Glossary
Eye care, like many of the medical sciences, is full of terms, jargon, and definitions. Here’s a ready-reckoner to key terms and definitions.
B
B Scan
A B scan is a non-invasive, 2D diagnostic imaging technique used in ophthalmology to visualize the internal structures of the eye. It is useful when the view inwards is obstructed by opaque media (like dense cataracts).
Blindness
The World Health Organization (WHO) defines blindness as vision less than 3/60 in the better eye, even with best possible correction. This is equivalent to being unable to count fingers at a distance of 3 meters (10 feet).
C
Cortical or cerebral visual impairment (CVI)
CVI is a condition where vision loss results from damage to the brain’s visual pathways, rather than the eyes themselves. It’s often caused by brain injury or damage, impacting how the brain processes visual information.
L
Low Vision
Low vision is a vision impairment that cannot be fully corrected with glasses, contact lenses, or surgery, making it difficult to perform everyday activities.
The World Health Organization (WHO) defines low vision as having a visual acuity of less than 6/18 (20/60) in the better eye with best possible correction, or a visual field of 20 degrees or less.