TEACHABLE MEDICAL NEWS

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Tag: vision

Can we really replace an damaged iris with a silicone one in the human eye?

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On September 28, 2025

In special senses, tissues

Teachable moment in classrooms:

  1. tissue chapter – characteristics and locations of smooth muscle
  2. special senses chapter – structures inside the eyeball
  3. special senses chapter – location of the iris and the action of smooth muscle to change pupil diameter

The news item: Recently, the following report appeared online:

Independence woman regains sight after first-of-its-kind surgery in Missouri

In 2010, Jennifer Sanders suffered an orbital globe rupture which destroyed 95% of the iris in her right eye.

The article states that a woman whose eye ruptured in an accident suffered from poor vision and light sensitivity because of a destroyed iris. An artificial iris implanted into her eye resulted in much improved vision.

So, Why Do I Care??  In addition to trauma-caused damage of the iris, about 1% of cataract surgeries damage the iris, and there is a developmental disorder called aniridia that results in the underdevelopment of the iris. Thus, there are tens of thousands of people who suffer from the absence or malfunctioning of the iris. Poor vision affects the ability to learn in school, to get a job, to drive a car, among other things, so it is important to seek out solutions for these conditions.

Plain English, Please!!!  First, let’s talk about the location and function of the iris. The iris is a flat, thin ring inside the eye. For the shape just think about a donut that somebody sat on. The forward-looking surface of the “flattened donut” is the visible, colored part of the iris; this gives us the color of the eye. The backward-looking surface of the iris is made up of a thin layer of smooth muscle. The circle-shaped opening in the “flattened donut” is the pupil where light passes through towards the deeper portion of the eye. Because of the action of the smooth muscle, the pupil can be made wider or narrower. A narrow pupil prevents large amount of light entering the eye as that light would overload the photoreceptors in the retina. A wide pupil allows more light into the eye in a dim environment, so the photoreceptors can receive enough light for producing visual experience.

Second, let’s talk about the implant itself. The implant is made of silicone, and shaped like the biological iris. It is placed into its normal location, immediately in front of the lens.  Because silicone doesn’t

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Can we really carry out vision tests with AR goggles and artificial intelligence app?

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On July 17, 2023

In nervous system, special senses

Teachable moment in classrooms:

  1. special senses chapter – location of retina, the third tunic of the eye
  2. special senses chapter – location and importance of macula lutea
  3. special senses chapter – the retina needs blood supply to bring oxygen and nutrients to the neurons of the retina
  4. special senses chapter – location of liquid-filled spaces inside the eye
  5. special senses chapter – the sensory cells called rods and cones of the retina detect light

The news item:  Recently the following news report appeared online:

 

Duncansville Eye Practice Using AR-Type Headset to Diagnose Major Eye Issues

A Duncansville eye practice is using a new augmented-reality device made by Florida-based company Heru to diagnose severe conditions in patients. This AR-like headset can detect serious eye diseases like Glaucoma in minutesand it’s being used right here in Blair County.

The report states that the HERU is a headset with goggles, and the equipment projects flashes of light in the visual field of the eye, and asks the test subject to respond when they see the light. Among other conditions, glaucoma can be diagnosed with the device.

So, Why Do I Care??  Deterioration of vision is a major threat to quality of life in an aging population. The most serious causes of vision loss are glaucoma and age-related macular degeneration, affect over 13 million people in the US. Faster and easier to perform diagnostic process can ensure that people can get an early diagnosis, and more effective treatment. In addition to those two eye disorders the HERU device can diagnose 7 additional eye disorders, indicating the versatility of the device.

Plain English, Please!!!  First, let’s talk about what glaucoma is. This eye disorder develops because of the increased pressure inside the eye. The pressure is coming from the accumulation of aqueous humor in the front (anterior) cavity inside the eye. The increased pressure is then transferred to the vitreous humor of the posterior cavity.  The vitreous humor compresses the blood vessels on the surface of the retina, and that slows the flow of oxygen and nutrients to the light-sensing cells (rods and cones). Picture a garden hose with water flowing through it. If someone steps on the hose the water flow slows down. The same happens to blood vessels of the retina if they are compressed. Without enough oxygen and nutrients the rods and cones start dying, and they no longer detect light, and that leads to vision loss.

Second, let’s talk about what age-related macular degeneration is. This eye disorder develops when a small patch of the retina, the macula lutea, malfunctions. The cause of macular degeneration is

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Can we really put an implant inside the eye to deliver drugs to treat eye diseases?

