Overview
Blindness and low vision are broad terms for vision loss that affects daily life. Vision loss may involve sharpness, side vision, central vision, color vision, or the ability to see in dim light. Some causes are present from birth, while others develop with aging, disease, infection, injury, or lack of access to eye care.
Key Symptoms
Symptoms can include blurred or cloudy vision, trouble reading, difficulty recognizing faces, poor night vision, loss of side vision, dark or blank spots, and sensitivity to light. Some people notice that colors look faded or that they need much brighter light to see. Sudden changes, eye pain, flashes of light, or a curtain-like shadow over vision need urgent evaluation.
Causes and Risk Factors
Vision loss can result from eye conditions such as cataract, glaucoma, diabetic retinopathy, age-related macular degeneration, corneal disease, retinal detachment, and inherited eye disorders. It can also happen after stroke, infections, injuries, vitamin A deficiency, or complications of premature birth. Risk may be higher with older age, diabetes, high blood pressure, smoking, family history, certain medicines, and limited access to eye services.
Who Is Affected
Blindness and low vision can affect people of any age, including babies and children. Older adults are more likely to develop age-related eye diseases, while people with diabetes are at higher risk for diabetic eye damage. In many parts of the world, poverty, malnutrition, untreated infections, and barriers to care increase the burden of avoidable vision loss.
Prevention
Some vision loss can be reduced by regular eye exams, managing long-term conditions such as diabetes and high blood pressure, protecting the eyes from injury, and avoiding smoking. Vaccination, infection control, good prenatal and child health care, and timely treatment of eye problems also matter in some settings. Children should have vision checks, and adults should follow local guidance on routine eye care.
Diagnosis and Tests
Assessment usually starts with questions about symptoms, medical history, medicines, and daily difficulties. Eye professionals may check visual acuity, side vision, eye pressure, pupil response, and the front and back of the eye. Some people also need imaging, retinal photographs, blood sugar testing, or referral to a specialist depending on the suspected cause.
Treatment Categories
Treatment depends on the cause and may include glasses or contact lenses, surgery such as cataract surgery, laser treatment, medicines given by an eye specialist, or treatment of related health conditions. Not all vision loss can be reversed, but care may slow worsening or improve function. Low vision rehabilitation can help with magnifiers, lighting changes, orientation and mobility training, and other assistive tools.
Living With It
People with low vision or blindness can often improve independence with rehabilitation, assistive technology, home adjustments, and support from family, school, work, and community services. Useful changes may include high-contrast labels, brighter lighting, large-print or audio materials, screen readers, and mobility aids. Emotional support is also important because vision loss can affect confidence, work, and social connection.
When to Seek Medical Care
Arrange medical care if vision is gradually worsening, if daily activities become harder, or if you notice problems such as glare, halos, eye strain, or trouble seeing at night. People with diabetes, high blood pressure, eye injuries, or a family history of serious eye disease should keep regular follow-up appointments. Children should be checked if they squint, sit very close to screens, have wandering eyes, or seem not to see normally.
When It May Be an Emergency
Get urgent medical help right away for sudden vision loss in one or both eyes, severe eye pain, sudden double vision, new flashes and many floaters, a curtain or shadow over vision, chemical exposure, or an eye injury. These symptoms can be caused by conditions that threaten sight and sometimes general health, such as retinal detachment, stroke, acute glaucoma, or serious infection.