Your Three Dimensional Cornea

When we ask you to stare into this machine during your next appointment at Allied Eye, you might wonder, "What kind of mind-control-hypno-conspiracy madness IS GOING ON HERE?!"

 Don't fret. We're not messing with magic. This vibrant bit of machinery plays a critical role in our understanding of your total eye health. It measures your CORNEAL TOPOGRAPHY. That's like an elevation map for your eyeball.

The cornea is responsible for a majority of the eye's refractive power, so it plays a major role in visual clarity and overall eye health. We use the 3D map produced to plan LASIK, cataract surgery, and to make sure your contact lenses fit well. 

With one eye at a time, you sit and gaze right into the center of this hypnotic-looking wheel, and the light from the purple rings reflects back into the machine. A computer builds an image for us based on the spacing between the rings, and viola! You've been mapped like a new-found mountain. 

Now.... When I snap my fingers, 

you'll have the strangest urge to tell your friends about Allied Eye!

*SNAP!*

The Cyclops (Halloween Special!)

Two is better than one. 

You might have not have noticed, but many living things, including humans, are typically sporting a PAIR of eyeballs. We have, as the experts call it, “binocular vision.”

 Luckily for us, Binocular Vision has advantages. For one thing, you've got an extra eye in case one gets damaged. You've also got a very wide field of view. One really significant benefit is depth perception.

Depth perception allows us to decode another creature's camouflage, or to detect an enemy hiding behind a distant column.

For those among us whose favorite color is “glitter,” you have binocular vision to thank for the effect of glitter’s transient scintillation, as one eye will see the tiny reflection of light while the other does not. You can examine this by focusing on a sparkle and closing one eye, then the other.

Playing with the "Cyclopean Image" 

The Cyclopean image is the single image constructed by the brain from two separate inputs.

To make a floating finger, put the tips of your fingers together. Focus on a point just above your hands, like something on the wall, while still paying attention to what your fingers look like. Slowly pull your hands apart, and ta-da! You’ve tricked your brain!

You can also try pointing at a door handle or corner. Close each eye, one at a time. Which eye commanded your action? Now your eyes are fooling YOU.

Last fun fact of the day:

It is commonly said that the legend of Cyclops came from the first discovery of these monstrous skulls:

As it turns out, that singular facial socket is actually the nasal opening in an elephant’s skull. That is, where the trunk goes. If you’d never seen an elephant on your part of the globe, would you have thought the same? 

Stop the Sweetness!

      Stop the Sweetness!

          Modern humans, especially those in the United States, have developed an astonishing taste for sugar. On average, we consume 500 calories from sugar daily, despite suggestions that sugar will damage our health. 

       With the playful, colorful packaging of candies and cans of soda, who can blame the average consumer for believing that sugars, in moderation, are perfectly fine?  The problem is that most people have no idea what a moderate amount of sugar is. 

According to the World Health Organization, it is vastly less than many people might assume. 

       When you look at the information label on the back of a 20 oz bottle of Coke, you’ll see the gram amount of sugar, but no indication of its percent daily value. This number is available for fat, sodium, and carbs, but not sugar. 

      In March of this year, the World Health Organization released its updated recommendation for our daily intake of added sugars. They suggest that we consume 6 teaspoons, or 24 grams, of sugar per day for ideal health. The maximum suggested amount is 12 teaspoons, or 48 grams. 

         Remember that 20 oz bottle of Coke you had for lunch? It contained 65 grams of sugar. Over 200% of the World Health Organization's suggested amount for the day. This raises an important question: If you saw that percentage on your beverage, would you drink it? 

         In August of this year, the FDA passed regulations that will require all food and beverage producers to include the sugar percentage on nutrition labels. 

        Many studies have shown that the excessive consumption of sugar is linked to a multitude of health problems. Sugar is said to silence the “fullness” hormone, leading to weight gain and obesity. It has been tied to memory loss, heart disease, and dental decay. Sugar in excess is understood to affect the liver in the same ways as alcohol abuse. Some studies have even suggested that sugar may play a role in breast and colon cancers. 

         Arguments about sugar and the sugar industry abound. Health officials are always at odds with industries that rely on heavy sugar consumption. Contested issues include the severity of health affects, risk of addiction, and controversial marketing strategies that target children. 

          There are even a number of accusations that sugar-dependent industries behave like the tobacco industry. It has been suggested that certain soft drink producers fund their own scientific research, and donate massive sums of money to community health programs in exchange for the adjustment of their mantras. "Health isn't about what you eat or drink. It's about how active you are." I heard this one in a recent Coca-Cola commercial.  
          
