bionic Eye Lesson Plan - EDGE

TEAK – Bioengineering Artificial Eye Lesson Plan

TEAK Traveling Engineering Activity Kits

Biomedical Engineering Kit: The Artificial Sensory Systems The Artificial Eye Activity


Instructor Preparation Guide: Artificial Eye Activity

Bioengineering Overview

Bioengineering is the application of science, mathematics and engineering principles to

define and provide solutions to problems in the fields of biology and medicine. An example of a

product created by bioengineers is the artificial eye.

Human Sight Overview

The human eye is a complex organ. Its function can be broken down into three stages.

• The first stage is the collection of light. At the front of the eye, a lens like component

adjusts the visual focal point by stretching or contracting the lens. This allows an

individual to focus on objects that are either far or close to the individual.

• The second stage is the processing of visual light. At the back of the eye, there are two

types of receptors called cones and rods. Cones help the individual to detect and

distinguish different colors. The human eye has red, green and blue cones. Rods help the

individual to detect and distinguish between light and dark.

• The third stage is the process of stimulating the brain. After a receptor is stimulated, an

electrical pulse is sent out thru the optic nerve to the visual cortex of the brain. This is

the area of the human brain where visual stimulants are processed.

Figure 1.0 - The Human Eye


Simplified Definitions:

Cones – Receptors in the eye that are stimulated by colors

Rods – Receptors in the eye that are stimulated by different intensity of light

Optic nerve – a sensory nerve that allows the receptors in the eye to send electrical pulses to the

brain

Visual Cortex – The area of the brain that processes vision. This is located in the back region of

the brain. If you fall on the back of the head and you see stars, it is because the

visual cortex of the brain was stimulated by the shock of falling.

Engineering of Sight Overview

Individuals with visual problems could have damaged or defective lenses, receptors, or even

optic nerves. Engineers and scientist have been studying how the human eye works and

functions in hopes to find solutions for the visual impaired. Currently, bioengineers are working

to develop a device called the artificial eye. The artificial eye is a device that can replace the

second and last stages of the eye to allow the individual to process and stimulate the brain.

Figure 2 – Artificial Eye Implants


Stages of an Artificial Eye

• The first stage is the collection of light. If an individual has a problem with their lens,

they suffer from nearsightedness or farsightedness.

- Nearsightedness – A condition in which an individual has difficulties viewing

objects from a distance.

- Farsightedness – A condition in which an individual has difficulties viewing

objects from a close distance.

Solutions to these problems include obtaining glasses, or contact lenses, or even laser

vision surgery

- To learn more about types of visual impairments, visit the following link:

http://www.everydayhealth.com/vision-center/the-eye-exam/nearsighted-

farsighted.aspx

• The second stage is the processing of visual light. Engineers have thought of two ways to

replace human receptors

- Camera – Engineers can attach a micro camera to a pair of glasses to easily allow

an individual obtain vision. This attachment however is noticeable to others and

requires transferring of large signals into the visual cortex. Thus large bulky

wiring is required to be sent from the glasses, thru the human skull and into the

brain.

- Electrodes – Engineers have also devised a plan to implant electrodes into the

human eye. These implants will contain millions of electrodes to stimulate

different locations of human sight. However this technology is not fully

developed.

• The third stage is the process of stimulating the brain. Stimulating the brain with

electrical pulses is not a problem for engineers. The main problem for engineers is

finding the right location of the brain to stimulate for images to appear accurately.

- To learn more about modern prototypes of the artificial eye, visit the following

link:

http://www.youtube.com/watch?v=GZ0G9odShF4


Keynotes to the Artificial Eye Kit

• The following kit is designed to operate with infrared light signals. Infrared light signals

are safe and can also be found in all TV remote. These signals are not visible to the

human eye.

• The following kit operates with an operation amplifier. This allows small readings to be

amplified. In this circuit, the larger the resistance used, the larger the gain.

• To increase the distance of operation, the larger resistance is desired due to larger gain.

• Raising the resistance too high, having no resistor at all, will thus give an infinite gain

and will make the output light never turn off. (The artificial eye won’t stop stimulating

the brain)

• To simplify the circuit to allow the 6th

graders to build, the circuit does not operate at far

distances. This kit should operate from within a foot.

• The 6th

graders are to find the optimal resistance to operate at far distances and be able to

turn off.

Resources

• http://www.everydayhealth.com/vision-center/the-eye-exam/nearsighted-farsighted.aspx

• http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html

• http://www.youtube.com/watch?v=GZ0G9odShF4

Image Resources

• Figure 1: http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-

org/chap16/F16-01%20Human%20eye.jpg

Date: Feb 04, 2009

Time: 6:30 pm

• Figure 2: http://www.cyberpunkreview.com/news/Artificial-eyechip3.jpg

Date: Feb 04, 2009

Time: 6:40 pm


Activity Preparation Guide – Artificial Eye Activity

Overview

The Artificial eye kit contains activities for students to gain a better understanding of how

the human eye operates. Applying the same science concepts into engineering, a Artificial eye

model can be demonstrated to these students. The main focus of this kit is to teach students

about the human eye and the possibilities for engineers to create or modify the human eye to help

those with vision problems.

