Vision Problems and Eye Health

How Do the Eyes Work?

To understand how the eyes work, it's helpful to compare the eyes to a camera. Cameras use a lens and film to produce an image, and in a way, so do the eyes.

Light comes in through the cornea, a clear tissue that covers the front of your eye. The pupil is the dark spot in the middle of your eye. It works like a camera shutter, controlling the amount of light that enters our eyes. When it's dark, the pupil dilates, or widens. When it's bright, the pupil gets smaller. Surrounding the pupil is the iris. This is the colored ring of muscle fibers that help the pupil change size.

When you look at an object, light rays enter your eyes. These light rays are bent and focused by the cornea, lens, and vitreous. The vitreous is a clear jelly-like fluid that fills the inside of your eye. The lens' job is to make sure the rays come to a sharp focus on the retina at the back of the eye. Think of the retina as the film in the camera. It's lined with light-sensitive cells, called photoreceptors, that capture, upside-down, the images in our visual field. The sensitive macula, critical for sharp focus, is the most active part of the retina. A healthy macula helps us read small print and see the images in our direct line of vision. When light rays reach the retina, they're converted into electrical pulses that travel through the optic nerve to your brain. It is there that the image gets flipped right-side up.

Vision Screening Guidelines

Guidelines for Adults

• At least one test between ages 20 and 29 and at least two between ages 30 and 39
• Vision tests every two to four years between ages 40 and 65 and every one to two years after age 65.

Guidelines for Children

• Children five years and younger should have their eyes checked each time they see their pediatrician. Teens should be examined once a year.

If you are experiencing any vision problems, it's a good idea to get checked more often.

Protecting the Eyes & Vision

While we can't control the risk factors that make us more vulnerable to vision problems, it's important to exercise caution:

• Know your family's medical history;
• Protect your eyes with sunglasses that absorb 100 percent of damaging ultra violet rays;
• Stay away from cigarettes which contain chemicals that can damage the eyes; and
• Eat a healthful diet.

Types of Vision Problems

It's normal for our vision to deteriorate as we age. Here are some very common vision problems that can usually be corrected with glasses or contacts:

• Farsightedness. This occurs when you can see well at a distance, but not close up.
• Nearsightedness. This is also called myopia. It occurs when you can see well close up, but not at a distance.

There are some vision problems that are much more serious and can even lead to blindness.

If you have a family history of eye disease, you'll have a higher risk of developing vision problems. You may also have other risk factors like previous eye injury, premature birth, diseases that affect the whole body, like diabetes, high blood pressure, heart disease, or AIDS. The only way for you to know for sure if you have serious eye problem is by having an eye exam given by an Optometrist (O.D.) or an Ophthalmologist (M.D.).

• Glaucoma. This occurs when the pressure of the fluid inside your eyes damages the fibers in your optic nerve, and causes vision loss. If left untreated, you can lose your eyesight altogether.
• Cataracts. A cataract means a 'clouding' of all or part of the normally clear lens within your eye, which results in blurred or distorted vision.
• Conjunctivis. This is commonly known as Pink Eye. It is caused by an inflammation of the conjunctiva. This is the thin, transparent layer that lines the inner eyelid and covers the white part of the eye. The inflammation is usually caused by a virus, and will resolve without any treatment. But, sometimes pink eye is caused by a bacterial infection and will require antibiotics.
• Eye Floaters. These may look like small dots or lines moving through your field of vision. They're actually tiny clumps of gel or cells inside the vitreous fluid in the eye. They may be a sign of retinal detachment and you should call your doctor right away.
• Macular Degeneration. This results from changes to the macula portion of the retina. The macula is responsible for clear, sharp vision. This condition can cause a blind spot in the middle of your sight line.
• Retinal Tears and Detachment. These affect the thin layer of blood vessels that supplies oxygen and nutrients to your retina. Initial symptoms are eye floaters. This condition must be treated immediately. If it isn't, it can lead to permanent vision loss.

Early detection is key to fixing problems with your sight. Don't take your eyes for granted. Get them checked regularly, and tell your doctor if you notice anything unusual.

