Assessment of vision loss

Globally, at least 2.2 billion people have a near or distance vision impairment.[1]World Health Organization. Blindness and vision impairment. Oct 2022 [internet publication]. https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment  In almost half of these cases, the visual impairment may have been preventable or remains untreated.[1]World Health Organization. Blindness and vision impairment. Oct 2022 [internet publication]. https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment

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.[1]World Health Organization. Blindness and vision impairment. Oct 2022 [internet publication]. https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment  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.[2]GBD 2019 Blindness and Vision Impairment Collaborators; Vision Loss Expert Group of the Global Burden of Disease Study. Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study. Lancet Glob Health. 2021 Feb;9(2):e144-60 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820391 http://www.ncbi.nlm.nih.gov/pubmed/33275949?tool=bestpractice.com

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.[3]Rossi T, Boccassini B, Iossa M, et al. Triaging and coding ophthalmic emergency: the Rome Eye Scoring System for Urgency and Emergency (RESCUE): a pilot study of 1,000 eye-dedicated emergency room patients. Eur J Ophthalmol. 2007 May-Jun;17(3):413-7. http://www.ncbi.nlm.nih.gov/pubmed/17534826?tool=bestpractice.com [4]Ramos M, Kruger EF, Lashkari K. Biostatistical analysis of pseudophakic and aphakic retinal detachments. Semin Ophthalmol. 2002 Sep-Dec;17(3-4):206-13. http://www.ncbi.nlm.nih.gov/pubmed/12759852?tool=bestpractice.com

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.[5]Klig JE. Ophthalmologic complications of systemic disease. Emerg Med Clin North Am. 2008 Feb;26(1):217-31. http://www.ncbi.nlm.nih.gov/pubmed/18249264?tool=bestpractice.com

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.[6]De Silva I, Thomas MG, Shirodkar AL, et al; BEECS Study Group, Buchan J, Verma S. Patterns of attendances to the hospital emergency eye care service: a multicentre study in England. Eye (Lond). 2021 Nov 30:1-8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8629695 http://www.ncbi.nlm.nih.gov/pubmed/34845355?tool=bestpractice.com Patients attending emergency departments with ocular trauma are younger.[7]Fea A, Bosone A, Rolle T, et al. Eye injuries in an Italian urban population: report of 10,620 cases admitted to an eye emergency department in Torino. Graefes Arch Clin Exp Ophthalmol. 2008 Feb;246(2):175-9. http://www.ncbi.nlm.nih.gov/pubmed/18183412?tool=bestpractice.com [8]Galindo-Ferreiro A, Sanchez-Tocino H, Varela-Conde Y, et al. Ocular emergencies presenting to an emergency department in Central Spain from 2013 to 2018. Eur J Ophthalmol. 2021 Mar;31(2):748-53. http://www.ncbi.nlm.nih.gov/pubmed/31865769?tool=bestpractice.com

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.

Systemic considerations

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.[9]Jones HL, Walker EA, Schechter CB, et al. Vision is precious: a successful behavioral intervention to increase the rate of screening for diabetic retinopathy for inner-city adults. Diabetes Educ. 2010 Jan-Feb;36(1):118-26. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4582664 http://www.ncbi.nlm.nih.gov/pubmed/20044537?tool=bestpractice.com [10]Solomon SD, Chew E, Duh EJ, et al. Diabetic retinopathy: a position statement by the American Diabetes Association. Diabetes Care. 2017 Mar;40(3):412-8. https://www.doi.org/10.2337/dc16-2641 http://www.ncbi.nlm.nih.gov/pubmed/28223445?tool=bestpractice.com

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.[11]Mitra A, Chavan R, Gunda M. Occult giant cell arteritis and steroid therapy: how urgent is urgent? Ann Ophthalmol (Skokie). 2006 Winter;38(4):343-5. http://www.ncbi.nlm.nih.gov/pubmed/17726223?tool=bestpractice.com