optic nerve clinical significance
TRANSCRIPT
![Page 1: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/1.jpg)
E-mail: [email protected] facebook/shafie eye clinic
Symptoms & Signs in Clinical Medicine
By/Mohamed Ahmed El –Shafie
Assistant Lecturer in ophthalmology department KafrELShiekh University
![Page 2: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/2.jpg)
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
![Page 3: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/3.jpg)
• Optic nerve divided in topographic areas:
Intraocular portion.Intraorbital portion.Intracanalicular portion.Intracranial portion.
3
![Page 4: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/4.jpg)
4
![Page 5: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/5.jpg)
Intraocular optic nerve
• 1 mm in length.• 1.5 mm diameter.• Which expands approximately 3-4 mm behind
the sclera.
5
![Page 6: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/6.jpg)
Intraorbital optic nerve
Relation of ophthalmic arteryAt the optic foramen: inferior and lateral
Lateral to optic nerve (in posterior orbit)
Inferior division of 3rd nerve-Sixth NerveCiliary ganglionNasociliary artery
6
![Page 7: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/7.jpg)
At the orbital apex – optic nerve surrounded by annulus of Zinn.
Blood supply: Ophthalmic artery with meningeal branches
7
![Page 8: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/8.jpg)
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
![Page 9: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/9.jpg)
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
![Page 10: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/10.jpg)
![Page 11: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/11.jpg)
Normal optic disc
- Color: Orange or pink
- Margin- Counter- Crescent- Distribution of veins.
![Page 12: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/12.jpg)
Why the normal disc is pink?
• Thickness and the cytoarchitecture of fiber bundles passing between glial columns containing capillaries
12
![Page 13: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/13.jpg)
• Pathologies of the optic nerve, even though not always detected on ophthalmoscopic exam, may compromise its function and cause the following sign;
![Page 14: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/14.jpg)
Visual Acuity Near vision
- Reading from a book
Far vision
- Snellen chart.
- Ishihara charts
![Page 15: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/15.jpg)
Dyschromatopsia • Impaired color vision = 94%• Desaturation
• – eg: red = dark/ beached
• Distinguishes b/w macular lesion
![Page 16: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/16.jpg)
confrontation
![Page 17: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/17.jpg)
Kinetic perimetry Static perimetry Kinetic perimetry Static perimetry
![Page 18: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/18.jpg)
• 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
![Page 19: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/19.jpg)
• Stimulus• Receptors• Afferent• Center• Efferent• Effector organ• Effect
Pup. light reflex
![Page 20: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/20.jpg)
VEDIO
VEDIO
![Page 21: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/21.jpg)
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
![Page 22: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/22.jpg)
VEDIO
![Page 23: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/23.jpg)
Contrast sensitivity
• - good for subclinical ON
![Page 24: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/24.jpg)
Optic Disc SwellingOptic Disc Swelling How do you approach? How do you approach?
![Page 25: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/25.jpg)
Papilloedema Papilloedema vsvs Optic Neuritis Optic Neuritis
![Page 26: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/26.jpg)
Papilloeodema Definition , Non-inflammatory swelling of Optic disc Causes1. Raised Intracranial Pressure:
- Space-occupying lesions-Occlusion of :retinal veins cavernous sinus-Other cause.
![Page 27: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/27.jpg)
Optic Neuritis (ON) • Inflammation of optic nerve - ON
• Associated with swollen disc – papillitis
• Normal disc – retro bulbar ON
![Page 28: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/28.jpg)
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, vomittingNo visual loss usually,No visual loss usually, only enlarged blind spot only enlarged blind spot
Retrobulbar pain on ocular Retrobulbar pain on ocular movement, early central movement, early central scotoma, decreased acuity, scotoma, decreased acuity, impaired color vision,impaired color vision,presence of APDpresence of APD
Acute painless visual loss, usually Acute painless visual loss, usually hemialtitudinal defect involving hemialtitudinal 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.
![Page 29: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/29.jpg)
OPTIC ATROPHYDegeneration of the optic nerveoccurs as an end result of any pathologic process that damages axons
Ophthalmoscopic classification Primary optic atrophySecondary optic atrophyConsecutive optic atrophyGlaucomatous optic atrophy
![Page 30: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/30.jpg)
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
![Page 31: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/31.jpg)
![Page 32: Optic nerve Clinical significance](https://reader036.vdocument.in/reader036/viewer/2022062310/5886cec81a28abcc7d8b7efb/html5/thumbnails/32.jpg)
32