Name: __________________
Partner: ____________________
Date: ____________________
Eye Dissection Lab
Purpose
What is the purpose of this lab?
Materials
After reading the procedures carefully, list all materials that you would need in this
lab.
Safety Precautions
List at least 3 things that one should be aware of in order to do this lab safely.
Procedure
1. Gather all materials that you will need. Place them neatly on your table. Check
to see if your dissection tray has all of the following (forceps, a probe,
scissors, a razor blade). DO NOT begin until your teacher has checked to see if
you can be given the go-ahead.
2. On a piece of blank paper and divide it into 12 equal boxes and label them:
Fat
Muscle
Optic Nerve
Retina
Choroid and Tapetum
Vitreous Humour
Iris
Lens
Aqueous Humour
Cornea
Sclera
Your names
Advisory
3. Put on your gloves and your safety goggles. Rinse the sheep eye in running
water to remove the preservation liquid and dry it with a paper towel.
4. Examine the external features of the eye. With your partner, locate the
following parts – cornea, sclera, muscle (brown), fatty tissue
Name: __________________
Partner: ____________________
Date: ____________________
(yellow/white), optic nerve, eye-lid. There are four (humans have six)
external muscles to move the eyeball around the socket while the fatty tissue
cushions the eye. When the sheep was alive, the cornea was clear. If the optic
nerve is not visible use your forceps to move the fatty tissue and muscles
around until the nerve is exposed.
5. Using your scissors, try and remove as much muscle and fatty tissue as you
can. Place a sample of each onto your piece of paper in the appropriate box
and get your teacher to check it. Answer Observation Question #1.
6. Carefully cut out a portion of the optic nerve and try to pinch it with your
fingers and answer Observation Question #2. Place it onto the paper and
get your teacher to check it.
7. Place your eye specimen in the dissection tray. Turn the specimen so the
cornea is on your left and the optic nerve on your right. With your razor
blade, make an incision in the middle.
8. Now use your scissors and insert them into the slit you made with your razor
blade. Cut the sclera with a shallow snipping motion. Turn the eye as you
continue the cutting action until you have cut all the way around. Remember
the vitreous humour is inside! Drain the vitreous humour onto your piece of
paper and get your teacher to check it. Answer Observation Question #3.
Name: __________________
Partner: ____________________
Date: ____________________
9. We will examine the back half of the eye first. Use your forceps or probe to
carefully lift and pull the retina back from the underlying choroid cover.
Answer Observation Question #4.
10. Carefully pull the retina out and place it on the sheet of paper. Get your
teacher to check it.
11. Behind the retina is the choroid coat. It provides blood, oxygen, and nutrients
to the rest of the eye. Answer Observation Question #5. Using your probe
and/or forceps, gently pull off the choroid coat and place it on the paper.
Also, cut out a portion of the sclera and place it on the paper. Get your
teacher to check.
12. Now focus your attention to the other hemisphere – the front of the eye
specimen. Carefully drain and scrape out any remnants of vitreous humour so
that you can clearly locate the lens, ciliary body, iris, and pupil.
13. Carefully remove the lens from the eye and drain the aqueous humour onto
your paper. Typically, the lens is transparent. However, with aging, a
condition called cataract occurs and makes it cloudy. The condition could be
Name: __________________
Partner: ____________________
Date: ____________________
cured by replacing the lens with a stiff, artificial one. If you want, rinse the
lens with water. Answer Observation Question #6. Place the lens onto your
paper and get your teacher to check.
14. Gently detach the iris from the eye and take a close look at it. Answer
Observation Questions #7 and #8. Place it on your paper and get your
teacher to check.
15. What’s left to investigate should be the cornea. Using your probe or a razor
blade, poke or cut through the cornea. Answer Observation Question #9.
Place the cornea on your paper and get your teacher to check.
16. Time to clean up. First, make sure your teacher has checked off all the boxes
on your paper towel. Wrap everything up with the paper towel and place it on
one hand. Carefully peel the glove off that hand so that it will be inside out
and act as a pouch to hold all the eye parts. Put the pouch in the other hand
and peel it inside out. Tie a knot in your glove and place it in the designated
garbage bag.
17. In the sink, rinse out your dissection tray as well as all of the tools and dry
them off with paper towels.
18. Place a piece of clean, dry paper towel at the bottom of the dissection tray and
place all tools on top of it. Return tray to the designated area of the room.
19. Using a damp (NOT dripping wet!) paper towel and soap or disinfectant,
thoroughly wipe down your table area and other surfaces that may be
contaminated. Dispose the paper towel into the designated garbage bag.
20.Wash your hand with soap and water thoroughly. Return to your table area
and begin working on your lab report. You have now completed a dissection of
a sheep’s eye! 
