June 2016 is Fireworks Eye Safety Month

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Posted on 2nd June 2016 by Pacific ClearVision Institute in General |Retina

PCVI and many other eye health providers support the sound warnings regarding firework eye safety. With the Fourth of July only a matter of weeks away, it’s important to review reminders that can serve as a real protection.

According to the U.S. Consumer Product Safety Commission, fireworks are involved in thousands of injuries treated in U.S. hospital emergency rooms each year.

Most fireworks injuries occur during the one month period surrounding the Fourth of July.

- Fireworks devices were involved in an estimated 10,500 injuries treated in U.S. hospital emergency rooms in 2014 (the latest year for which data is available).
- An estimated 7,000 injuries were treated in hospital emergency rooms during the one-month period (June 20–July 20) surrounding the Fourth of July.
- 19 percent, or 1,200, of those injuries were to the eyes. Sparklers accounted for 1,400 injuries, firecrackers (1,400) and bottle rockets (100).
- Males accounted for 74% of fireworks injuries.
- 40% of fireworks injuries were to children under age 15.
- For children under 5 years old, sparklers accounted for the most estimated injuries for that specific age group.
- Data from the U.S. Eye Injury Registry shows that bystanders are more often injured by fireworks than operators themselves.
- Contusions, lacerations and foreign bodies were the most common injuries to eyes.
- There were 11 fireworks-related deaths in 2014.

Do Not Let Children Play With Fireworks

Fireworks and celebrations go together, especially during the Fourth of July, but there are precautions parents can take to prevent these injuries. The best defense against kids suffering severe eye injuries and burns is to not let kids play with any fireworks.

These Six Steps Can Help Save Your Child’s Sight

If an accident does occur, minimize the damage to the eye. In the event of an eye emergency:

- Do not rub the eye. Rubbing the eye may increase bleeding or make the injury worse.

- Do not attempt to rinse out the eye. This can be even more damaging than rubbing.

- Do not apply pressure to the eye itself. Holding or taping a foam cup or the bottom of a juice carton to the eye are just two tips. Protecting the eye from further contact with any item, including the child’s hand, is the goal.

- Do not stop for medicine! Over-the-counter pain relievers will not do much to relieve pain. Aspirin (should never be given to children) and ibuprofen can thin the blood, increasing bleeding. Take the child to the emergency room at once – this is more important than stopping for a pain reliever.

- Do not apply ointment. Ointment, which may not be sterile, makes the area around the eye slippery and harder for the doctor to examine.

- Do not let your child play with fireworks, even if his/her friends are setting them off. Sparklers burn at 1800 degrees Farenheit, and bottle rockets can stray off course or throw shrapnel when they explode.

If possible leave fireworks to the professional displays that are held at various venues on the Fourth of July.

(Thanks to PreventBlindness.Org)

Visual acuity

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Posted on 2nd June 2016 by Pacific ClearVision Institute in General |Retina

Visual acuity (VA) is acuteness or clearness of vision, especially form vision, which is dependent on the sharpness of the retinal focus within the eye, the sensitivity of the nervous elements, and the interpretative faculty of the brain.

VA is a quantitative measure of the ability to identify black symbols on a white background at a standardized distance as the size of the symbols is varied.

The VA represents the smallest size that can be reliably identified.

VA is the most common clinical measurement of visual function.

A visual acuity of 20/20 is frequently described as meaning that a person can see detail from 20 feet away the same as a person with normal eyesight would see from 20 feet.

If a person has a visual acuity of 20/40, he is said to see detail from 20 feet away the same as a person with normal eyesight would see it from 40 feet away.

It is possible to have vision superior to 20/20: the maximum acuity of the human eye without visual aids (such as binoculars) is generally thought to be around 20/10 (6/3).

Recent developments in optometry have resulted in corrective lenses conferring upon the wearer a vision of up to 20/10.

Some birds, such as hawks, are believed to have an acuity of around 20/2, which is much better than human eyesight.

Many humans have one eye that has superior visual acuity over the other.

If a person cannot achieve a visual acuity of 20/200 (6/60) or above in the better eye, even with the best possible glasses, then that person is considered legally blind in the United States.

A person with a visual field narrower than 20 degrees in diameter also meets the definition of legally blind.

Our brain suppresses perception related to heartbeat, for our own good

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Posted on 2nd June 2016 by Pacific ClearVision Institute in General |Retina

Our heart is constantly beating yet we normally do not feel it. It turns out that our brain is capable of filtering out the cardiac sensation so that it doesn’t interfere with the brain’s ability to perceive external sensations. For the first time, researchers from the Center for Neuroprosthetics at EPFL have identified this mechanism. They discovered that a certain region in the brain determines where internal and external sensations interact. Their work appears in the Journal of Neuroscience.

EPFL’s neuroscientists noted that the brain perceives visual stimuli less effectively if they occur in time with the heartbeat. It seems as if the brain wants to avoid processing information that is synchronized with the body’s heartbeat.

“We don’t see the same way as a video camera does”

“We are not objective, and we don’t see everything that hits our retina like a video camera does,” said Roy Salomon from the Laboratory of Cognitive Neuroscience, one of the study’s co-authors. “The brain itself decides which information to bring to awareness. But what’s surprising is that our heart also affects what we see!”

The researchers carried out an initial series of experiments with more than 150 volunteers. The volunteers were subjected to a visual stimulus — an octagonal shape flashing on a screen. When this geometric shape flashed in sync with the subject’s heartbeat, the subject had more difficulties perceiving it.

What’s happening in the brain — a first insight

The researchers just needed to figure out what was happening in the brain. They were able to show that a specific region, the insular cortex, acts as a filter and intercepts the sensations coming from the body’s beating heart.

They did this by running the experiment again in an MRI scanner. When the visual stimuli were not in sync with the subject’s heartbeat, the insular cortex functioned normally and the subject perceived the flashing octagon easily. But when the stimuli occurred in time with the heart rate, the level of activity in the insular cortex dropped noticeably: the subject was less aware — or totally unaware — of the flashing shape being shown.

It did not take long for Roy to get over his initial surprise at his discovery. “You don’t want your internal sensations to interfere with your external ones. It’s in your interest to be aware of what’s outside you. Since our heart was already beating while our brain was still forming, we’ve been exposed to it since the very start of our existence. So it’s not surprising that the brain acts to suppress it and make it less apparent.”

Is feeling one’s heartbeat related to anxiety?

Awareness of one’s heartbeat is known to be correlated with a number of psychological problems, including anxiety disorders. Patients typically perceive their heart rate more clearly than most people. “But someone who does not suffer from this type of disorder can also be aware of their heartbeat,” said Roy. “This can happen at times of intense excitement or fear, for example.”

Could anxiety disorders be, at least in part, the cause or effect of someone’s inability to silence their heartbeat? “We don’t know that yet. What we do know now is that, under most conditions, we are not aware of our own heartbeat and that there is a specific region of the brain whose task is to suppress it.”