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Can we really restore vision for people with macular degeneration by using a silicon chip?

Teachable moment in classrooms:

  1. special senses chapter – layers or tunics of the eye
  2. special senses chapter – gross anatomical structures on the retina
  3. special senses chapter – microscopic layers of the retina

The news item:  Recently the following report appeared online:

Eye prosthesis is the first to restore sight lost to macular degeneration

In a Stanford Medicine-led clinical trial of a wireless retinal prosthesis, people with advanced macular degeneration regained enough vision to read books and subway signs.

 

The article states that the PRIMA device is able to restore functional sight to people suffering from age-related macular degeneration which destroys light receptors in the retina. The article also describes that the device has a wearable camera part, and an implanted chip, and that 27 out of 32  patients have achieved 20/42 visual acuity.

So, Why Do I Care??  According to the US Centers of Disease Control age-related macular degeneration affect in the US 20 million people who are older than 40. The disorder robs the patients of their central vision, so they see everything with a blurry patch in the middle of it. Reading, using a smart phone, reading road signs, recognizing people’s faces become cumbersome. So, this disease is making life difficult for large number of people, and new electronics-based solutions are always welcome to augment the pharmaceutical-based treatments.

Plain English, Please!!! First, let’s talk about how the retina allows us to see images. The retina is the light-sensing layer inside our eyeball. Imagine a balloon that is being covered up with grape jelly, and the grape jelly is covered with a dishcloth. In that metaphor the dishcloth is the fibrous tunic, such as the sclera of the eye; the grape jelly is the vascular tunic, and the innermost layer, the balloon is the nervous tunic or retina. The retina itself has three layers to it, the deepest photoreceptor layer, and two layers of neurons on top of that. The retina is mostly a smooth layer, but there is a bump the size of a black pepper in the middle of it. The bump is called macula lutea, and in it we find a huge number of cone and rod type photoreceptors. The image focused by the lens and the cornea are projected onto the bump, and huge number of photoreceptors stimulate the neurons in the bipolar and ganglion layers to create nerve impulses. Just under the photoreceptor layer is the retinal pigment epithelium layer where oxygen and nutrients are transferred into the retina and the waste products are removed from the retina.

Second, let’s talk about what is malfunctioning in macular degeneration. Because of the very large number of photoreceptors in the macula lutea, this bump is the most sensitive part of the retina, and most visual information streams to the brain from there. In macular degeneration small

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

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

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

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

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

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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