Sources

Age Related Macular Degeneration. Bethesda, MD.: National Institute of Health, 2009. (Accessed October 18, 2009 at http://www.nei.nih.gov/health/maculardegen/index.asp.)

Vision Not Improved By Surgery for Complications of Age Related Macular Degeneration. Bethesda, MD.: National Institute of Health, 2008. (Accessed October 18, 2009 athttp://www.nei.nih.gov/news/statements/surgery_amd.asp.)

Vision Problems. Atlanta, GA.: A.D.A.M., 2008. (Accessed October 18, 2009 athttp://www.nlm.nih.gov/medlineplus/ency/article/003029.htm.)

HealthiNation offers health information for educational purposes only; this information is not meant as medical advice. Always consult your doctor about your specific health condition.

Reviewed by: Dr. Supriya Jain, Dr. Preeti Parikh and Dr. Holly Atkinson

Last Review Date: 08/29/2012

Host Reviewer: Dr. Roshini Raj

Author: Ms. Audra Epstein

Copyright © 2013-2014 HealthiNation, Inc. All rights reserved.

What Are Those Spots In Front Of My Eyes?!

They're kinda like little bugs flying around, except there are no bugs there! Lots and lots of little spots in front of your eyes all of a sudden, and it seems like they are always RIGHT in front of your vision when you are trying to read. Or it feels like there's a spot just outside your field of view--is that the bug? You just can't shoo it away.





They're floaters!

Wait...what the heck's a floater, anyway? Well, a floater is a little speck of protein debris in the vitreous jelly, the jell that fills up the middle of the eye. The vitreous jelly (you may have heard it called vitreous humor in school) is very important for the development of the eye until we're about 2 years old. After that point it's really just there to cause mischief. One of the mischievious things it does is shrink.

The thing that make the vitreous a gel is the same thing that makes Jello a gel. There's a microscopic protein skeleton and as we get older that skeleton collapses upon itself. Little areas that used to be just barely microscopic are now just dense enough to be macroscopic. They form a little clump and VOILA...a floater.

So you've got floaters, what do you do about them? In time your brain will learn to ignore them. They become like background visual noise and your brain just ignores them, just like the old fashion elevator operator who didn't hear the elevator music any more because it was always there!

For some more information check out this Eyemaginations video here. If you DO have floaters make sure to get them evaluated at Skyvsion Centers.

Who Made That Eye Chart?

Buying eyeglasses in the 1700s was tricky: 

you had to diagnose the problem yourself and then pick the correct lenses. Some vendors  helped customers along by scratching ages onto their spectacles, so that a 40-year-old would be steered to “40” lenses­ — the assumption being that everyone’s vision deteriorated at a similar rate as they grew older

But these shortcuts no longer sufficed in the mid-19th century, as doctors began to understand that patients needed bespoke lenses.

At a hospital in the Netherlands, Dr. Franciscus Donders devised a method for diagnosing vision problems: he would ask people to gaze at a chart on a distant wall and report what they could see. Apparently too busy to make the chart 

himself, he enlisted the help of a colleague, Herman Snellen.

Snellen first printed up a chart with dingbats — squares, circles,

 plus signs — of various sizes, but that proved to be a bad idea. 

“When you look at a symbol, how do you describe it?” says 

August Colenbrander, a scientist at the Smith-Kettlewell Eye

 Research Institute who has researched the history of the eye

 chart. (It was probably easy to cheat, too.) In the end, Snellen 

realized that letters would work best.

The chart spread all across Europe, an instant hit. “The first big 

order was from the British Army, in 1863 or so,” Colenbrander

 says. “Obviously the soldiers who fired their muskets had to be 

able to see.” Soon after that, printers everywhere copied it. A

 low-tech solution to a complex problem, the chart has remained

 popular because it was cheap and easy to use. But widespread 

reproduction and success are two different things. The EFPTOZ 

chart (pictured here) has practically become iconic, undermining

 its medical value, Colenbrander says. A recognizable eye chart is

 not a very useful one.

By PAGAN KENNEDY

May 24, 2013

The Meibomian Gland Dysfunction Epidemic

Our Meibomian glands are just inside our eyelashes. They produce the oil or lipid part of our tears. The oil in our tears stabilizes the surface or the tears and prevents rapid evaporation. An abnormality in this layer cause a type of Dry Eye.

