Vision impairment impacts millions globally and varies from mild vision issues to total blindness. It is a medical condition where vision cannot be entirely corrected through glasses, contact lenses or surgery. This includes both low vision and complete blindness.
Medically, the term ‘vision impairment’ refers to reduced visual function that interferes with daily activities, including problems with sight acuity, contrast sensitivity or visual fields. Understanding blindness and low vision in detail can help with early detection, effective management and improved eye health. Read on to learn more about low vision and blindness.
Difference between Normal Vision and Impaired Vision
Normal vision allows clear detail, depth perception and peripheral awareness. Impaired vision however, limits clarity, sharpness or field of view, even after vision correction. Regular eye tests play a key role in detecting early visual impairment.
What is Low Vision?
Low vision is the term used to describe significant visual impairment that can’t be corrected fully with glasses, contact lenses, medication or eye surgery.
Symptoms of Low Vision
Symptoms of low vision vary from person to person. The most common types of vision loss associated with low vision include:
- Central vision loss: Central vision is the straight-ahead vision you use to see fine detail and the loss of this vision creates a blind or blurred spot directly in the line of sight. This condition severely hinders everyday tasks such as reading, driving and watching television.
- Peripheral vision loss: When you see things and movements outside the direct line of sight, it is your peripheral vision that you are using. Therefore, the loss of peripheral vision significantly affects everyday activities, making even simple tasks, such as driving or walking, challenging.
- Depth perception loss: Depth perception is your capacity to perceive objects in three dimensions, understanding their size and distance. The loss of depth perception reduces one’s ability to judge distances and the spacing between objects, making tasks like navigating stairs, packing or catching an object difficult to perform.
- Contrast sensitivity: Contrast sensitivity is the ability to tell the difference between two similar colours. It helps you recognise an object as being separate from the background behind it. When a patient has low contrast sensitivity, they have difficulty perceiving and distinguishing objects or patterns with subtle contrast differences.
- Night vision loss: Night vision loss, or night blindness, is when one has trouble seeing in dim or dark settings. This happens if your eyes have trouble quickly adjusting to changes in brightness or detecting light. Night vision loss results in blurry or cloudy vision in low light, increased light sensitivity, difficulty seeing distant objects and other vision issues.
Other symptoms could be:
- Difficulty reading, watching TV, or seeing people’s faces clearly
- Your eyes are uncomfortable in or sensitive to bright light
- Sudden change in vision
What is considered low vision or partially sighted?
To be certified as sight impaired (partially sighted), your sight must fall into one of the following categories, while wearing any glasses or contact lenses that you may need:
- Visual acuity of 3 / 60 to 6 / 60 with a full field of vision.
- Visual acuity ranges from 6/60 to 6/24, with a moderate reduction in the field of vision, cloudiness in parts of the eye, or if your lens has been removed without replacement by a lens implant.
- Visual acuity of 6 / 60 or above, but with a very reduced field of vision, especially if a lot of sight is missing in the lower part of the field.
What is blindness?
Simply put, blindness is a lack of vision. In the most severe cases, there’s an inability to see even light. It also means that you can’t correct your vision with eyeglasses, contact lenses, medical therapies or surgery.
Who is considered legally blind in the UK?
In the UK, an individual is legally deemed blind if they are unable to see beyond a certain point, even when using corrective lenses. The criteria consist of:
- Visual acuity of less than 3 / 60 with a full visual field.
- Visual acuity ranges from 3/60 to 6/60, accompanied by a severe reduction in the field of vision, such as tunnel vision.
- Visual acuity of 6/60 or above with
FAQs
1. Does low vision mean blindness?
No, low vision and blindness are two different conditions. Vision loss that cannot be corrected with glasses, contact lenses or surgery is known as low vision. However, because some vision remains, it is not classified as blindness. A person with low vision may have blurred vision, blind spots or poor night vision.
2. Can vision impairment worsen over time?
Yes, vision impairment often does worsen over time. It could happen either gradually or suddenly, depending on the underlying cause. While age-related changes are normal, conditions such as cataracts, glaucoma and macular degeneration can lead to progressive and sometimes permanent vision loss, if not managed appropriately.
3. Is vision impairment considered a disability in the UK?
Yes. Under the Equality Act 2010, individuals registered as blind, severely sight impaired, partially sighted or sight impaired by an ophthalmologist are automatically classified as disabled persons.
Disclaimer: The advice in this article is for informational purposes only and does not replace medical care or an in-person check-up. Please check with an eye care professional before purchasing any products or remedies. For information on our article review process, please refer to our Editorial Policy.
Khuram Sarwar is a qualified Dispensing Optician at Feel Good Contacts. He holds over 14 years of experience in the optical industry. Registered with the General Optical Council (GOC), Mr. Sarwar is also a member of the Association of British Dispensing Opticians (ABDO). He completed his training at ABDO College before achieving a BSc (Hons) in Ophthalmic Dispensing from Canterbury Christ Church University. In his professional career, Khuram has worked with some of the industry’s leading experts and continues to offer practical, expert advice on both contact lenses and glasses.
