Optic Atrophy


Aetiology in Children
- Hydrocephalus
- Hereditary (dominant, recessive, or x-linked)
- Space occupying lesions (intracranial, orbital)
- Heavy metal poisoning (lead, arsenic)
- Secondary to papilloedema
- Cerebral Degenerations

Clinical Findings
- Diminished vision
- Pupil reaction to light reduced
- Marcus Gunn Pupil – (consensual reaction greater than direct)
- Pallor of optic disc and reduced vessels on disc.
- Visual field changes
- Abnormal visual evoked potential
- (of particular value to children too young to measure vision or to perform visual fields.)
- C.T. Scan is necessary

Note: Optic Atrophy requires a full neurological investigation

Papilloedema

Definition
– swelling and vascular congestion of the optic disc – with blurring of disc margins, haemorrhages and venous dilatation.

Aetiology
- Hypertension – always associated with severe hypertensive retinopathy
- Raised intracranial pressure – vision will be normal and visual fields show only enlargement of the blind spot in the early stages.

 Differential Diagnosis
- Papillitis – an identical appearance of the optic disc.  But vision is profoundly disturbed – (central scotoma)
-Toxic optic neuropathy
- Demyelination
- Pseudopapilloedema – blurred disc margins due to hypermetropia. No venous congestion.

A congested swollen disc without raised intracranial pressure, also occurs with chronic cyanotic cardiac and pulmonary disease due to carbon dioxide retention.

Management of Papilloedema

Full neurological examination and investigation is required to exclude possible causes of raised intracranial pressure.

eg        
– Space occupying lesions
- Infective causes
- Benign intracranial hypertension

If papilloedema is not relieved permanent loss of vision and constriction of fields (with optic atrophy) may result.


Abnormal Pupillary Reactions

Anisocoria
– ( unequal pupils) is present in about 20% of the normal population

Pathological Anisocoria
- Large pupil – 3rd nerve paresis – associated with muscle palsies
- Small pupil – sympathetic paralysis (Horner’s Syndrome)
- Mydriasis may also occur because of eye drops, some plants and trauma.
- Horner’s Syndrome – Miosis, Ptosis, Enophthalmos, anhydrosis

If this occurs before two years of age Heterochromia of the Iris results.

Congenital Horner’s commonly occurs due to birth trauma but occasionally may be due to a mediastinal tumour (eg neuroblastoma.)