Observations
Answer them completely on the good copy of your lab report.
1. What do you notice about the difference between muscle and fat? Use a
sketch to help you if you want.
2. Describe what you see at the end of the optic nerve when you pinched it.
3. Describe the vitreous humour in as much detail as possible.
4. The retina is only firmly attached to the choroid at one place. What do you
think this place is called?
5. The choroid coat on humans is completely black to prevent unnecessary light
from reflecting back onto the retina. Sheep (and some animals) have
tapetum on the choroid that enables night vision. What does the tapetum
look like?
6. Describe the lens in as much detail as possible. What happens when you
bounce it on a hard surface? What does that tell you?
Name: __________________
Partner: ____________________
Date: ____________________
7. How does a sheep’s pupil compare to a human pupil?
8. What colour is the sheep’s iris? Is it the same on both sides?
9. What did you notice about the texture of the cornea?
Analysis
Answer the following questions in complete sentences.
1. Why didn’t you have to worry about cutting and accidentally damaging the
sclera when you are removing the external muscles and fatty tissue?
2. Humans have 2 more external muscles than sheep. What advantage does it
give us?
3. What happens to the pupil when there’s a lot of light? Little light?
4. Why is the lens flexible?
5. Name the three parts that the eye uses to focus light to produce a clear
image on the retina. What do you think happens if any of them do not work
correctly? What do you think one might need to correct it?
Evaluation
Answer the following questions in complete sentences. This part should be answered
individually.
1. Did you run into any difficulties or make any mistakes? What could cause
them during the lab? How could you prevent the mistakes and make the
experiment easier the next time?
2. When Leonardo da Vinci first learned about the human eye through
dissection, he must have had some questions that he still wondered about
afterwards. What questions do you have about the eye?
3. How even did you and your partner share the work in this lab? Indicate
using the bar below.
Name: __________________
Partner: ____________________
Date: ____________________
Lab Report Rubric
Accomplished
Exemplary
Purpose/
Materials
 Question/purpose is
erroneous or irrelevant.
 No materials listed
Practicing
 Question/purpose is
partially identified, and is
stated in a somewhat
unclear manner.
 Some materials listed
according to the
procedures.
Developing
 Question/purpose is
identified, but is stated in a
somewhat unclear manner.
 Most materials listed
according to the
procedures.
 Question/purpose is clearly
identified and stated.
 All materials are listed
according to the
procedures.
Procedure
 Participation was
minimal OR student was
hostile about
participating.
 Safety procedures were
ignored.
 None of the procedure
steps are carried out.
 Did the lab but did not
appear very interested.
Focus was lost on several
occasions.
 Lab is carried out with
some attention to relevant
safety procedures.
 Some procedure steps are
not carried out.
 Used time well and stayed
focused on the experiment
most of the time.
 Lab is generally carried out
with attention to relevant
safety procedures.
 All procedure steps are
carried out, but not in order.
 Used time well in lab and
focused attention on the
experiment.
 Lab is carried out with full
attention to relevant safety
procedures.
 All procedure steps are
carried out in order.
Observation
 Is not able to identify
parts of the eye.
 None of the observation
questions are correctly
answered
 Able to identify some parts
of the eye and correctly
place them on the paper.
 Some observation questions
are answered correctly.
 Able to identify most parts
of the eye and correctly
place them on the paper.
 Most observations are
answered correctly.
Analysis
 None of the analysis
questions are correctly
answered.
 Some analysis questions are
answered correctly.
 Most analysis questions are
answered correctly.
 Able to identify all parts of
the eye and correctly place
them on the paper.
 All observation questions
are answered correctly,
clearly, and as detailed as
possible.
 All analysis questions are
answered correctly and
clearly; may demonstrate
insight and connections to
other science ideas.
Evaluation
 There is no discussion of
errors and/or difficulties.
 Experimental errors and
difficulties are mentioned.
 Experimental errors (with
possible effects) and
difficulties (with possible
causes) are discussed.
 Experimental errors (with
possible effects),
difficulties (with possible
causes), and ways to
improve are discussed.
Appearance/
Organization
 Lab report is handwritten
and looks sloppy with
cross-outs, multiple
erasures and/or tears and
creases.
 More than 4 errors in
spelling, punctuation and
grammar in the report.
 Lab report is neatly
handwritten or typed, but
formatting does not help
visually organize the
material.
 Four errors in spelling,
punctuation and grammar
in the report.
 Lab report is neatly
handwritten or typed.
 Two or three errors in
spelling, punctuation and
grammar in the report.
 Lab report is typed and uses
headings and subheadings
to visually organize the
material.
 One or fewer errors in
spelling, punctuation and
grammar in the report.