Neuro-ophthalmology ReviewFirst Hour—

Afferent Visual System

Thomas M. Bosley, MD

Department of Ophthalmology

King Saud University

Neuro-ophthalmology

• Afferent• Efferent• Other

• Anatomy• Examination• Diagnoses• Tests

Afferent Anatomy

• Anatomy• Examination• Diagnoses• Tests

Human Afferent Visual

System

Polyak, THE VERTEBRATE VISUAL SYSTEM, 1957

Afferent Anatomy

Afferent Visual System

• Anatomy• Examination• Diagnoses• Tests

• Visual acuity• Color vision• Visual field• Pupil examination• Fundoscopy

Examination

• Visual acuity• Color vision• Visual field• Pupil examination• Fundoscopy

Distance

NearIshihara

AOCConfrontation

Goldmann

HumphreyDirect ophthalmoscopy

Slit lamp and lens

Indirect ophthalmoscopy

Light

Dark

Afferent Visual System

• Anatomy• Examination• Diagnoses• Tests

• Compression

• Trauma

• Inflammation

• Ischemia

• Congenital and genetic problems

Afferent Diagnoses

• Compression

• Trauma

• Inflammation

• Ischemic

• Congenital and genetic problems

Intraorbital ON

Intracranial ON

Optic chiasm

Optic tract

Posterior afferent system

35 yo woman

• Reported 3 months of gradual visual loss OU

• 7 months pregnant• Rapid visual loss OU

over 1 week before N-O evaluation

• VA at presentation OD 20/40 and OS NLP

Normal sagittal scan

Post-op visual fields

60 yo physician

• c/o mild visual blurring

• No DM, no HBP; impotence x 10 years

• Good visual acuity and color vision

• Mild temporal pallor OU

• Prolactin level of 11,000

HVF

MRI

Afferent Diagnoses

• Compression

• Trauma

• Inflammation

• Ischemic

• Congenital and genetic problems

Globe

Intraorbital ON

Optic canal

Optic chiasm

Occipital lobe

Before Temporal Lobectomy

After temporal lobectomy

27 yo man

• Driving his car at night 9 years before

• Hit a camel

• Substantial head trauma

• Hospitalized for 2 months

• Has noticed decreased vision in his right eye

• VA 20/40 OD and 20/20 OS

• Moderate bilateral optic atrophy

GVF

18 yo boy

• Playing around with friends

• Fell over backwards, hitting his occiput with loss of consciousness for one hour

• Blurred vision OU after that

• VA 20/400 OU

GVF

MRI

32 yo man

Afferent Diagnoses

• Compression

• Trauma

• Inflammation

• Ischemia

• Congenital and Genetic problems

Optic neuritis

Orbital pseudotumor

Other

27 yo woman

• Developed blurred vision OD and mild right periorbital pain

• VA 20/50

• MRI abnormal

• Diagnosis multiple sclerosis

Afferent Diagnoses

• Compression

• Trauma

• Inflammation

• Ischemia

• Congenital and genetic problems

Non-arteritic ischemic optic neuropathy

Central retinal artery occlusion

Other retinal emboli

Giant cell arteritis with ION

Giant Cell Arteritis, Day 2

Giant Cell Arteritis, Day 4

65 year old man

Afferent Diagnoses

• Compression

• Trauma

• Inflammation

• Ischemia

• Congenital and genetic problems

Congenital retinal dystrophies

Optic nerve hypoplasia

Leber hereditary optic neuropathy

Dominant and recessive optic atrophy

Glaucoma

70 yo man

Childhood Mild amblyopia OS

PMHSeizures well controlled with Phenobarbital

Family history Non-contributory

CC: Reduced vision OD for 3 days

Examination

OD OS

VA CF 1’ 20/40

Pupils 3+ APD

Anterior Mild NS Mild NS

Lids 8 mm 8mm

Fundi

Goldmann Visual Fields

IVFA

Evaluation

• ESR normal several times; VDRL and ANA normal• CT of head unremarkable• IVFA showed leakage at the right optic disk with

small hemorrhages temporally• DIAGNOSIS – NAION OD• Vision stable thereafter, until 5 months later …

when he c/o decreased vision OS x 2 days

Examination

OD OS

VA CF 3’ 20/50

Pupils 3+ APD

Color 0/10 4/10

GVF Unable Inf alt defect

Fundi

GVF

Clinical Course

• ESR normal again

• Treated with IV steroids without improvement

• DIAGNOSIS – sequential NAION

• Subsequently …

1 week later

Visual Acuity

OD OS

2 mo later CF 3’ CF 3’

4 mo later HM HM

2 yr later LP HM

3 yr later LP LP

Mitochondrial DNA Analysis

• Partial analysis of mitochondrial genome showed mutations at 4960 and 9957– 4960 mutation

• novel in our KSA analysis• affects a poorly conserved nucleotide in NADH

dehydrogenase subunit 2 (like secondary LHON mutations 4216 and 4917)

– 9957 mutation • reported previously in association with MELAS• note his history of seizures