Gghj

1. PUPILLARY REFLEXES

2. PUPILLARY REFLEXES
• Pupillary reflex allows the eye to adjust the amount
of light reaching the retina and protects the
photoreceptors from bright lights

3. • Two types
1. Pupillary light reflexes
2. Pupillary accommodation reflex

4. • Two types of pupillary light reflexes :
1. Direct pupillary light reflex : If the light is focused
on to one eye, constriction occurs in the same eye
2. Indirect (Consensual) light reflex : If the light is
focused on to one eye, the other eye’s pupil also
constrict

5. Photoreceptors (rods and cones) stimulated (by light stimuli)
PATHWAY FOR PUPILLARY LIGHT REFLEXES
Optic nerve
Optic tract
Pretectal nucleus (between thalamus and midbrain)
Edinger-Westphal nucleus
Oculomotor nerve
Ciliary ganglion
Sphincter pupillae

6. ACCOMMODATION REFLEX

7. ACCOMMODATION REFLEX
• When, the eye is focusing on a close or near object,
the lens become more curved, causing greater
refraction of the light rays
• The increase in the curvature of lens for near vision
is called “accommodation”

8. • Changes takes place in the eyes for near vision :
1. Constriction of the pupil
2. Convergence of the eye ball
3. Bulging of lens (increase curvature of lens)

9. Photoreceptors (rods and cones) stimulated (by light stimuli)
PATHWAY FOR PUPILLARY LIGHT REFLEXES
Optic nerve
Optic tract
Primary visual cortex (Area 17)
Frontal eye field (Area 8)
Oculomotor nucleus
Oculomotor nerve
Muscles of accommodation (Medial rectus, ciliary muscle, sphincter
pupillae)
(Corticonuclear fibers)
(Superior longitudinal fasciculus)

10. • Contraction of ciliary muscle : Increase the anterior
curvature of lens
• Contraction of constrictor pupillae : Constriction of
pupil
• Contraction of medial rectus : Convergence of
eyeballs