This document provides an overview of the anatomy and clinical assessment of the optic nerve in 3 paragraphs: 1) It describes the anatomy of the optic nerve, including its origin from the ganglion cells and path from the optic disc to the optic chiasm. It is composed of over 1 million axons and is divided into intraocular, intraorbital, intracanalicular, and intracranial portions. 2) Clinical assessment of the optic nerve involves testing visual acuity, color vision, visual fields, and the pupillary light reflex. Signs of optic nerve pathology include an afferent pupillary defect. 3) Different pathologies like papilledema, optic neuritis, and optic

1. E-mail: Shaf3y_h@hotmail.com
facebook/shafie eye clinic
Symptoms & Signs in Clinical Medicine
By/Mohamed Ahmed El –Shafie
Assistant Lecturer in ophthalmology department KafrELShiekh University

2. Anatomy of optic nerve
• Optic nerve- more than 1 million axons.
• Consisting of axons originating from ganglion
cells.
• Starts from optic disc upto optic chiasma.
• Contains the afferent fibers of light reflex.
• Elongated tract of white matter
• Not covered by neurilemma.
2

3. • Optic nerve divided in topographic areas:
Intraocular portion.
Intraorbital portion.
Intracanalicular portion.
Intracranial portion.
3

4. 4

5. Intraocular optic nerve
• 1 mm in length.
• 1.5 mm diameter.
• Which expands approximately 3-4 mm behind
the sclera.
5

6. Intraorbital optic nerve
Relation of ophthalmic artery
At the optic foramen: inferior and lateral
Lateral to optic nerve (in posterior orbit)
Inferior division of 3rd
nerve-Sixth Nerve
Ciliary ganglion
Nasociliary artery
6

7. At the orbital apex – optic nerve surrounded
by annulus of Zinn.
Blood supply: Ophthalmic artery with
meningeal branches
7

8. Intracanalicular optic nerve
• 9 mm
• Tightly fixed within the canal (compressive
optic neuropathy Optic nerve edema)
• Blunt trauma
Blood supply: Pial branches from ophthalmic
artery. 8

9. Intracranial optic nerve
• Length-10mm
• Diameter-4.5mm
Extends post & medially ascending at an angle
of 45º to join the chiasma
Blood supply: pial vessels arising from ICA
branches from ant cerebral and anterior
communicating artery 9

11. Normal optic disc
- Color: Orange or pink
- Margin
- Counter
- Crescent
- Distribution of veins.

12. Why the normal disc is pink?
• Thickness and the
cytoarchitecture of fiber
bundles passing
between glial columns
containing capillaries
12

13. • Pathologies of the optic nerve, even though
not always detected on ophthalmoscopic
exam, may compromise its function and
cause the following sign;

14. Visual Acuity
 Near vision
- Reading from a book
 Far vision
- Snellen chart.
 - Ishihara charts

15. Dyschromatopsia
• Impaired color vision = 94%
• Desaturation
• – eg: red = dark/ beached
• Distinguishes b/w macular lesion

16. confrontation

17. Kinetic perimetry Static perimetryKinetic perimetry Static perimetry

18. • all patients show V.F abnormalities in acute phase
Central ⁺⁺⁺, peripheral⁺, particular region⁺
• If Vn severely impaired – confrontation test
• Vision improved –
• kinetic Goldman Perimetry ( only central scotoma)
• Automated static Perimetry
• Focal defect –
• Altitudinal
• Arcaute
• Nasal step defect

19. • Stimulus
• Receptors
• Afferent
• Center
• Efferent
• Effector organ
• Effect
Pup. light reflex

20. VEDIO
VEDIO

21. Afferent pupillary defect
• In the absence of an optic nerve lesion in the fellow eye, RAPD
can be demonstrated by swinging flash light
• -ve RAPD in recurrent attacks
Causes:Causes:
• Optic neuropathyOptic neuropathy
• Total retinal detachmentTotal retinal detachment
• Dense vitreous haemorrhageDense vitreous haemorrhage
• Dense amblyopiaDense amblyopia

22. VEDIO

23. Contrast sensitivity
• - good for subclinical ON

24. Optic Disc SwellingOptic Disc Swelling
How do you approach?How do you approach?

25. PapilloedemaPapilloedema vsvs Optic NeuritisOptic Neuritis

26. Papilloeodema
 Definition ,
Non-inflammatory swelling of Optic disc
 Causes
1. Raised Intracranial Pressure:
- Space-occupying lesions
-Occlusion of :retinal veins
cavernous sinus
-Other cause.

27. Optic Neuritis
(ON)• Inflammation of optic nerve - ON
• Associated with swollen disc – papillitis
• Normal disc – retro bulbar ON

28. Papilledema Optic neuritis AION
increased ICP Inflammatory swelling Vascular accident (occlusion of
short posterior ciliary artery
causing infarction
Brain tumors , hematomas,
meningitis
Multiple Sclerosis is highly
associated
Hypertension, giant cell arteritis,
hypercoagulable state
Bilateral , may be
asymmetric
Unilateral Unilateral
28
Headache, nausea, vomittingHeadache, nausea, vomitting
No visual loss usually,No visual loss usually,
only enlarged blind spotonly enlarged blind spot
Retrobulbar pain on ocularRetrobulbar pain on ocular
movement, early centralmovement, early central
scotoma, decreased acuity,scotoma, decreased acuity,
impaired color vision,impaired color vision,
presence of APDpresence of APD
Acute painless visual loss, usuallyAcute painless visual loss, usually
hemialtitudinal defect involvinghemialtitudinal defect involving
the lower visual fieldthe lower visual field
Variable degree of disc
swelling, hemorrhages
Fewer hemorrhages and
cotton wool spots
Pale segmental swelling and
splinter hemorrhages at its
margins
Prognosis usually good if
primary cause of increased
ICP is treated
Vision usually returns to
normal
Poorer prognosis, permanent loss.
Second eye is involved in one
third of cases.

29. OPTIC ATROPHY
Degeneration of the optic nerve
occurs as an end result of any pathologic process
that damages axons
Ophthalmoscopic classification
 Primary optic atrophy
Secondary optic atrophy
Consecutive optic atrophy
Glaucomatous optic atrophy

30. Primary optic
atrophy
Consecutive
optic atrophy
Secondary optic
atrophy
Glaucomatous
optic atrophy
chalky white or
white
Disc appears
yellow waxy
dirty white in colour Pale disc
Margins are sharply
outlined
edges are not
so sharply
defined
Edges are blurred,. Edges well defined
Lamina cribrosa is
clearly seen at the
bottom of the
physiological cup
physiological cup is
obliterated
deep and wide
cupping of the optic
disc and nasal shift of
the blood vessels
Major retinal vessels
and surrounding
retina are normal
Retinal vessels
are attenuated
vessels are
attenuated and
perivascular
sheathing
Normal

32. 32