Learning Objectives

By the end of this lesson, students should be able to…

• Explain that the eye is a receptor for human vision.

• Explain that the eye sends visual images to the brain in the form of electrical pulses.

• Recognize that engineers can simulate biological ideals with electrical circuitry to create

devices such as the artificial eye.

• Associate the parts of the artificial eye system to corresponding parts of the human eye

system.

Engineering Connection

Engineers can apply the same science concepts of how the human eye operates to design

functional artificial eyes. Artificial eyes function exactly like the human eye in ways such as

receiving signals and processing them as electrical signals to the brain. To demonstrate how

these signals are received and processed by the brain, infrared LEDs will be used. Students

performing this activity will experience the same fundamental problems and limitations current

engineer are having while designing a realistic artificial eye. Examples of such limitations are

creating receptors sensitive towards different intensities of lights, where and how to stimulate the

brain accurately to match where the light is being viewed by the individual.


Activity Descriptions

A.) Teaching about the importance of vision: 10 Minutes

- Students will be asked to give examples of why they think the human eye is

important. How it helps them become aware of their surroundings, play video

games, watch television and etc.

- They will then be asked of how they think it would feel to be blind and give

examples of the difficulties blind individuals would have to face.

- Students will be given a physical model of the human eye as a visual aid. They

will be briefly informed of how the eye contains many receptors (cones and rods)

of light signals and that the eye processes these light signals into electrical pulse

for the brain.

- Introduce the design concept of the Artificial eye relating to how the human eye

functions in a similar way.

B.) Constructing a model Artificial eye: 20 Minutes

- An Infrared Artificial Eye model will be presented to the students.

- Students will be given infrared LED flashlights. These will be used for

representation of light signals that are picked up by the human eye. Students

should be given the chance to operate the infrared LED flashlights with the

Infrared Artificial Eye model. The students can watch a red LED light,

representing the brain, light up.

- Electrical components will be given out to the students so that they may construct

the artificial eye circuitry on a breadboard. In addition, two laminated sheets will

be given out to identify and explain the electrical and biological equivalent

components of the artificial eye circuitry.

- With the supplied infrared LED flashlights, students can experiment with their

own constructed circuit board.

- To think like an engineer, students must think of a way to optimize the artificial

eye circuitry. Students will be given different resistors to test. For each resistor

tested, the maximum distance of operation of the infrared LED flashlight to the

artificial eye circuit board will be collected and recorded onto a handout. This

will allow the students to get an engineering perspective of designing and testing

a circuit.

- Students must find the resistor value that would operate the furthest from the

infrared LED flashlight and turn off when the infrared LED flashlight is not on.


C.) Matching handout: 5 Minutes

- Students will be given a handout where they can match the human eye with the

components of the artificial eye.

D.) Group Discussion: 10 Minutes

- The concluding group discussion would be to go over the handout sheet, discuss

how studying the human eye has allowed engineers to design other devices such

as web cams and cameras, the problems current engineers are facing about

constructing an artificial eye, and answer any other questions the students might

have.

New York State Learning Standards

New York State Technology Learning Standards

a. Standard 1: Engineering Design

o Engineering design is a repetitive process involving modeling, optimization, and finding the best solution within the given constraints that is used to develop technological and innovative solutions to technical problems.

o Students:

• Activate devices.

• Recognize why an object or choice is not working properly.

• Recognize how a defective simple object or device might be fixed.

• Under supervision, manipulate components of a simple, malfunctioning

device to improve its performance.

• Design a structure or environment.

a.) Standard 5: Management of Technology

- Project management is essential to ensuring that technological endeavors are profitable and that products and systems are of high quality and built safely, on schedule and within budget.


New York State Science Learning Standards

a.) Intermediate Standard 1: Analysis, Inquiry, and Design.

- T1.1: Identify needs and opportunities for technical solutions to from an

investigation of situations of general or social interest.

- T1.1a: Identify a scientific or human need that is subject to a

technological solution which applies scientific principles.

- T1.3: Consider constraints and generate several ideas for alternative solutions, using

group and individual ideation techniques (group discussion, brainstorming, forced connections, role play); defer judgment until a number of ideas have been generated; evaluate (critique) ideas; and explain why the chosen solution is optimal.

o T1.3a: Identify alternative solutions base on the constraints of the

design.

