INSTRUCTION

Examine this patient's eyes.

Examine this patient's visual fields.

SALIENT FEATURES

History

See optic atrophy (pp 529-31), retinitis pigmentosa (pp 535-7).

Examination

Intact central vision with constriction of the peripheral fields.

Proceed as follows:

Examine for the following:

· Optic atrophy (primary and secondary).

· Retinitis pigmentosa (see pp 535-7).

· Choroidoretinitis (see p. 538).

· Glaucoma.

DIAGNOSIS

This patient has tunnel vision (lesion) due to retinitis pigmentosa (aetiology).

ADVANCED-LEVEL QUESTIONS

What are the other causes of tunnel vision?

· Hysteria.

· Slight contraction of field occurs when there is a significant refractive error.

Note. Before making a diagnosis of hysteria, it is essential to exclude contraction of the visual fields due to extreme fatigue, poor

attention, inadequate vision, diminished visual acuity or delayed reaction time.

How would you differentiate hysteria from an organic cause of tubular vision?

In organic causes the field of vision widens progressively as the test objects are held further away from the eye, but in the hysterical

person this widening is not seen and the entire width of the field is as great at 1 foot from the eye as it is at 5, 10 or 15 feet.