A video about your meibomian glands Video Link Click Here

Most of the eye doctors, and especially our own Cleveland Dry Eye experts here at Skyvision Centers, believe that we are now having an epidemic of Dry Eye and especially Meibomian gland disease. This is due at least in part to major changes in the U.S. populations intake of Omega-3 fatty acids over the last 50 years. These changes came about from government subsidies of corn, which is now the feed of choice for everything from cows to fish! This change in the diet of livestock and fish from grass and algae to corn is contributing to the frequency and severity of Dry Eye.

What can we do to reverse this? Well, we probably can't change U.S. farm policy overnight, but the doctors at Skyvision are convinced that everyone, especially anyone with Dry Eye, should be taking a high quality Omega-3 fatty acid nutritional supplement. For example, Doctors Advantage brand names "Eye Relief" or "Omega Shield" have the right combination of ingredients to help. Our doctors can advise you of what may be best for you.

Our vision, comfort, and even quality of life starts on the surface of the eye with our tear film and we would like to help you enjoy and feel your very best!

Glucosamine Supplements Tied to Risk of Eye Condition

By Denise Mann
HealthDay Reporter

THURSDAY, May 23 (HealthDay News) — Glucosamine supplements 

that millions of Americans take to help treat hip and knee osteoarthritis 

may have an unexpected side effect: They may increase risk for

 developing glaucoma, a small new study of older adults suggests.

Glaucoma occurs when there is an increase of intraocular pressure 

(IOP) or pressure inside the eye. Left untreated, glaucoma is one 

of the leading causes of blindness.

In the new study of 17 people, whose average age was 76 years, 

11 participants had their eye pressure measured before, during and 

after taking glucosamine supplements. The other six had their eye 

pressure measured while and after they took the supplements.

Overall, pressure inside the eye was higher when participants were 

taking glucosamine, but did return to normal after they stopped taking 

these supplements, the study showed.

“This study shows a reversible effect of these changes, which is 

reassuring,” wrote researchers led by Dr. Ryan Murphy at the 

University of New England College of Osteopathic Medicine in 

Biddeford, Maine. “However, the possibility that permanent damage 

can result from prolonged use of glucosamine supplementation 

is not eliminated. Monitoring IOP in patients choosing to supplement 

with glucosamine may be indicated.”

Exactly how glucosamine supplements could affect pressure inside the

 eye is not fully understood, but several theories exist. For example, 

glucosamine is a precursor for molecules called glycosaminoglycans,

 which may elevate eye pressure.

The findings are published online May 23 as a research letter in 

JAMA Ophthalmology.

The study had some shortcomings. Researchers did not have 

information on the dose or brand of glucosamine used, and they did 

not know how long some participants were taking the supplements.

Duffy MacKay, vice president for scientific and regulatory affairs at

 the Council for Responsible Nutrition, a Washington, D.C.-based

 trade group representing supplement manufacturers, said the findings 

don’t mean that people should stop taking the supplements.

“This research letter raises questions and introduces a hypothesis 

that should be explored further, but the small number of cases

 investigated and the [fact that] researchers did not count capsules or control 

for dose or intake or duration of use of glucosamine provide extremely limited 

evidence of harm,” MacKay said.

“This study should not change consumer habits; however, individuals

 with glaucoma or ocular hypertension who are taking glucosamine 

should let their doctor know so that the appropriate monitoring of 

intraocular pressure measurements can be done to identify any 

changes,” he said.

MacKay concluded: “The good news is that increased IOP was 

reversible. So if you take the product, and your IOP goes up, then you 

can stop taking the product to see if it returns to normal.”

However, previous studies have raised questions about whether 

glucosamine supplements provide any health benefit to consumers. 

A large recent study concluded it had no healing effect on arthritic pain.

The potential relationship between glucosamine and glaucoma is new

to Dr. Scott Fudemberg, a glaucoma surgeon at Wills Eye Institute, 

in Philadelphia. “The mechanism about how people can develop 

glaucoma isn’t completely understood, so how the supplements 

may play a role isn’t completely understood either,” he said.