         Unlike the sugars present in fruits, which enter your system accompanied by fiber and vitamins, you need to watch out for those that are added at the time of processing. These include fructose, glucose, sucrose, cane sugars, syrups, and dextrose. These sugars have no nutritional value, but are added to make food more appealing. 


Huffington Post, 2013:
Ten Things You Don't Know About Sugar

American Journal of Physiology, 2009: 
Fructose Inhibits the "Fullness Hormone."

Nature Journal, 2012: 
Fructose Can Cause the Same Health Effects as Alcohol

Georgia State University: 
Sugar Impairs Memory in Rats

Newsweek, 2014: 
Sugar Lobbies Threaten Organizations, Bury Science

Center for Science and Democracy, 2014:
Industry Obscures Science, Undermines Public Health Policy on Sugar
       

How the Lens Came to Cataract Surgery

Many of us are familiar with the basic premise behind cataract surgery: when the lens inside of your eye gets cloudy, it's out with the old, and in with the new. Your surgeon breaks up the old lens, suctions it out, and implants a new, bright-and-shiny lens called an IOL, or Intraocular Lens.         

Both cataract surgery and lenses had LONG independent histories before they finally teamed up in 1950. It was then that they began their dual task of restoring and perfecting vision for millions of people around the world.

(This lens, the Loupe of Sargon, was fashioned in 750 BC in Assyrian Nimrud.)

Lenses begin to appear in the archaeological record as early as 750 BC, in ancient Greece, Egypt, and Babylon. These were made of polished quartz, and were used for starting fires and magnification. It is said that ancient Greeks used this technology to keep their "eternal Olympic flame" aglow by divine power.

Around the same time, cataract surgery began to appear in medical texts of India, and then of China. The procedure served only to push the cloudy lens material out of the eye, but there was nothing to replace it.

(Monet's "House Seen From the Rose Garden" after cataract surgery. Some people report that they can see ultraviolet light when the UV absorbing lens has been removed)

With no lens to replace the missing one, the eyes lose their focusing power and become very far-sighted. Obviously, this won't do if you're a painter, a surgeon, a shoemaker, or a bug collector.

(The first IOL, implanted in November 1949.)

It would be 1949 before lenses were finally modulated for use in the eye. The chosen material was deemed viable after ophthalmologists were able to observe eye injuries sustained by pilots of the Royal Air Force during World War II. Shattered pieces of Plexiglas resisted infection and remained inert inside the eyes of the wounded. Glass splinters of the same sort were rejected by the body.     

Further developments in design and technique had to come about before IOLs made their way into widespread practice. Today, tens of millions of IOLs are implanted worldwide every year.

 

 

Ophthalmic Science Fiction, Hold the Fiction.

A Brief History of the Retinal Scan 

     

     Thanks to innovations in ophthalmic technology, identification by retinal scan has evolved from a hypothetical possibility to a readily available, highly accurate tool. It still holds much sway in today's science fiction portrayals of advanced technology.

1886

Alphonse Bertillon's method was overtaken by fingerprinting, but the use of his "mugshot" remains. 1893.

     The concept of eye-recognition surfaced in 1886, when Alphonse Bertillon suggested that the eyes could be used to identify criminals. Granted, he imagined a system of identification based on the details in the iris, rather than the retina. Bertillon was a criminologist who recommended that the police record a long list of physical measurements in order to positively identify repeat offenders. Many of his practices were adopted for a time, but his only surviving technique is the photographing of individuals under arrest, known today as the mug shot.

1935

     The first scientifically supported idea for retinal identification was published in the New York State Journal of Medicine in 1935. The basic idea was to use the unique pattern of blood vessels in the retina to identify an individual. The technology for a device that could realistically perform this task would not emerge for decades. 

Popular Culture

        

Batman and Robin with the retinal-scan-equipped Bat Mobile
in the 1960s.

The relative obscurity and "high tech" nature of retinal scans means that they are a frequent device in fiction - to suggest that an area has been particularly strongly secured against intrusion, to indicate that technology has advanced beyond what we regularly see today, even to pronounce a dehumanization of technological advancement.

Captain Kirk debuts retinal scanning technology in 1982.

         Retinal scanners are mentioned for years before the first viable model was designed in 1975. Batman and Robin, for example,  use a retinal scanner in a 1966 film to identify the Penguin. In 1976, full time efforts were made to complete a

Congratulations, Jim. You are who you claim to be. 

scanning device, and in 1978 it was patented, with a commercial model following in 1981. Captain Kirk introduced the device in motion pictures in 1982. 

