[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Ophthalmology](https://durgical.com/en/ophthalmology/) › [Referral and eye health in Colombia](https://durgical.com/en/ophthalmology/areas/referral/) › Avoidable blindness: the main causes in the world and in Colombia # Avoidable blindness: the main causes in the world and in Colombia - Topic Most visual impairment in the world could be prevented or treated: glasses and cataract surgery alone would restore sight to many millions. Updated Nov 5, 2026 **See it in 3D:** [Lens](https://durgical.com/en/anatomy/lens/) · [Retina](https://durgical.com/en/anatomy/retina/) · [Cornea](https://durgical.com/en/anatomy/cornea/) ## Key points - ≥ 2.2 billion with vision impairment; ≥ 1 billion avoidable or unaddressed. - Top cause of impairment: uncorrected refractive error. - Top cause of blindness: cataract. - Colombia: first country free of onchocerciasis transmission. ## What it is The World Health Organization estimates that at least 2.2 billion people live with a near or distance vision impairment, and in at least 1 billion of them it could have been prevented or has not yet been addressed. The leading causes are uncorrected refractive error and cataract, both treatable with low-cost interventions. Glaucoma, diabetic retinopathy, macular degeneration, corneal opacity and trachoma follow. Access, cost and awareness, not lack of treatments, keep people blind. ## Key facts - Leading cause of vision impairment worldwide: uncorrected refractive error. - Leading cause of blindness worldwide: cataract. - Other causes: glaucoma, diabetic retinopathy, age-related macular degeneration, corneal opacity, trachoma. - Children: refractive error, amblyopia, congenital cataract, retinopathy of prematurity, vitamin A deficiency. - Colombia was the first country certified by WHO as free of onchocerciasis transmission. ## In clinical practice - The general doctor prevents blindness by screening (red reflex, acuity, diabetic retina, glaucoma suspicion) and by completing referrals. - Diabetes and population ageing are increasing the burden of retinal disease and glaucoma. - WHO promotes integrated, people-centred eye care within primary health care. ## Next step / Initial management - Check visual acuity at every health check where it is due and refer by criteria. - Make sure people with cataract that limits daily life reach surgery. - Screen diabetic patients' retinas and children's eyes on schedule. - Prescribe and help obtain glasses: the cheapest effective eye intervention. ## Test yourself Think of the answer, then tap the question to see it. ## What is the leading cause of blindness worldwide? Cataract. ## What is the leading cause of vision impairment worldwide? Uncorrected refractive error. ## Which eye-related public health milestone did Colombia reach first? It was the first country certified by WHO as having eliminated onchocerciasis transmission. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/ophthalmology/avoidable-blindness-the-main-causes-in-the-world-and-in-colombia/) ## Connections ## See it in 3D 3 The structures of Durgical's 3D anatomy where it is found. - [Lens](https://durgical.com/en/anatomy/lens/) - [Retina](https://durgical.com/en/anatomy/retina/) - [Cornea](https://durgical.com/en/anatomy/cornea/) ## Related 4 - [Visual impairment and blindness: how they are graded](https://durgical.com/en/ophthalmology/visual-impairment-and-blindness-how-they-are-graded/) - [Visual screening in Colombia: what the RIAS ask for](https://durgical.com/en/ophthalmology/visual-screening-in-colombia-what-the-rias-ask-for/) - [Low vision and visual rehabilitation](https://durgical.com/en/ophthalmology/low-vision-and-visual-rehabilitation/) - [Refraction: dioptres and reading a prescription](https://durgical.com/en/ophthalmology/refraction-dioptres-and-reading-a-prescription/) ## Related conditions 7 - [Cataract](https://durgical.com/en/conditions/cataract/) - [Refractive errors and presbyopia](https://durgical.com/en/conditions/refractive-errors-and-presbyopia/) - [Open-angle glaucoma](https://durgical.com/en/conditions/open-angle-glaucoma/) - [Diabetic retinopathy](https://durgical.com/en/conditions/diabetic-retinopathy/) - [Trachoma](https://durgical.com/en/conditions/trachoma/) - [Onchocerciasis (river blindness)](https://durgical.com/en/conditions/onchocerciasis/) - [Vitamin A deficiency (night blindness and xerophthalmia)](https://durgical.com/en/conditions/vitamin-a-deficiency/) [← All of ophthalmology](https://durgical.com/en/ophthalmology/) Educational content; not a clinical guideline and no substitute for assessment by a health professional. For sudden visual loss, severe eye pain, a chemical burn or an eye injury, go to an emergency department at once. Sources: [World report on vision](https://www.who.int/publications/i/item/9789241516570) (World Health Organization, 2019); [Blindness and vision impairment: fact sheet](https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment) (World Health Organization, 2023); [Onchocerciasis: fact sheet](https://www.who.int/news-room/fact-sheets/detail/onchocerciasis) (World Health Organization, 2022). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/ophthalmology/avoidable-blindness-the-main-causes-in-the-world-and-in-colombia/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/ophthalmology/avoidable-blindness-the-main-causes-in-the-world-and-in-colombia/