Few points to consider when examining the 2nd cranial nerve- optic nerve with respect to ophthalmology

1. EXAMINATION OF THE OPTIC
NERVE
-Dr Akshay Nayak

2. Headings to consider in general
1. Visual acuity
2. Colour vision
3. Field of vision
4. Pupillary reaction
5. IOP
6. Ophthalmoscopy
7. Slit lamp
8. Fluorescein angiography
9. X ray/ct skull,pns,orbit
10. Visually evoked potential{vep}
11. OCT

3. Signs of optic nerve dysfunction
• Reduced Visual Acuity
• RAPD
• Dyschromatopsia
• Diminished light brightness sensitivity
• Diminished contrast sensitivity
• Visual field defects

4. Pupillary Reflex Pathway

5. Grades of RAPD and Causes
• +1 – initial constriction followed by early release of affected pupil
• +2- no movement initially, followed by pupillary release
• +3- immediate pupillary dilation
• +4- amaurotic eye( no light perception)
Causes-
1. Optic neuropathy
2. Extensive Retinal Damage
3. Amaurotic Eye

6. Visual Field Examination
1. Confrontational Visual Field Examination
2. Tangent Screen test or Bjerrum screen
3. Automated Perimetry
• Normal fields extend – approximately-
100deg temporally, 60deg nasally, 60deg superiorly and 70deg
inferiorly
• Blind Spot dimension-
horizontally- 7-8 *
vertically 10-11 *

7. Visual field assessment

13. • Colour Vision- Ishihara and Hardy-Rand Rittler
• Contrast sensitivity- Sloan chart and Pelli Robson chart

14. • BINOCULAR VISION AND STEREOACUITY
o ACUITY IN BINOCULAR VISION> UNIOCULAR – due to cortical
summation of visual input from both eyes
• Stereoacuity

15. Visual Evoked Potential
• Principle-electrical activity of visual cortex recorded due to retinal
stimulation
• Used in optic neuropathy especially when associated with
demyelination
• Technique-
• Flash of light(flash vep)
 Merely tells light is perceived
• Checkerboard(pattern vep)
Timing of onset of response is more important
Delay- retrobulbar neuritis(persists even when vision returns to
normal)

17. EXAMINATION OF A CASE OF PAPILLOEDEMA
Symptoms-
Systemic-headache, vomiting,convulsions etc
Ocular
• NIL , transient or persistent blurring of vision , diplopia, ocular
deviation
• Visual acuity and pupillary reactions are NORMAL for a long time.

18. • Fundus
• Early
o Blurring of disc margin and hyperemia
• Established-bilateral and equal
o Peri papillary retinal oedema
o Linear or flame shaped hemorrhages
o Circumferential retinal folds
o Venous pulsation is ABSENT
• Chronic
o Disc oedema is +4.0D.
o Vessels disappear in the swollen and hyperaemic disc
o Hard exudates at macula
• Late
o Sheating of blood vessels,pallor and waxy discoloration of disc
o Post pappiloedematous optic atrophy replaces hyperemic disc

20. • FIELD CHANGES
• EARLY- enlargement of blind spot
• LATE- peripheral constriction
 FUNDUS FLUORESCEIN ANGIOGRAPHY
• Diffuse fluorescence of head(due to retention of dye in retinal veins
and oedematous fluid over disc)

21. Fundus fluorescein angiography of the left eye with papilloedema. A rapid series of fundus photographs follow the
intravenous injection of a fluorescent contrast agent. In true disc swelling, the frames (A – D) show progressively
increased intensity and area of fluorescence at the disc. This shows fluorescein leakage from the oedematous disc.

22. EXAMINATION OF A CASE OF OPTIC NEURITIS
• Symptoms
1. Sudden loss of vision
2. Light in room appears dim in affected eye
3. Generally unilateral
4. Scotoma
5. Pain on movement of eye
6. Loss of color vision

23. • Signs
1. Reduced visual acuity
2. Reduced/Faulty Color vision
3. Depth perception is faulty
4. Pupils- Size is normal in spite of loss of vision
RAPD
Consensual and near reflexes maybe normal

24. Fundus
• Early- No change or slight hyperemia of disc.
• Fully developed- elevation of disc but not more than +3D
Physiological Cup is lost
Linear or superficial hemorrhages
Severe—Macular star
SLE- Vitreous haze in front of disc
• Late- pale disc, margins remain blurry, vessels narrow and sheated.
Post neuritic optic atrophy
Diagnosis of retrobulbar neuritis

27. Examination of an eye with optic atrophy
• TO Diagnose-
1. Pallor of disc
2. Decreased vision
3. Pupillary changes
4. Field changes
5. Defective colour vision

28. Special types of Optic Atrophy
• Temporal Pallor-
 Architecture of disc is normal.
 Congenital anomalies of disc and macula, cerebromacular degeneration,
retrobulbar neuritis etc
• Segmental Pallor- One segment adjacent to juxtapapillary choroiditis
• Altitudinal pallor
 Ischemic optic neuropathy
• Bow tie pallor
 Chiasmal , retrochaismal and pre-geniculate lesions
 Bitemporal hemianopia

29. Temporal pallor in optic atrophy

30. Band or bowtie atrophy of the optic disc indicates
the presence of a lesion in the contralateral optic
tract involving crossed retinal fibers nasal to the
fovea

31. Thank yOU