Unit 2: Visual field defects, double vision & optic disc swelling

Monocular Diplopia

Double vision which persists when one eye is covered.

Usually described as 'Ghosting'.

Causes

• Corneal abnormalities e.g. Scarring
• Uncorrected refractive error.
• Cataract.

Unequal refractive error across the lens causes uneven splitting of light.

Binocular Diplopia

This occurs when the two eyes become misaligned in the straight ahead position or in various positions of gaze. Diplopia may be due to the motor nerves or the extra ocular muscles but needs thorough investigation (see below):

• Visual Acuity
• Observe an abnormal head posture (AHP)
• Refraction
• Eye movements (ocular motility)
• Cover test