neuroophthalmology 1st part. second part include the optic nerve diseases

1. NEUR
OPHTHALM O LOGY
Prepared by
Nur Hanisah Binti Zainoren

2. OBJECTIVES
Anatomy of the visual
pathway
Lesions of the visual
pathway
Pupillary reflexes and
their abnormalities
Anisocoria

4. VISUAL PATHWAY
CONSISTS OF:

5. OPTIC NERVES
VISUAL PATHWAY
CONSISTS OF:
The fibres of optic nerve originate in
the retina - divided into the temporal &
nasal halves of the fovea centralis.
Join the optic chiasma at the
anterolateral angle

6. OPTIC NERVES
OPTIC CHIASMA
VISUAL PATHWAY
CONSISTS OF:
A flat band-like structure lying above the
pituitary fossa
In the optic chiasma, there is semi-
decussation of the nerve fibres
• Nerve fibres from the nasal side of
each retina CROSS-OVER to the
opposite side
• Nerve fibres from the temporal side of
DO NOT CROSS but pass into optic
tracts of the same side

7. OPTIC NERVES
OPTIC CHIASMA
OPTIC TRACTS
VISUAL PATHWAY
CONSISTS OF:
Originate from the postero-lateral angle of
the optic chiasma
Cylindrical bands running outwards &
backwards to end in the lateral geniculate
bodies
They consist of the temporal fibres of the
same side and the nasal fibres of the
opposite side

8. OPTIC NERVES
OPTIC CHIASMA
OPTIC TRACTS
LAT. GENICULATE BODIES
VISUAL PATHWAY
CONSISTS OF:
Oval structures situated at the
posterior end of the optic tracts
The fibres of the optic tracts end in
the lateral geniculate bodies and
new fibres of the optic radiations
originate from them

9. OPTIC NERVES
OPTIC CHIASMA
OPTIC TRACTS
LAT. GENICULATE BODIES
OPTIC RADIATIONS
VISUAL PATHWAY
CONSISTS OF:
These extend from the LGB
to the visual cortex and
consist of the axons of third-
order neurons of visual
pathway

10. OPTIC NERVES
OPTIC CHIASMA
OPTIC TRACTS
LAT. GENICULATE BODIES
OPTIC RADIATIONS
OCCIPITAL CORTEX
VISUAL PATHWAY
CONSISTS OF:
Situated above and below
the calcarine fissures in the
occipital lobes extending up
to the occipital poles

11. OPTIC NERVES
OPTIC CHIASMA
OPTIC TRACTS
LAT. GENICULATE BODIES
OPTIC RADIATIONS
OCCIPITAL CORTEX
VISUAL PATHWAY
CONSISTS OF:

13. BLOOD SUPPLY
OF THE
VISUAL
PATHWAY

14. LESIONS OF VISUAL PATHWAYS

15. LESIONS OF VISUAL PATHWAYS

16. LESIONS OF VISUAL PATHWAYS

17. LESIONS OF VISUAL PATHWAYS

18. LESIONS OF VISUAL PATHWAYS

19. LESIONS OF VISUAL PATHWAYS

20. LESIONS OF VISUAL PATHWAYS

21. LESIONS OF VISUAL PATHWAYS

22. AND
THEIR ABNORMALITIES

23. 1)LIGHT REFLEX
2)NEAR REFLEX
3)PSYCHOSENSORY REFLEX

25. 1) LIGHT REFLEX
• When light is shone to one eye, both the pupils
constrict
• Constriction of the pupil to which light is shone is
called direct light reflex
• Constriction of that other pupil is called direct light
reflex consensual (indirect) light reflex
• Initiated by rods and cones

26. LIGHT REFLEX (PATHWAY)

29. 2) NEAR REFLEX
• Occurs on looking at a near object
• Consists of TWO components:
– CONVERGENCE REFLEX
(CONTRACTION OF PUPIL ON CONVERGENCE)
– ACCOMMODATION REFLEX
(CONTRACTION OF PUPIL ON ASSOCIATED WITH ACCOMMODATION)

30. 3) PSYCHOSENSORY REFLEX
• Refers to dilatation of the pupil in response
to sensory and psychic stimuli
• Very complex
• Mechanism is not elucidated

31. ABNORMALITIES
1)AMAUROTIC LIGHT REFLEX
2)MARCUS GUNN PUPIL
3)WERNICKE’S HEMIANOPIC PUPIL
4)ARGYLL ROBERTSON’S PUPIL
5)EFFERENT PATHWAY DEFECT
6)ADIE’S TONIC PUPIL

32. 1) AMAUROTIC LIGHT REFLEX
• Lesions of the optic nerve or retina on the
affected side  complete blindness
• Absence of direct light reflex on the affected
side AND absence of indirect light reflex on
the normal side

33. 2) MARCUS GUNN PUPIL
• Presence of a relative afferent pathway
defect (RAPD) due to
– incomplete optic nerve lesions
– severe retinal disease
• Paradoxical response of a pupil to light

34. 3) WERNICKE’S HEMIANOPIC
PUPIL
• Lesion of the optic tract
• Light reflex is absent when light is thrown on
the temporal half of the retina of the affected
side and nasal half of the opposite side ;
while it is present when the light is thrown
on the nasal half of affected side and
temporal half of the opposite side

35. 4) ARGYLL ROBERTSON PUPIL
(ARP)
• Lesions in the
region of tectum
• Both pupils are
slightly small in size
• Reaction to near
reflex is present,
but light reflex is
absent

36. 5) EFFERENT PATHWAY REFLEX
• Efferent pathway defect (sphincter paralysis)
– Parasympatholytic drug (eg: atropine)
– Internal opthalmoplegia
– Third nerve paralysis
• Absence of both direct & indirect light reflex
and also near reflex on the affected side
• Presence of all reflexes on normal side

37. 6) ADIE’S TONIC PUPIL
• Due to postganglionic parasympathetic
pupillomotor damage
• Reaction to light is absent, near reflex is very
slow and tonic on the affected side
• The affected pupil is larger (anisocoria)

38. Difference between the size of two pupils
[Normal size of pupil: 3-4mm]

39. Is not caused by optic nerve lesions or
other afferent pupil pathway defects.
It is a sign of autonomic dysfunction
CAUSES:
• Physiological anisocoria
– usually minimal, both pupils react well to light;
no dilatation lag
• Pathological anisocoria
– Usually a difference of 2mm or more
– May be either due to abnormal miosis or
mydriasis of one pupil

40. EVALUATION OF ANISOCORIA:
1. Pupil size in dim and bright illumination should
be noted first
2. Pupillary light reflex should be noted
3. Pharmacological test
– Suspected parasympathetic palsy (Pilocarpine)
– Suspected sympathetic palsy (Cocaine or
Hydroxyamphetamine)

41. REFERENCES
• Comprehensive Ophthalmology, 6th Edition, A K
Khurana, JAYPEE
• http://www.derangedphysiology.com/main/requi
red-reading/neurology-and-
neurosurgery/Chapter%204.6.2.3/visual-fields-
and-lesions-visual-pathways-cn-ii
• https://www.youtube.com/watch?v=cjnStgx-tb4