Special cells called photoreceptor cells in your retina react to light and pass signals to your brain that let you see what is around you. 

8.The Sclera is most times known as the "whites" of the eye, covering more than 80% of the eyeball's surface. It has grooves that help properly attach the eye to the tendons to supply stability and protection while staying flexible. This allows the eye to move and track objects as needed.

9.The Optic Disc is where the nerve fibers of retinal ganglion cells join and mark where the optic nerve begins. The optic disc also serves as the starting point for major blood vessels that feed the retina.

Path the light takes to create an image:

Step 1: Light enters the eye through the cornea.

Step 2: The light passes through the pupil, which is the opening in the center of the iris. The pupil adjusts in response to the intensity of the light by getting larger or smaller.

Step 3: The lens focuses the light onto the retina by adjusting its shape to bend and refocus the light a second time, ensuring the clearest image of what you are looking at.

Step 4: The light is then projected onto the retina Once the light is focused on the retina, the light-sensitive layer of tissue at the back of the eye. The retina converts the light into electrical signals. The nerves in the retina collect all the electrical impulses.

Step 5: The optic nerve transmits visual information to the brain through the optic nerve at the very back of the eye up to the occipital lobe in the back of the brain. The brain then interprets these signals as an image.

This is just a condensed version of how the eye works. There are more micro components within the eye to aid the major parts of the eye listed above.

Watch this video from The American Academy of Ophthalmology https://youtu.be/Sqr6LKIR2b8

Sources:

www.britannica.com

www.aao.org

www.nei.nih.gov

www.optometrists.org

www.clevelandclinic.org

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What Do Eye Experts Wish Patients Knew About Their Eye Health

 

At the 2023 American Society of Retina Specialist meeting in Seattle, Washington, eye experts were asked "What do you wish your patients knew about eye health?"

A majority of the experts that were asked believe that most patients feel their vision is important, but they take it for granted. Many people assume that if their vision seems fine, they have no eye health issues. However, this is a misconception.

People with seemingly good vision can have hidden problems. Problems that may have no symptoms, until irreversible damage is done.

Experts strongly recommend regular dilated examinations with an eye healthcare, professional and a fundus photo to ensure overall ocular health. Dilating the pupil allows more light into the eye and allows your doctor to see inside the eye. The most widely accepted way to check for eye diseases is a dilated eye exam. Early detection of disease is important. Catch them when they are easy to treat. Treatment is more likely to be successful when detected early.

The doctor will evaluate these functions during a dilated eye exam:

• Visual acuity

• Visual field

• eye muscle function

• Pupil response

• Tonometry test

Another tool for early detection the doctor may recommend for patients to have is an optical coherence tomography (OCT). This test is used to generate a picture of the back of the eye.

Catching eye diseases early can: 

• Help prevent or delay vision loss. 

• Preserve your vision and quality of life.

• Allow for earlier and more effective treatment. 

That is why most eye experts recommend patients have regular eye exams and cannot stress it enough. Your risk for eye disease will determine how often you should get a dilated eye exam. Talk to your doctor about what is right for you.

If you are:

• Over age 60

• African American and over age 40

• Have a family history of glaucoma

• Have diabetes or high blood pressure

Ask your doctor how often you need an exam. Most of these people should get a dilated eye exam at least once a year.

Sources:

www.ophthalmologytimes.com

www.modernretina.com

www.techtimes.com

www.ama-assn.org

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Is your make-up bag carrying risks?

 

Makeup has been around for thousands of years and is used in almost every culture in the world. From tribal to the Hollywood style known today. Ancient Romans and Greeks to ancient Egyptians used kohl to line their eyes and made their own natural creams.

Eye makeup is the perfect breeding ground for bacteria, it can become contaminated with common germs, normally found on eyelashes and eyelids, so eye makeup brushes or eyeliner will pick up bacteria during use. Then it is returned to the moist dark environment of its container. The container before opening is free of contamination, frequent use can transfer bacteria that is on your skin and eyes to the makeup. Over time, the contaminated brushes lead to a buildup of bacteria in the cosmetic container. This increases the chance of infection with each use of the product.

Another source of infection is when you share cosmetics. Even if you are sharing brand new cosmetics, the person you are sharing with may have an eye infection and share the infection with you also. 

