13th December 2023

Assessment of vision loss

Vision loss may occur from an abnormality anywhere in the visual system, from the tear film to the occipital cortex. Initial evaluation should focus on determining the onset and severity of vision loss, associated systemic symptoms, and monocular or binocular involvement. It is important to recognise that patients with homonymous visual field defects may perceive their vision loss as monocular.

Any significant vision loss should be discussed with the local ophthalmology team following initial assessment.

Onset

• Acute vision loss over minutes to hours requires urgent ophthalmic opinion.
• Common causes of acute vision loss include acute angle-closure glaucoma, retinal vascular occlusion, ischaemic optic neuropathy and trauma.
• Sub-acute or chronic vision loss (weeks to months) should also be discussed to arrange formal ophthalmic assessment.

Associated symptoms

• Flashes, floaters and trauma increase the likelihood of retinal detachment.
• Painful eye movements in younger patients may indicate optic neuritis.
• Headaches may be a feature of giant cell arteritis, raised intracranial pressure or migraine.

Past medical history

• Diabetes and hypertension are associated with ocular vascular disease.
• Diabetes and corticosteroid use are associated with accelerated cataract formation.

Ophthalmic history

• It is important to ask about glasses and contact lens use.
• Myopia (short-sightedness) is associated with increased risk of retinal detachment.
• Hypermetropia (long-sightedness) is a risk factor for acute angle closure glaucoma.
• A red eye in a contact lens wearer requires careful ophthalmic examination.
• Previous ocular surgery and its temporal relation to visual loss should be enquired about.

Medication history

• Digoxin is associated with yellowing of vision.
• Phosphodiesterase type-5 (PDE-5) inhibitors (sildenafil, tadalafil, vardenafil) may cause transient blue tints.
• The use of PDE-5 inhibitors has been associated with an increased risk of non-arteritic anterior ischaemic optic neuropathy.
• Amiodarone may cause progressive optic neuropathy.
• Tetracyclines and vitamin A derivatives are associated with raised intracranial pressure.

Source: Denniston, A., & Murray, P. (2018). Oxford Handbook of Ophthalmology (4th ed.) Oxford University Press