More instances of eye scanning in contemporary media.

How it Works

       Each person’s retina is unique because the structure of blood vessels is so complex. Not even identical twins share the same pattern. Though the patterns in the retina can be altered by certain eye

Image of the veins of a normal human retina. 

diseases, they typically stay about the same from birth until death.  Apart from DNA, retinal recognition is the most precise form of identification currently available, with an error rate of 1 in ten million.  

A retinal scan works by casting a beam of low-energy infrared light into a person’s eye as they look through the scanner's eyepiece. This beam of light traces a standardized path on the retina. Because retinal blood vessels absorb light more readily than the surrounding tissue, the amount of reflection varies during the scan. The pattern of variations is digitized and stored in a database. An algorithm has to be employed to analyze each image in a video stream that receives the information from a cast beam of light.

Applications

     Retinal scanners are typically used for authentication and identification purposes. They have been utilized by several government agencies including the FBI, CIA, and NASA. However, in recent years, retinal scanning has become more commercially popular. Retinal scanning has been used in prisons, for ATM identity verification and the prevention of welfare fraud.

          Retinal scanning also has medical applications. Communicable illnesses such as AIDS, syphilis, malaria, chicken pox and Lyme disease as well as hereditary diseases like leukemia, lymphoma, and sickle cell anemia affect the eyes., so scanning for retinal abnormalities can provide early awareness chronic illnesses.

       Very recently, smartphone apps like Peek use this technology in rural parts of the world where eye care is difficult to come by. Minimal training is required to operate Peek, as the information is gathered and then sent to experts around the world for diagnosis.

Impediments

       There are downsides to retinal scanning for the purposes of identification. Certain conditions like cataracts can impede light from entering the eye, thus obscuring retinal information. Accuracy can also be compromised by astigmatism. Scanning procedure is perceived by some as invasive, likely due to its presence in science-fiction stories where technology has gone a bit too far. The cost for reliable equipment also makes it too obscure for some potential users to employ practically. 

Drink Water for Eye Health

Drink Water for Eye Health

Water doesn’t get the media attention that privileges fad diets and miracle health supplements, but it plays a critical role in your health, particularly that of the eye. Dehydration is one of the main causes of dry eye. 

Warm weather can increase water loss by a factor of ten, so be diligent about drinking water to prevent and relieve your dry eye symptoms. Eye drops serve well as an immediate relief as you pound those fluids and wait for your body to thank you.  

 

 

WHAT IS DEHYDRATION?

Normal loss of water occurs all day long, through the lungs, skin, and kidney functions.  Dehydration happens when water leaves the body at a more rapid rate than it is consumed. When the body doesn’t have enough fluid, all organs, including the eyes, suffer.

A 3-4% water loss manifests as thirst and general discomfort. 

At 5-8%, expect fatigue and dizziness; grogginess, sleepiness, headache, nausea, tingling of limbs.

10 % yields physical and mental deterioration, severe thirst muscle spasms, skin will shrivel and wrinkle, vision dims, urination is reduced and becomes painful, delirium begins.

When your body faces a 15-25% water loss, conditions are often fatal. 

 



Tear composition

HOW DOES DEHYDRATION AFFECT THE EYES?

“Dry eye” is the loss of water content in the natural tear film, a thin layer of oil, water, proteins, and mucus.  When you are dehydrated, your eyes produce tears with a scanty amount of water, leading to dry eye, eye strain, and vision problems. Tear fluid water loss can weaken the eye’s resistance to bacterial and viral invasion. Tears are necessary for clear vision because they wash away foreign material from the eye. helping to reduce infections and injuries like corneal ulceration.

Without proper tear production, you may experience tired eyes, blurred vision, headache and double vision, due to the lack of lubrication while you blink and shift your gaze. These symptoms can also signify more serious conditions, so be sure to speak with an ophthalmologist about what you’re experiencing. 

AM I DEHYDRATED?

The best way to assess the state of your hydration is to reflect: have you consumed the recommended daily amount of water (12-15 cups), or are you well on your way? 

Various conditions increase water loss risks, so it is also critical to know your body. Here are some questions to ask yourself:

How’s my breath? 

Bad breath and dry mouth occur mutually, and signal dehydration.  Dehydration can prevent your mouth from producing enough saliva, so bacteria over-grow, releasing their special fragrances into your airstream. 

How’s my urine?