Other issues that come from makeup besides infection:

• scratched cornea

• Lash loss

• Conjunctivitis

• Blepharitis

• Allergic reactions

• Toxic heavy metals

• Blurry vision

• Block glands

Contact lens wearers are susceptible to even more eye problems. Some eye makeup products may contaminate your contact lenses.

Top tips for using eye makeup safely:

• remove makeup before bed

• Throw away old makeup more than three months old

• Don’t share makeup or brushes

• Be village in with contact lenses

• Track the date you open your makeup

• Pick oil-free products to reduce block glands

• Clean or replace your brushes regularly

Sources:

www.clevelandclinic.org 

www.visionsource.com

www.URMC.Rochester.edu

www.allaboutvision.com

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#DrClaudiaWendel

#PittsburghOptometrist

#PittsburghEyeCare

How to safely watch a solar eclipse

 

On Saturday, October 14, an annular ("Ring of Fire" as if the moon is outlined with flames) solar eclipse will crossover North America, Central America, and South America. An annular solar eclipse happens when the moon passes between the sun and the earth. While this is an exciting and unique experience, it is crucial to prioritize safety when seeing an annular eclipse.

During an annular eclipse, it is never safe to look directly at the sun without eye protection specifically designed for solar viewing. Failure to protect the eyes while looking at the sun during a solar eclipse can result in "eclipse blindness" or solar retinopathy, causing damage or destruction to the cells in the retina. 

 Everyday sunglasses, even very, very dark ones are not safe for looking directly at the sun. Specialized solar eclipse glasses are about 100,000 times darker than regular sunglasses. Solar eclipse glasses should be labeled as IS012312–2 international standard compliant. Eclipse glasses and handheld viewers should always be inspected before use. If torn, scratched, or otherwise damaged, discard the device. 

When viewing the sun through a camera lens, binoculars, or a telescope using a polarizer does not offer enough protection, it is best to use a special-purpose solar filter. Viewing any part of the bright Sun through a camera lens, binoculars, or a telescope without a special-purpose solar filter secured over the front of the optics will instantly cause severe eye injury. By design, these lens-based devices intensify light rays, damaging both the solar filter and your eyes.

Another concern with a solar eclipse is to protect your skin from invisible UV rays. If you are viewing the eclipse, you may be in the sun for hours. Remember to apply sunscreen and wear protective clothing to prevent skin damage. Sunburn is the skins reaction to UV radiational damage to the outermost layers of skin. Sun tanning is a sign of the skin reacting to potentially damaging UV radiation by producing more pigmentation. The pigment known as melanin provides the skin with its color and protects the skin against the sun’s rays.

The solar eclipse will only be 30% visible in southwestern Pa. at starting at 11:53 AM for a duration of 2 hours and 40 minutes.

 

Sources:

www.planetary.org

www.nasa.gov

www.aao.org

www.aas.org

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#DrClaudiaWendel

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What is that ring around your cornea?

This condition, called corneal arcus sometimes referred to as Arcus Senilis, are lipid (fatty) deposits that appear first as arcs then as rings on the outer region of the cornea. The cornea is the clear dome shaped window in the front of the eye. These rings are usually gray, white or blueish giving the illusion of two different eye colors and are usually opaque. Corneal arcus consists of cholesterol, phospholipids and triglycerides.

The cloudy ring may seem like it would make it harder for you to see, however, it doesn’t affect your vision, it is not dangerous, but it won’t go away either. It is just a benign sign of aging. Arcus is common in older adults. 

When it does occur in patients before the age of 40 there is more of a concern. Blood tests are definitely recommended to rule out lipid and cholesterol abnormalities. There is a chance of what is known as familial hyperlipidemia, a disorder that is passed down through families. It causes very high levels of “bad” cholesterol and is linked to an increased risk of heart disease. Corneal arcus in only one eye could be a sign of decreased blood flow to the eye without the arcus due to carotid artery disease or ocular hypotony. You always want to consult a medical professional to confirm there are no underlying conditions. Many times we see not just sight threatening conditions, but sometimes life-threatening that can be seen in the smaller parts of the eye before they are found in other parts of the body.