- T1.4: Develop plans, including drawings with measurements and details of

construction, and construct a model of the solution, exhibiting a degree of

craftsmanship.

o T1.4a design and construct a model of the product or process

o T1.4b construct a model of the product or process

- T1.5: In a group setting, test their solution against design specifications, present

and evaluate results, describe how the solution might have been modified for

different or better results, and discuss trade-offs that might have to be made.

o T1.5a test a design

o T1.5b evaluate a design

* Note: Many of these resources were used in assisting the creation of the following Lesson

Plan and we want to thank and reference them for their valuable instruction.


The Artificial Eye Activity

Figure 3.0 – Artificial Eye Implant

DURATION

45-50 Minutes

CONCEPTS

Bioengineering

Human Sight System

Engineering Sight

Artificial Eye Activity


Bioengineering Discussion: (2 Minutes)

Background Information:

Bioengineering is the application of science, mathematics and engineering principles to

define and provide solutions to problems in the fields of biology and medicine. An example of a

product created by bioengineers is the artificial eye.

Group Discussion: Bioengineering Background

(Pose the following questions to the group and let the discussion flow naturally… try to give positive feedback to each child that contributes to the conversation)

What do you think bio (biology) means?

• The study of life and a branch of the natural sciences that studies living organisms and

how they interact with each other and their environment.

• The study of the environment.

• The study of living organisms and living systems.

What do you think engineering is? What do you think it means to be an engineer?

• A technical profession that applies skills in:

o Math

o Science

o Technology

o Materials

o Structures

Discuss with the students what bioengineering is and the broad scope of areas that

bioengineering includes. For this discussion, provide students with examples of bioengineer

products and applications.

• Bioengineering applies engineering principles in the fields of medicine, biology,

robotics, and any other living system.

• Examples of products that have been bioengineer are:

o Artificial Hearts

o Artificial Heart Valves

o Stents

o Catheters


Human Sight Discussion: (4 Minutes)


The power of sight is one of the five sense humans have. Sight is processed by an impressive

organ called the eye. The human eye can detect shades of light and shades of colors. When light

reflects off an object, these shades of light and shades of colors are collected by our receptors in

the eye. Receptors then send electrical pulses to the brain for processing via the optic nerve.

Figure 1.0 - The Human Eye

Reminder: It may help to describe the human eye if the model eyeball is in front of class or drawn

on the board

Simplified Definitions:

Cones – Receptors in the eye that are stimulated by colors

Rods – Receptors in the eye that are stimulated by different intensities of light

Optic nerve – A sensory nerve that allows the receptors in the eye to send electrical

pulses to the brain

Visual Cortex –Area of the brain that processes vision. This is located in the back region

of the brain. (If you fall on the back of the head and you see stars, it is

because the visual cortex of the brain was stimulated by the shock of fall)


Group Discussion: The importance of sight


Can anyone name the five human senses?

• Seeing

• Hearing

• Tasting

• Touching

• Smelling

If you were to lose the human senses of sight, how would life be different? Give a few examples

of some daily difficulties.

• Having a hard time cooking

• Having a hard time walking

• Having a hard time being aware of their own surroundings

Hand out papers and pens to each student. With the students’ eyes opened, have them write their

names on the piece of paper and draw their own hand (without sketching around their own hand).

With the students’ eyes closed, have them write their names on the piece of paper and draw their

own hand again. Ask the students if it was more difficult to write and draw with their eyes

closed.

What kind of diet can help maintain healthy eyes?

• Eating carrots can help with keeping health vision

• Carrots contain vitamin A – this is an essential vitamin for maintaining healthy vision

• Vitamin A can also be found in milk, egg yolks, and cheese

What is the difference between nearsightedness and farsightedness?

• Nearsightedness – Condition in which an individual has difficulties viewing

objects from a distance.

• Farsightedness – Condition in which an individual has difficulties viewing objects from a

close distance.

What are some animals with excellent vision?

• Eagles - has eyesight about 3-4 times better than a human

• Vultures - keen eyes for seeing far distances

• Owls - excellent night vision


Engineering Sight Discussion: (4 Minutes)


Engineers and scientist have been studying how the human eye works and functions in hopes of

finding a solution for the visually impaired. Currently, bioengineers are working to develop a

device called the artificial eye. The artificial eye is a device that allows the individual to receive

and process light, and stimulate the brain.

Group Discussion: Engineering/Technical aspects


What are some current methods to correct vision for those that suffer from farsightedness and

nearsightedness?

• Get eyeglasses

• Get contact lenses

• Laser surgery on the eye (laser surgery cuts the lens into a more preferred shape)

Can anyone name some electronic devices that perform functions similar to the human eye?

• Camera, web cams, video recorder

Engineers have thought of implementing a micro camera into the human eye. Another method

was to use electrodes. Electrodes can pick up light that are reflected off objects. Can anyone

name what body part acts similar to electrodes?