If you’re well-hydrated, your urine will be mostly clear with a tinge of yellow.  Yellow, chardonnay (a very flattering way to describe urine, I might add), and orange are “warning” colors. When your body is about three percent dehydrated, your urine will be noticeably yellow. When your body is about five percent dehydrated, your urine will appear chardonnay-colored. When your body is more than five percent dehydrated – which is considered severely dehydrated – your urine will appear orange.

How do my muscles feel?  

Muscles work hard in the heat, and will overheat and seize up. Changes in electrolytes, potassium, and sodium can cause cramping and seizing as well. 

How’s my head?

The brain sits inside a fluid sack that keeps it from bumping against the skull. If that fluid sack is depleted or running low because of dehydration, the brain can push up against parts of the skull, causing headaches. Lightheadedness, sleepiness, and unproductiveness also signal dehydration. 

Check your skin:

Dehydration causes a loss in blood volume, which leads to dry skin. You may also see flushing. To test your hydration level, use two fingers to grab a roll of skin on the back of your hand (between where your watch sits and where your fingers start).  Pull the skin up about ½ to one centimeter high and then let the skin go. The skin should spring back to its normal position in less than a couple of seconds. If the skin bounces back slowly, you might be dehydrated.

What am I craving?  

When you’re dehydrated, it can be difficult for organs like the liver to release glycogen and other components of your energy stores, because this is done with water. You can crave anything from chocolate to a salty snack, but cravings for sweets are more common because your body is experiencing difficulty with glycogen production. Salty cravings may be an attempt by your body to store water as a last attempt to address the emergency it thinks is happening.  A salt craving may last only as long as it takes to re-hydrate.

How are my eyes feeling? 

Dry Eye symptoms include an itching or burning irritation, blurred vision, and a feeling that foreign material is in the eye. These occur when the eye slows the production of tears, or decreases the amount of water in tears.

SPECIAL THREATS TO HYDRATION

Dehydration has risen to the level of a global health crisis in the past decade. Even if you have constant access to fresh drinking water, you may still be at an elevated risk for dehydration. Pay special attention to your circumstances:

How hot is it?

If you’re reading this right now, in mid-July, then the answer is yes, you’re at a much higher risk for dehydration. Warm weather and humidity can increase water loss by a factor of ten or more, and this water needs to be promptly replaced. 

Are you ill?  

Vomiting or diarrhea can cause severe dehydration. Worldwide, diarrhea is the second most common cause of deaths in children younger than five.

Are you a party animal? 

Excessive consumption of alcohol can dehydrate you very quickly. If you choose to raise your glass, meet this challenge to benefit your body: consume water in a ratio of AT LEAST 1 to 1.

Are you Diabetic? 

As the kidneys use water to remove excess glucose from the blood, an elevated amount of water is released from the body.

Are you traveling? 

Car, truck, and jetliner cabins can be extremely dehydrating, as the strictly recycled air is often low in humidity. The same effect can happen if you are often in an insulated, air conditioned environment. If your rooms are too dry, put out plants or a plate of water to evaporate into the air.

Are you older than 50? 

After the age of 50, it becomes harder to read your body’s cries for water. You may not feel thirsty as vividly, and therefore may forget to drink the required daily amount of water. Many senior citizens suffer from dehydration.

SPICE UP YOUR RELATIONSHIP WITH WATER:

Unfortunately, it can be difficult to remember to treat our bodies well, or to convince ourselves to choose a simple glass of water over a bubbly, sugary soda. Here are some tips and habits to adopt  that will make water your best friend (and soul mate).

 

Keep a water bottle handy: 

If it’s right next to you, you’re more likely to drink it. It’s as simple as that. 

Try flavoring your water: 

Try adding fresh mint, slices of cucumber, lime, or even ginger to your water. Also, try naturally flavored calorie-free seltzers (La Croix is my favorite) .Their fizz and fruit flavor makes them more appealing than plain, flat water

Try Tea: 

Reach for unsweetened tea bags, which are available in lots of different flavors. Sip fruity iced teas during the day, or cozy up with a mug of hot peppermint or chamomile tea at night — they all count towards your daily fluid goal. 

Fruit the good Fight: 

Fruits are an excellent source of water, particularly watermelon, which is made of up to 90% water. Oranges and grapefruit also play a helpful role in hydrating your body. Veggies like celery, cucumbers, tomatoes, green peppers, and romaine lettuce are very hydrating.

 

Sip more during meals: 

This will help you eat more slowly, pace your eating, and stay hydrated. 

Opt for room temperature water. 

When it comes to fluids, steer clear of extreme temperatures. When ice water comes into the stomach it constricts the arteries surrounding the stomach, prohibiting the uptake of fluids until the water reaches a more usable temperature.

