TEACHABLE MEDICAL NEWS

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Tag: high school

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 an injectable treatment work for migraines?

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On July 31, 2019

In lymphatic and immune system, nervous system

TeachableMedicalNews article 07312019

Teachable moment in classrooms:

  1. general senses chapter – unconventional types of pain
  2. general senses chapter – pharmaceuticals in of pain control
  3. immune system chapter – antibodies as pharmaceuticals

 

Can an injectable treatment work for migraines?

 The news item:  New injectable preventions and treatments for migraine were in the news recently. One of them is Aimovig (erenumab):

FDA approves new drug that stops chronic migraines

The FDA approves, Erenumab, a new migraine treatment, that blocks chronic and disabling headaches, without causing many side effects.

The article mentions migraine statistics, the calcitonin gene related peptide (CGRP) as the culprit in migraines, and that the new drug is an antibody.

 

So, Why Do I Care??  There are about 39 million migraine sufferers in the USA.  Among them about 4 million who suffers from chronic migraine lasting for 10-14 days.  The impact of migraine is more than the personal suffering; the US economy loses $36 billion yearly because of lost productivity linked to migraine.  While occasional migraine can be successfully treated with common medications, the chronic migraine sufferers don’t have a reliable treatment.

 

Plain English, Please!!!  First, let’s talk about migraine.  Migraine is a disorder of the central nervous system, and during a migraine attack the malfunctioning nervous system creates pain in the head area, visual disturbances (auras), and sometimes dizziness and nausea.   So, that’s why this disorder is so debilitating.

Second, let’s talk about pain, this warning signal of our nervous system.  We sense pain when tissue damage triggers nerve impulses in the nerve cells of the damaged body area, and those neurons conduct the nerve impulse to the brain.  Everyday pain killer drugs either block the action of chemical released during tissue damage, or they block the movement of the nerve impulse to the brain.

Third, let’s talk about this new treatment for migraine. Because migraine is not the result of tissue damage, common pain killers don’t work on chronic migraine pain.  Many years of research identified a chemical that trigger migraine pain; that chemical is called calcitonin gene related peptide (CGRP).  Migraine happens when CGRP reaches receptors on the neurons in the brain.   The receptor is like a wide receiver in football; the peptide has to be caught by the receptor to start migraine pain, like the wide receiver has to catch the football for a touchdown.  So, how can you block the action of that migraine-triggering peptide?  Imagine a football game where the arms of the wide receiver are duct taped to his body.  The drug erenumab does that to the receptor, so the CGRP peptide can not be caught by the receptor, so there is no more triggering of pain.  The duct tape, erenumab, can target CGRP receptors only, because erenumab is a modified antibody, a protein made by immune system cells to specifically target invaders in the body. As antibodies are proteins, they can not be taken orally, but have to be injected.

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