The majority of people with vision impairment and blindness are over the age of 50 years; however, vision loss can affect people of all ages. In 2020, the leading global causes of blindness in those aged ≥50 years were cataract, followed by glaucoma, undercorrected refractive error, age-related macular degeneration, and diabetic retinopathy.
Vision loss may occur from an abnormality at any point in the visual pathway from the tear film to the occipital cortex. The most important factor to determine initially is the rapidity of symptom onset. Early assessment of the presence or absence of associated symptoms such as pain, double vision, and flashes and/or floaters is also important. This helps to identify patients with potentially life-threatening disease, and highlights those requiring prompt ophthalmology evaluation or surgical intervention.
Acute vision loss that occurs suddenly or over the course of several minutes to hours usually requires urgent ophthalmic consultation. People with sub-acute or chronic vision loss (where vision loss has developed over weeks, months, or years) may still need specialist input, but usually on a non-urgent basis.
Any significant vision loss justifies a call to an ophthalmologist for advice on referral timing.
Vision loss may also be the initial manifestation of a number of systemic diseases for which separate work-up is required.
Acute vision loss
Retinal or optic nerve disease may present acutely. Other acute causes of vision loss include acute angle-closure glaucoma, retinal vascular occlusion, and trauma. Retrospective data suggest that, in the UK, the largest proportion of patients accessing emergency eye services are aged 50-90 years, possibly because of increased risk for ocular emergencies including vitreoretinal, retinal vascular, and macular disorders. Patients attending emergency departments with ocular trauma are younger.
The patient's age and determination of the medical history assists in diagnosis.
Chronic vision loss
Patients may recognise symptoms of chronic vision loss 'acutely', meaning chronic vision loss may present in the accident and emergency department, making diagnosis difficult.
Associated symptom review makes it possible to differentiate between urgent and non-urgent cases and arrange for appropriate ophthalmic consultation.
It is essential to take thorough histories, focusing on vascular and neurological processes, as well as visual processes.
Diabetic retinopathies may develop before systemic diabetes is diagnosed, making it important to measure blood glucose levels in all patients presenting with acute vision loss. Arrange an ophthalmological examination for all newly diagnosed adults with diabetes.
Other serious systemic diseases (including granulomatosis with polyangiitis, bacterial meningitis, or disseminated malignancies) may need to be addressed in the emergency department or by hospital admission.
- Corneal ulcer
- Dry eye syndrome (tear dysfunction syndrome)
- Dry age-related macular degeneration
- Posterior uveitis
- Non-diabetic myopic lens shift
- Wet age-related macular degeneration
- Vitreous haemorrhage
- Retinal venous occlusion
- Retinal arterial occlusion
- Migraine headache or migraine aura without headache (acephalgic migraine)
- Pituitary tumour
- Diabetic retinopathy
- Diabetic myopic lens shift
- Corneal hydrops
- Traumatic vision loss
- Optic neuritis
- Leber's hereditary optic neuropathy (LHON)
- Acute angle-closure glaucoma
- Retinal detachment
- Post-operative endophthalmitis
- Central retinal artery occlusion
- Pituitary apoplexy
- Arteritic anterior ischaemic optic neuropathy/giant cell arteritis
- Non-arteritic anterior ischaemic optic neuropathy
- Transient ischaemic attack (TIA)
- Cancer-associated retinopathy
- Clinical guidelines: retinal vein occlusion
- Glaucoma: diagnosis and management
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