Sources: 

www.webmd.com. 

www.clevelandclinic.org 

www.ncbi.nlm.nih.gov

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#DrClaudiaWendel

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#PittsburghOptometrist

 

Gr8 Eye Movement

 

Gr8 Eye Movement is a campaign that aims to raise awareness of retinal diseases that cause significant vision loss. The GR8 Eye Movement establishes a time to prioritize eye health by designating the eighth of every month as a day to check eye health.

Award-winning actress, dancer, choreographer, singer-songwriter, director and producer, Debbie Allen has joined with Prevent Blindness, and Regeneron for the Gr8 eye movement to encourage those who are at risk of or affected by retinal diseases like:

• Wet age-related macular degeneration (wet AMD). Wet age-related macular degeneration is when new abnormal blood vessels grow into the macular. These vessels leak blood or fluid. Scarring of the macula occurs and rapid loss of central vision.
• Diabetic, macular edema (DME). Diabetic macular edema is a complication of diabetes. Retinopathy is an accumulation of leaked fluid.
• Diabetic retinopathy (DR). Diabetic retinopathy is a disease that damages the blood vessels in the retina, leading to bulges, leaking, and reduced blood flow.

95% of adults are at risk for retinal diseases and don’t even know it. "Diabetes has ravaged my family: my father, my grandfather, my aunts and uncles," says Allen.

The main goal of this campaign is to make more people aware of retinal diseases. Educate those who are at distinct risk of developing these diseases. It is critical for people who are from communities of color, those over the age of 60, those living with diabetes, or those at risk of developing diabetes. 

You can join the movement, by visiting www.gr8eyemovement.com. Where you can:

• Access, resources, and information to make eye health a top priority.
• Find useful tips, including how to use an Amsler grid to detect any vision changes. The Amsler grid is a diagnostic tool that aids in the detection of visual disturbances. The grid is made up of horizontal and vertical lines used to check a person's central visual field. The grid was developed by a Swiss Ophthalmologist, Mark Amsler. 
• Understand when to make an appointment for eye care. 
• Sign up to receive emails with helpful reminders.

This campaign is named Gr8 Eye Movement to use the 8th day of the month as a reminder day, but if it is the 8th, the 18th or any other day and you suspect you are having difficulty with your vision make that appointment today. Don’t wait!

#Gr8eyemovement

#visionsourcesouthhills

#DrClaudiaWendel

#PittsburghOptometrist

#PittsburghEyeCare

Sources: 

www.preventblindness.org

www.regeneron.com

www.ophthalmologytimes.com. 

www.looktoyourfuture.com

www.macularsociety.org

The Effect of Stress on the Eyes

 

It is common knowledge that stress has serious effects on the body. Some people may experience sleep issues, headaches, digestive issues, and cardiovascular issues, but eye health and vision can also be affected. Issues that are due to the adrenaline hormones and cortisol (the stress hormone) are released during times of stress or anxiety, the eyes remain dilated during stressful situations, placing added pressure on the eyes.

While stress is a cause of vision loss, vision loss generates more stress. Stress affects the visual capabilities in different ways, including: 

• Dry eye

• Double vision

• Eyestrain

• Blurred vision

• Eye twitching

• Dark Circles

Scientific links between stress and vision:

• The stress hormone (cortisol)

• Flight or fight

• Oxygen levels

• Inflammation

When the brain perceives an increase in stress levels, it releases cortisol, the hormone that is responsible for initiating your flight-or-fight response. Causing the heart rate and blood pressure to increase. Stress also forces you to breathe faster, shallow breaths lower oxygen levels. Lack of oxygen to the eyes may result in hazy vision, redness, and eye discomfort early. Extreme long-term cases can lead to corneal ulcerations. Diseases of the visual system like optic neuropathy, and glaucoma are side effects that an increase in cortisol can have.

Most stress-related vision problems are temporary if recognized early before severe damage is done, and symptoms will disappear as soon as you begin to relax. The best way to avoid these stress-related vision issues is to learn how to de-stress, some ideas to help combat your stress:

• Exercise

• Meditate

• Deep breathing

• Eat a balanced diet.

• Write in a journal.

• Get adequate sleep.

Taking steps to control the stress you feel now will help avoid problems in the future. Not just to eye health, but overall health.

Just Chill!

Sources:

www.cnet.com

www.stress.org

www.optometrists.org

#visionsourcesouthhills

#DrClaudiaWendel

#PittsburghOptometrist

#PittsburghEyeCare