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On June 15, 2022

In cellular basis of life, special senses

TeachableMedicalNews article 06152022

Teachable moment in classrooms:

  1. cellular basis of life chapter – diffusion as a means of molecular movement
  2. special senses chapter – the photoreceptors rods and cones are in the retina
  3. special senses chapter – liquid-filled chambers of the eye
  4. special senses chapter – sclera, the white of the eye, is the toughest, outer layer

Can we put an implant inside the eye to deliver drugs to treat eye diseases?

The news item:  Recently a report appeared about a drug, Susvimo, that reverses blindness:

New technology helps Georgetown veteran restore his eyesight

If you’re living with blurry vision, there’s a chance a new device can help you get your eyesight back without frequent visits to the doctor. The newly FDA-approved Susvimo implant helped one Georgetown veteran preserve his vision after being diagnosed with wet age-related macular degeneration.

The article states that AMD (wet, age-related macular degeneration) is the leading cause of blindness over the age 60, that this disorder is caused by growth and scarring of blood vessels under the retina, and that drug-delivery through an implant has restored vision in 90% of the treated individuals.

So, Why Do I Care??  Eye diseases can rob people of their vision. Many of such diseases are treated by injection of a drug into the eye. It is estimated that there are over 10 million such injections per year in the USA. Because chronic eye disorders require several injections into the same eye, it is worth exploring alternative delivery systems for long-term administration of drugs.

Plain English, Please!!!   First, let’s review the action of Susvimo, the drug we will use as an example to learn about implants inside the eye. In a previous post of Teachable Medical News (TMN 05252022), we described the action of the drug Susvimo. Here is a brief summary:  Normally the light-sensing cell in the

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How does drug injection into the eye save people from blindness?

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On May 24, 2022

In cardiovascular system, nervous system, special senses

TeachableMedicalNews article 05252022

Teachable moment in classrooms:

  1. special senses chapter – location of macula lutea in the retina of the eye
  2. special senses chapter – the photoreceptors rods and cones are in the retina
  3. hemodynamics chapter – capillaries are the thinnest blood vessels
  4. hemodynamics chapter – endothelial cell location in capillaries

The news item:  Recently a report appeared about a drug that restores eyesight:

New technology helps Georgetown veteran restore his eyesight

If you’re living with blurry vision, there’s a chance a new device can help you get your eyesight back without frequent visits to the doctor. The newly FDA-approved Susvimo implant helped one Georgetown veteran preserve his vision after being diagnosed with wet age-related macular degeneration.

The article states that AMD (wet, age-related macular degeneration) is the leading cause of blindness over the age 60, that this disorder is caused by growth and scarring of blood vessels under the retina, and that the drug-delivery implant has restored vision in 90% of the treated individuals.

So, Why Do I Care??  Blindness is a condition where a significant part of the eyesight is lost, and such loss has a severe negative impact on people’s lives. In the USA alone there are about a million patients with wet age-related macular degeneration, and without treatment most of them will go blind.

Plain English, Please!!!   First, let’s talk about how the structure called macula plays a role in our vision. When we say we see something, the image of that something has to be turned into a nerve impulse so

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What makes some hand sanitizers dangerously toxic?

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On August 28, 2020

In cellular basis of life, chemical basis of life, digestive system, metabolism, nervous system, Uncategorized

TeachableMedicalNews article 08282020

Teachable moment in classrooms:

  1. chemical basis of life chapter – adenosine triphosphate (ATP)
  2. cellular basis of life chapter –sites of detoxification inside the cell
  3. cellular basis of life chapter – mitochondria as site of ATP production
  4. digestive system chapter – absorption through stomach mucosa
  5. metabolism chapter – electron transport chain as most efficient ATP producing process inside mitochondria
  6. special senses chapter – gross anatomy of optic nerve

The news item:  A recent news item described over a hundred hand sanitizer brands are being removed from store shelves because they may be dangerously toxic:

FDA says to avoid these 130 hand sanitizer products that may not work, or are toxic

Regulators say some of the products contain dangerous levels of methanol, which can lead to blindness, hospitalization and even death.

The article mentions that the toxic ingredient is methanol, and that it may cause blindness.

So, Why Do I Care??  Poisoning by methanol, also called wood alcohol, sickens over 20,000 people each year in the US.  These people may become blind in 24 hours, and suffer long-lasting damage to their kidneys and brain. The best prevention is not to consume methanol either by drinking or through contact with skin, such as through hand sanitizers.  So, taking hand sanitizers off the shelf is part of the prevention.

Plain English, Please!!! First, let’s talk about what methanol is. Methanol is chemically similar to ethanol, the alcohol in adult beverages. Methanol gets into hand sanitizers when the ethanol ingredient is contaminated with methanol. When ethanol is made by distilleries, sometimes inadvertently methanol is distilled into the product, so then it becomes part of the hand sanitizer.

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