1. Central retinal artery and vein Optic nerve Vitreous body Conjunctiva
Visual Pathways
Eye
Lens
Cornea
Iris
Suspensory ligaments
Ciliary body
Ciliary muscle
Retina
Choroid
Sclera
Subarachnoid space
Central retinal artery and vein
Optic nerve
Vitreous body
Conjunctiva
Retina - contains
Pigment epithelial cells- absorb light that passes through the retina
First neuron
Rods- vision in light of low intensity
Cones- visual acuity and color vision
Second neuron
Bipolar- second neurons of visual pathway
Ganglion
Ganglion- third neurons of visual pathway
Neuroanatomy OC TH 5090/PH TH K. Bo Foreman PT, PhD

2. Optic disc- Area optic nerve exits retina (blind spot- no receptors)
Additional areas:
Optic disc- Area optic nerve exits retina (blind spot- no receptors)
Macula lutea- central region of the retina
Fovea centralis- area of the central part of the retina that is indented and contains mainly cones for visual acuity
Visual Pathway-
Light travels through retina from internal to external exciting the rods and cones
Impulse is transferred from rods and cones to bipolar cells
Bipolar cells synapse on the dendrites of the ganglion cells
Neuroanatomy OC TH 5090/PH TH K. Bo Foreman PT, PhD

3. Visual Pathway-
Ganglion cells form the optic nerve at the level of the optic disc
Optic nerves combine to form optic chiasm
Enters lateral geniculate body to synapse
Visual Pathway- forth order neurons
Cell body located in the lateral geniculate body
Axon travels posteriorly (optic radiations)
Terminates in the visual cortex in the occipital lobe

4. 1. Right eye blindness - trauma, optic neuritis
2. Bitemporal hemianopsia - pituitary tumors
3. Right nasal hemianopsia - pressure by aneurysm of internal carotid artery
4. Left homonymous hemianopsia - abscess or tumor of temporal lobe
5. Left homonymous hemianopsia - anterior choroidal artery dysfunction
6. Left homonymous superior quadratic anopsia - temporal or occipital lobe dysfunction
7. Left homonymous inferior quadratic anopsia - parietal or occipital lobe tumor
8. Left homonymous hemianopsia with macular preservation - posterior cerebral artery dysfunctions, tumors, trauma 1. 2. 3. 4. 5. 6. 7. 8.
Neuroanatomy OC TH 5090/PH TH K. Bo Foreman PT, PhD

5. Neuronal elements of the retina Optic nerve Optic chiasm Optic tract
Lecture 14 - Visual
Visual Reflexes
Light reflex (constriction- parasympathetic): when light enters the pupil the pupil constricts
Neuronal elements of the retina
Optic nerve
Optic chiasm
Optic tract
Enter the brachium of the superior colliculus (superior brachium)
Pretectal region
Oculomotor nuclear complex (Edinger-Westphal nucleus)
Preganglionic parasympathetic axons to the ciliary ganglion behind eye
Short ciliary nerves
Terminate on the constrictor muscle of the iris
Neuroanatomy OC TH 5090/PH TH K. Bo Foreman PT, PhD

6. White communicating rami Ascend sympathetic trunk
Lecture 14 - Visual
Visual Reflexes
Light reflex (dilation- sympathetic): when the pupil widens. Occurs passively when parasympathetic tone decreases and actively when sympathetic tone increases
Hypothalamus
Spinal cord (T1)
Ventral root
White communicating rami
Ascend sympathetic trunk
Synapse in superior cervical ganglion with post-synaptic sympathetic ganglion
Travel in the carotid plexus
Terminate on the dilator muscle of the iris
Neuroanatomy OC TH 5090/PH TH K. Bo Foreman PT, PhD

7. Convergence of the eyes Pupillary constriction Thickening of the lens
Visual Reflexes
Accommodation reflex: Process in which a clear visual image is maintained as gaze is shifted from a distant to a near point
3 components
Convergence of the eyes
Pupillary constriction
Thickening of the lens
Initiated by occipital cortex
Impulses go to:
Edinger-Westphal nucleus for changes in the lens and pupil (parasympathetic)
Somatic nuclei: for convergence of the eyes (medial rectus
Neuroanatomy OC TH 5090/PH TH K. Bo Foreman PT, PhD