• The eyes

So how can engineers replicate receptors in the eye?

• With the use of electrodes that respond to light signals

• With the use of a camera

The human brain response and sends out electrical pulses. To communicate with the human

brain, engineers construct devices that can send and receive electrical pulses. However the

human brain is complex and not differs from person to person. Can anyone think of some

difficulties engineers must deal with?

• Engineers do not know the location in which to stimulate or receive signals to or from the

brain

• Implanting electrodes into the human eye.

• Designing electrical pulse for different individuals

• Stimulating the brain to know the difference between light, dark or even different colors.


Image Resources

• Figure 1: http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-

org/chap16/F16-01%20Human%20eye.jpg

Date: Feb 04, 2009

Time: 6:30 pm

• Figure 3: http://static.guim.co.uk/sys-

images/Guardian/Pix/pictures/2008/04/21/eye276.jpg

Date: Feb 04, 2009

Time: 6:35 pm


Artificial Eye Activity: (25 Minutes)

Learning Objectives: By the end of this lesson, students should be able to…

• Describe and identify the biological equivalent of parts of the artificial eye kit.

• Describe and identify the engineering parts of the Artificial eye kit.

• Create and use the data table to find optimal performances of a circuit

Materials: 1. Infrared LED Flashlight

2. Photodiode LED (Black)

3. Red LED

4. Breadboard

5. IC Chip

6. 2 AA Batteries

7. Battery Holder

8. Switch

9. Resistors – 68 ohm, 10 ohm, 100

ohm, 1 Kohm, 1Megohm

10. Capacitor - 1pF

11. Laminated Biology Sheet

12. Laminated Engineering Sheet

Procedures: 1. Students should be working in teams, with two students per team. Assign roles for each member

of a group: a Design Engineer and a Performance Engineer. Have the model eyeball

demonstrated in front of class.

2. Have the Design Engineer collect the necessary materials for the group. This student will follow

the illustrated Laminated Engineering Sheet instructions to construct the artificial eye onto the

breadboard.

3. While the Design Engineer is constructing the artificial eye kit, have the Performance Engineer

test the infrared LED flashlight with the model eyeball in front of class.

4. Have the Performance Engineer test the circuit. This student will place different resistors onto

the breadboard for testing. He/She will be testing the circuit for its maximum distance of the

infrared LED Flashlight operating with their artificial eye kit. Each distance will be recorded in a

data table under the Artificial Eye Activity Worksheet.

5. Have each group decide which resistor is best for the artificial eye. Then have both engineers

work together to fill out the Matching Chart portion of the Artificial Eye Activity Worksheet.


Artificial Eye Activity Worksheet Team Members:

Design Engineer: _____________________________

Performance Engineer: _____________________________

Data Tables:

Testing the Artificial Eye

Resistor Values Maximum Distance Still Working (inches) 68 Ω

10 Ω

100 Ω

1 kΩ

1MΩ

No resistor

Matching Chart:

Biological Human Eye Engineered Artificial Eye

A. Eye

B. Brain

C. Optic Nerve

____. LED Receptor

____. Wires to LED

____. Red LED


Artificial Eye Activity Worksheet Answers

Data Tables:

Testing the Artificial Eye

Resistor Values Maximum Distance Still Working (inches) 68 Ω ~3

10 Ω 0

100 Ω ~1

1 kΩ ~4

1MΩ ~10

No resistor Never Turns Off

Matching Chart:

Biological Human Eye Engineered Artificial Eye

A. Eye

B. Brain

C. Optic Nerve

_A_. LED Receptor

_C_. Wires to LED

_B_. Red LED


Concluding Discussion

Have the class go over the Artificial Eye Activity Worksheet.

Ask the students the following questions:

1. With what resistor value did the red LED stayed constantly on?

2. With what resistor value did the circuit operated the furthest with the ability to turn off?

Have the class take a poll of which resistor is best for the more optimal artificial eye circuit. The

answer should be the 1 MΩ resistor.

Ask the following questions to stimulate a discussion:

1. Can anyone guess why a person might see stars when he/she falls down on their back side

of their head? (do not allow students to test this theory)?

Ans: A blow to the back of a person’s head stimulated the optical lobe which can cause a

person to think he/she sees stars

2. What are some problems with the artificial eye stimulating the brain?

Ans: Engineers and Scientist have a hard time stimulating the exact location of the brain.

3. What is another application to the artificial eye?

Ans: Engineers can implant artificial eyes to robots

Tell the class some fun facts about the human eye:

1. A shark’s cornea is similar to that of a human’s and is sometimes used in eye surgery.

2. People generally read 25% slower from a computer screen than compared to reading

from a piece of paper.

3. All babies are color blind when they are born.

Other fun facts can be found at this website: http://www.funshun.com/amazing-facts/eye-human-body-facts.html

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