While the study found an association between taking glucosamine 

and increased eye pressure, it didn’t establish a cause-and-effect 

relationship.

The best thing that anyone can do to preserve their vision is to get

regular eye exams, Fudemberg advised. “Glaucoma can be treated 

with medications, lasers and/or surgery,” he said. “These findings 

pose a question about whether oral glucosamine can raise intraocular 

eye pressure, but it doesn’t provide an answer. More research is 

now needed before any conclusions can be drawn.”

FYI: Can A Bionic Eye See As Well As A Human Eye?

It's the difference between a grainy black-and-white film and HD.

By Alyssa Brewer

What's New in Eye Care . . . . 

Previously blind patients who receive the recently FDA-approved Argus II bionic eye system will regain some degree of functional sight. The retinal implant technology, developed and distributed by Second Sight, can improve quality of life for patients who have lost functional vision due to retinitis pigmentosa, a disease that causes retinal cells to die. But the implant doesn’t facilitate a sudden recovery of 20/20 vision.

Just as cochlear implants don’t have the sensitivity to accurately relay the complex mix of frequencies in music, bionic vision through the Argus II will be closer to a very grainy black-and-white film than an HD movie.

The multi-piece system starts with a digital camera mounted in eyeglasses. Images from the camera get translated into data through a miniature computer and sent via wireless transmitter to a computer chip on the side of the eyeball. From there, the chip activates an eyelash-thin electrode array implanted behind the retina, which then stimulates retinal cells to send visual information to the brain.

Bionic vision will be closer to a very grainy black-and-white film than an HD movie.

First Bionic Eye Second Sight

While the prosthesis sounds complex, it doesn’t compare to the intricacy of the natural human eye. Shawn Kelly, a scientist at Carnegie Mellon University, is currently working on his own retina implant system that includes the same basic technology as the Argus II. He explains that, with the technology available now, the electrode array isn’t finely tuned enough to produce the same detail and clarity of a fully functional human retina.

“It’s not going to be anything like normal vision,” Kelly says, describing the expected results of his implant. “It’s going to be very difficult to convey colors, and it’s going to be difficult to convey the type of visual resolution that we have in the center of our vision.”

The eye’s retinal cells, commonly known as rods and cones, are split up into six types of receptors that detect contrast between light and dark, red and green, and blue and yellow. Electrical signals from the retinal cells travel through the optic nerve to the brain to form a complete picture of what the eye is looking at.

Instead of trying to imitate the activity of all six receptor types, Second Sight’s Argus II implant focuses on stimulating retinal cells to show light and dark contrast. For a blind patient using an artificial retina, being able to detect the relative darkness of a hole or an approaching wall is a lot more important to independently navigating than knowing whether that wall is painted red or blue.

Brian Mech, vice president of business development at Second Sight, reports that in clinical trials, all of the company's 30 patients had some degree of vision improvement after receiving the retinal implant. “Basically they see black and white, shades of gray and they’re getting somewhere between 50 and 60 pixels of information on average,” Mech says.

In terms of acuity, the patient with the best result went from no useful sight to 20/1260 vision. This ratio means that to get the same amount of information a healthy human eye can discern from 1,260 feet, this patient would need to be standing 20 feet away.

Mech admits this level of acuity is limited. “[It] is still pretty poor considering normal vision is 20/20, but it’s pretty amazing when you’re completely blind to begin with,” he says. But he explains that as research and testing continues, there is plenty of room to improve the system’s performance just by working on the external technology. Even color vision is a possibility with improvements to the video processor and wireless transmitter. “I don’t want to make it sound too easy,” Mech says. “There’s a lot of work to be done before we can do color vision, but the good news is that they won’t need a new implant for it.”

Second Sight is currently developing more advanced retinal implants, but the timeline is still unclear. Mech says it will be five to seven years or more before the next generation of implants becomes a reality.

This story was produced in partnership with Northwestern University's Medill School of Journalism.

Do Women Have a Better Sense of Color?

We at SkyVision Centers, the premier ophthalmology practice in Westlake, Ohio would like you to weigh in on this!

Take the quiz and then post your color number and gender on the SkyVision Facebook Page!

What is your color sense- Your Color IQ