Easing Your Ride into the Sunset

Picture this:

A grand adventure… Overflowing with danger and romance, culminating in a triumphant ride into the sunset; a haggard and lonesome hero, returning home or on to Glory….

Luckily for us, we regular folks get to ride into the sunset far more frequently than the heroes of those stories. The only hang-up is that it’s not nearly as romantic as we might wish it was. When you’re on your way to or from work, the sun can paint either a dazzling display on the clouds, or a dangerous span of unbearably bright light, endangering ourselves and those around us.

Follow these helpful suggestions to ease the inconvenience of driving directly into the blinding sun:

Slow down to reflect the fact that your vision is compromised. Use extra caution, especially during school zones. Expect the rest of traffic to slow down, and keep an eye on your rear-view mirror for traffic that may be rapidly approaching from behind.

Invest in polarized sunglasses. They will help reduce glare. Have them within reach and ready for your face.

Use your drop-down visor to block out the sun, but be sure to keep an eye on traffic lights.

Leave more following room between your car and the car in front of you.

Drive with your headlights on to increase your visibility to other drivers. Having headlights on will also set your tail lights at full luminosity, which will benefit drivers behind you who are also struggling to see.

Keep your windshield clean, inside and out. Use either glass cleaner or a vinegar/water mixture to wipe down glass, even if it looks clean. Some dirt will only cause problems when the sun is at its lowest visible point.

Avoid storing papers on your dash board, as the reflection on your windshield can obscure vision.

Use lane markings to help guide you. Look toward the edge of the road, and not directly at the sun. Looking directly at the sun can damage your retinas. Stay focused on driving.

If you need to, pull over. Do this SAFELY, OUT OF THE WAY OF TRAFFIC. It often only takes a few minutes for the sun to reach a tolerable angle. If you don’t trust yourself or other drivers, it will be worth the wait.

Allow time in your routine so that you do not have to rush. If possible, adjust route timing to avoid times when sun glare is most extreme.

Reflection, Refraction, Burning Cars, and Survival Skills

We’re having one SIZZLING summer over here at Allied Eye!

In the spirit of this heat wave, we’re turning lemons into lemonade by highlighting the unique learning experience we had at the office yesterday!  

Yes. This is in our staff parking lot.

Let us tell you… We were handed some very big, very juicy lemons.  Here’s what we suspect happened:

Dr. Matzkin had a concave mirror sitting in the back seat of his car – like the curved mirrors used for applying makeup. Sunlight streaming through the window reflected off the mirror, formed a concentrated hot spot, and ignited the interior of his car. Think of the way you can use a magnifying glass to set leaves ablaze.

Example of a convex mirror focusing the sun's rays onto a smoldering object.

How, you may ask, is this an interesting example of eye-related processes?  The irony here is that Dr. Matzkin basically employs this principle every day when making refractive corrections to our patients’ vision.

In fact, the WAY YOU SEE is a result of this phenomenon: light bends when it enters your eye and focuses itself on your retina. By changing the shape of your lens (cataract surgery, contacts, glasses, LASIK are all examples), that beam of light becomes MORE focused, and it produces a clearer image when it reaches the back of your eye. 

Convex REFRACTION (Lens of the Eye)

The way light bends and curves when it passes through a substance is called refraction. When it bounces off a surface, that’s reflection. With a more perfect lens comes a more perfect focal point, and with that comes more perfect vision.  

Concave REFLECTION (Mirror and Flaming car)

For our purposes, we will call these tools “burning mirrors” and “burning lenses” when they are used to create fires.

The earliest lens artifact, discovered from the 7th century BCE in ancient Assyria may have been used as a burning lens. The earliest record of “burning mirrors” comes to us from the Greek mathematician, Diocles, in the 3rd Century BCE (Consider that the lens was not modified for use in cataract surgery until the 1950s).

Burning lenses have been used historically to cauterize wounds and to light sacred fires in temples (the eternal Olympic Flame, for example). During the French Revolution, the French government considered developing the burning lens into a weapon that would ignite British Ships from afar. In the 18th century, burning lenses became popular for use in chemical experiments. 

Not All burning glass ideas are brilliant, as you may have assumed by the first photo in this entry… In a 1920’s book by William Bates, the author argues that vision can be perfected by "Focusing the Rays of the Sun Upon the Eye of a Patient by Means of a Burning Glass.” Needless to say, this is highly dangerous and will damage the eye in seconds.

Today, burning lenses and mirrors have plenty of practical applications, like headlights, lighthouses, and solar stoves.