The document describes several experiments testing the effects of different eye drugs on rabbit eyes. In the first experiment, homatropine was found to be mydriatic (causing pupil dilation) and cycloplegic (paralyzing the ciliary muscle). Phenylephrine was found to be mydriatic. Pilocarpine was found to be miotic (causing pupil constriction). Lignocaine was found to be a surface anesthetic agent that caused loss of the corneal reflex over time but no change in pupil size. The document provides procedures, observations, and inferences for each drug tested.

1. RABBIT EYE EXPERIMENTS

2. EFFECT OF HOMATROPINE ON RABBIT EYE
• Aim: To test the effect of homatropine on
rabbit’s eye
• Given solution: Normal saline (0.9%)
–Homatropine solution
• Requirements: pen torch, measuring scale,
cotton swab, dropper

3. Procedure
• A healthy rabbit was taken and kept on the table facing dark
side of room. Then the eyelashes of rabbit is trimmed. One
eye is taken as control eye and other as test eye. The pupil
size is measured in mm in both the eyes. Light and corneal
reflex was tested in both the eyes. To the control eye 3 drops
of NS was added and to the test eye 3 drops of homatropine
was added. Size of pupil, light reflex and corneal reflex was
tested in both eyes for every 5 min for half hour. Results were
entered in tabular column.

4. Observation
Time
(min)
CONTROL
EYE
Pupil size
(mm)
Light
reflex
Corneal
reflex
TEST EYE
Pupil size
(mm)
Light
reflex
Corneal
reflex
0 6 + + 6 + +
5 6 + + 7 + +
10 6 + + 8 - +
15 6 + + 9 - +
20 6 + + 10 - +
25 6 + + 10 - +
30 6 + + 10 - +

5. Inference
• In the control eye, there is no change in size of pupil. Light
reflex and corneal reflex are present throughout the
experiment
• In the test eye, there is gradual increase in size of pupil. Light
reflex is absent after 10 min and corneal reflex is present
throughout the experiment.
• Hence the given drug homatropine is mydriatic and
cycloplegic.

6. EFFECT OF PHENYLEPHRINE ON RABBIT EYE
• Aim: To test the effect of phenylephrine on rabbit’s
eye
• Given solution: Normal saline (0.9%)
– Phenylephrine solution – 10%
• Requirements: pen torch, measuring scale, cotton
swab, dropper

7. Procedure
• A healthy rabbit was taken and kept on the table facing dark
side of room. Then the eyelashes of rabbit is trimmed. One
eye is taken as control eye and other as test eye. The pupil
size is measured in mm in both the eyes. Light and corneal
reflex was tested in both the eyes. To the control eye 3 drops
of NS was added and to the test eye 3 drops of phenylephrine
was added. Size of pupil, light reflex and corneal reflex was
tested in both eyes for every 5 min for half hour. Results were
entered in tabular column.

8. Time
(min)
CONTROL
EYE
Pupil size
(mm)
Light
reflex
Corneal
reflex
TEST EYE
Pupil size
(mm)
Light
reflex
Corneal
reflex
0 8 + + 8 + +
5 8 + + 8 + +
10 8 + + 9 + +
15 8 + + 10 + +
20 8 + + 11 + +
25 8 + + 11 + +
30 8 + + 11 + +
Observation

9. Inference
• In the control eye, there is no change in size of pupil. Light
reflex and corneal reflex are present throughout the
experiment
• In the test eye, there is gradual increase in size of pupil. Light
reflex and corneal reflex is present throughout the
experiment.
• Hence the given drug phenylephrine is mydriatic.

10. EFFECT OF PILOCARPINE ON RABBIT EYE
• Aim: To test the effect of pilocarpine on rabbit’s eye
• Given solution: Normal saline (0.9%)
– pilocarpine solution (1%)
• Requirements: pen torch, measuring scale, cotton
swab, dropper

11. Procedure
• A healthy rabbit was taken and kept on the table facing dark
side of room. Then the eyelashes of rabbit is trimmed. One
eye is taken as control eye and other as test eye. The pupil
size is measured in mm in both the eyes. Light and corneal
reflex was tested in both the eyes. To the control eye 3 drops
of NS was added and to the test eye 3 drops of pilocarpine
was added. Size of pupil, light reflex and corneal reflex was
tested in both eyes for every 5 min for half hour. Results were
entered in tabular column.

12. Time
(min)
CONTROL
EYE
Pupil size
(mm)
Light
reflex
Corneal
reflex
TEST EYE
Pupil size
(mm)
Light
reflex
Corneal
reflex
0 9 + + 9 + +
5 9 + + 7 + +
10 9 + + 5 + +
15 9 + + 5 + +
20 9 + + 4 + +
25 9 + + 4 - +
30 9 + + 4 - +
Observation

13. Inference
• In the control eye, there is no change in size of pupil. Light
reflex and corneal reflex are present throughout the
experiment
• In the test eye, there is gradual decrease in size of pupil. Light
reflex is present initially but later it was not elicited. Corneal
reflex is present throughout the experiment.
• Hence the given drug pilocarpine is miotic.

14. Effect of lignocaine on rabbit eye
• Aim: To test the effect of lignocaine on rabbit’s
eye
• Given solution: Normal saline (0.9%)
– lignocaine solution (4% topical)
• Requirements: pen torch, measuring scale,
cotton swab, dropper

15. Procedure
• A healthy rabbit was taken and kept on the table facing dark
side of room. Then the eyelashes of rabbit is trimmed. One
eye is taken as control eye and other as test eye. The pupil
size is measured in mm. in both the eyes. Light and corneal
reflex was tested in both the eyes. To the control eye 3 drops
of NS was added and to the test eye 3 drops of lignocaine was
added. Size of pupil, light reflex and corneal reflex were tested
in both eyes for every 5 min for half hour. Results were
entered in tabular column.

16. Time
(min)
CONTROL
EYE
Pupil size
(mm)
Light
reflex
Corneal
reflex
TEST EYE
Pupil size
(mm)
Light
reflex
Corneal
reflex
0 7 + + 7 + +
5 7 + + 7 + +
10 7 + + 7 + +
15 7 + + 7 + +
20 7 + + 7 + -
25 7 + + 7 + -
30 7 + + 7 + -
Observation

17. Inference
• In the control eye, there is no change in size of pupil. Light
reflex and corneal reflex are present throughout the
experiment
• In the test eye, there is no change in size of pupil. Light reflex
is present throughout the experiment. Corneal reflex was lost
in 20 min.
• Hence the given drug lignocaine is surface anaesthetic agent.

18. Probable Questions
• What are local anaesthetics
• List differences between LA & GA
• Name some surface anaesthetics
• Therapeutic uses of LA
• Adverse effects of LA
• Which is the longest acting LA

19. Probable Questions
• Various dosage forms of lignocaine with their
strengths and uses
• What is eutectic mixture, mention its uses
• Rationale of using lignocaine with adrenaline
and contraindications for the same
• For removal of foreign body from the eye will
you use xylocaine or procaine – justify
• What is reverse tolerance with example