Low vision is when your vision impaired and cannot be further improved with the help of traditional form of treatments like spectacles, contact lenses, medication and surgical intervention. Low vision always reduces or restricts your functional vision (the ability to use your vision to carry out your day-to-day activities). So, to be simple Low vision is when you have reduced vision than normal but not blind. You can be best helped with low vision devices like large prints, magnifiers, and illumination.
Junior optometrist/ ophthalmologist often asks “which patients should be referred to a low vision service? or “is there a level of visual acuity below which patients should be referred?“.
I would every-time say ‘Yes’ to them, To call somebody low vision patient he should meet the criteria. he should have reduced functional vision ie he should have difficulties in the day-to-day.
Now you would ask me what is the criteria for low vision. Whom should be called low vision patients.
WHO standard definition
“Low vision are those who suffer visual acuity between 20/200 to 70/200 (Snellen) or 6/18 to 6/60 in the better eye after the best possible correction or a field of vision between 20 to 30 degrees”.
WHO working definition
“A person with low vision is one who has impairment of visual functioning even after treatment, and/ or standard refractive correction, and has a visual acuity of less than 6/18 to light perception or a the visual field of less than 10 degrees from the point of fixation, but who uses, or is potentially able to use, vision for the planning and/or execution of a task”.
Low vision versus Legally blindness
In India, Blindness as defined by National Programme for Control of Blindness (NPCB) 1)Npcb.nic.in. (2018). National Programme for Control of Blindness, Ministry of Health & Family Welfare, Government of India. [online] Available at: http://npcb.nic.in/index1.asp?linkid=55 [Accessed 29 Apr. 2018]. under following headings:
- Visually acuity less than 3/60(20/400) in the better eye
- Limitation of the field of vision less than 10 degrees from the centre of fixation.
Several studies indicate total blindness is relatively rare and that the majority of visually impaired people have low vision. Low vision is, however, very poorly recognized, and even more rarely understood, by the community.
Check out What causes of Low Vision in India.
References [ + ]
|1.||↑||Npcb.nic.in. (2018). National Programme for Control of Blindness, Ministry of Health & Family Welfare, Government of India. [online] Available at: http://npcb.nic.in/index1.asp?linkid=55 [Accessed 29 Apr. 2018].|