Changes in vision — whether sudden or gradual — should never be ignored. From benign refractive errors to retinal detachment and stroke, vision changes span a wide spectrum of urgency.
Changes in vision encompass a broad range of symptoms: blurred vision (near, distance, or both), double vision (diplopia), floaters, flashes of light, visual field loss, colour changes, and complete or partial vision loss. In Korea, residents have access to world-class eye care, with Seoul home to some of the highest concentrations of refractive surgery and ophthalmology centres in the world, alongside major hospitals' ophthalmology departments and Seoul National University Children's Hospital for paediatric eye care.
Sudden vision changes require urgent or emergency assessment. Painless sudden vision loss may indicate central retinal artery occlusion (a 'stroke of the eye') — a medical emergency requiring treatment within hours. Retinal detachment presents as a curtain across the vision, floaters, or flashes — and requires same-day surgical repair. Giant cell arteritis (temporal arteritis) in older adults causes sudden vision loss with headache and jaw pain — urgent corticosteroid treatment can prevent blindness in the other eye.
Gradual vision changes are often less urgent but still important. Diabetic retinopathy — damage to retinal blood vessels from poorly controlled diabetes — is a leading cause of preventable blindness globally, and Korea's national diabetes management programmes include recommended annual retinal screening. Glaucoma causes gradual peripheral vision loss without pain — screening is essential for those with a family history or raised intraocular pressure. Cataracts cause progressive clouding and are highly correctable with surgery available at Korea's ophthalmology centres.
Key Points
- Sudden painless vision loss — eye emergency, call 119 or go to hospital
- Retinal detachment (flashes, floaters, curtain) — same-day surgery needed
- Diabetic retinopathy — annual retinal screening for all diabetics
- Glaucoma — silent peripheral vision loss — screen if family history
- Seoul has world-renowned ophthalmic care and refractive surgery centres
- Gradual blurring — most commonly refractive error or cataracts
Causes & Risk Factors
- Refractive errors — myopia, hyperopia, astigmatism (most common)
- Diabetic retinopathy — retinal damage from high blood glucose
- Glaucoma — raised intraocular pressure damaging optic nerve
- Cataracts — lens clouding causing progressive blurring
- Retinal detachment — emergency, risk factors include trauma and myopia
- Stroke — visual field loss from brain's visual cortex damage
When to See a Doctor
- Sudden vision loss in one or both eyes — emergency (call 119)
- Sudden onset of floaters, flashes, or curtain/shadow in vision
- Double vision (diplopia) — especially new onset
- Eye pain with vision change — possible acute glaucoma
- Any diabetic with no recent eye examination
For emergencies in Korea, call 119
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This content is published for educational purposes only. For accurate diagnosis and personalised treatment, consult a licensed KMA physician in Korea.
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Medical Disclaimer
This article is published by DoctorsInKorea.com for educational and informational purposes only. It does not replace a professional clinical evaluation by a licensed healthcare provider. For accurate medical diagnosis and personalised treatment paths, please book an appointment with a licensed KMA physician. For immediate life-threatening medical emergencies in Korea, please call 119.
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Last reviewed: March 1, 2025