Lesson Plan #4
Corneal Transplants
Objective: Following this lesson, students will have an understanding of corneal transplants. Students will be able to comprehend the complexity of corneal transplant surgery, as well as what it might be like living with a cornea disease that would require a transplant. They will also complete an activity that allows them to decide who would get a cornea transplant in various scenarios.
Time: 15 minutes
Materials Needed
• Print out Corneal Transplant Matching Worksheet
• Print out Corneal Transplant Matching Answer Sheet
• Corneal blindness glasses, request the glasses by emailing LifeShare Marketing
Lesson Plan
• Review reading materials about corneal transplants.
• Have students put on corneal blindness glasses and try to complete every day tasks, (e.g. writing, reading, looking at a person and having a conversation). This would be best done if set up in stations.
• Complete Corneal Transplant Matching Worksheet. Discuss reasons for choosing each as a class after the worksheet is complete.
Time: 15 minutes
Materials Needed
• Print out Corneal Transplant Matching Worksheet
• Print out Corneal Transplant Matching Answer Sheet
• Corneal blindness glasses, request the glasses by emailing LifeShare Marketing
Lesson Plan
• Review reading materials about corneal transplants.
• Have students put on corneal blindness glasses and try to complete every day tasks, (e.g. writing, reading, looking at a person and having a conversation). This would be best done if set up in stations.
• Complete Corneal Transplant Matching Worksheet. Discuss reasons for choosing each as a class after the worksheet is complete.
The corneal blindness simulation glasses were provided by the Oklahoma Lions Eye Bank.
CORNEAL TRANSPLANTS
Any number of events, from a corneal disease to irreparable damage from trauma, could generate the need for a corneal transplant. During a transplant, the surgeon delicately removes the damaged or diseased cornea from the patient’s eye using surgical instruments. The surgeon replaces the old cornea with the donated cornea, which is prepared to fit perfectly into the patient’s eye.
The surgeon uses very fine stitches to secure the new cornea into the patient’s eye and the stitches are left there until the cornea has bonded completely to the eye. The surgeon can also periodically adjust the stitches to help shape the cornea to allow the patient to see better through it. These stiches are 28 microns (ųm) thick!
(Images courtesy of Transplantation Science Book and Donor Alliance)
(Images courtesy of Transplantation Science Book and Donor Alliance)
What is a micron?
One micron is one-millionth of a meter! That’s 1/1,000th of a millimeter. A micron is symbolized by the notation: ųm. The stitches used in cornea transplant surgery are 28 ųm thick and the needle is 70 ųm thick.
To get an idea of how big a micron is, consider these things:
A dime is about 1 millimeter thick, or 1,000 ųm.
A dime is about 1 millimeter thick, or 1,000 ųm.
This is a cross-section scan of a human cornea. It is 559 ųm thick or about half the thickness of a dime.
This is an electron microscope scan of a human hair. The average human hair is about 190 ųm thick. If you stacked up six human hairs, they would be about equal to the thickness of a dime.
(Images courtesy of Transplantation Science Book and Donor Alliance)
Corneal Slit Lamp Evaluation
After donated corneas are recovered and brought to the eye bank, they are first evaluated under the slit lamp. With this instrument, eye bank technicians look at all five layers of the cornea. If there are no signs of physical damage to any cell layers, the cornea will go on to the next phase in the evaluation process.
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Figure 1 is an example of what a healthy cornea looks like under the slit lamp. The outer layer, or epithelium, appears intact and translucent. There are no signs of physical damage or deterioration of the epithelium or the other four layers.
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Figure 2 is a cornea that shows significant dryness and deterioration of the epithelium. This cornea is more opaque and doesn’t allow much light through. Unfortunately, it does not appear to be healthy enough for transplant.
(Images courtesy of Transplantation Science book and Donor Alliance) |
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Put on corneal blindness simulation glasses and try to do the tasks as instructed by your teacher. Decide if you would want a transplant if this was your vision quality.
Request the glasses by emailing LifeShare Marketing, the corneal blindness simulation glasses were provided by the Oklahoma Lions Eye Bank.
Request the glasses by emailing LifeShare Marketing, the corneal blindness simulation glasses were provided by the Oklahoma Lions Eye Bank.
Use the Corneal Transplant Matching Worksheet and Corneal Transplant Matching Answers now.