- Low vision is a general term describing visual impairment that requires patients to use devices and strategies in addition to corrective lenses to perform visual tasks.
- Low vision is defined as a best corrected visual acuity (BCVA) of 20/70 to 20/200
- Impaired vision is accompanied by difficulty in performing functional activities.
- Individuals with visual acuity of 20/80 to 20/100 with a visual field restriction of 60 degrees to greater than 20 degrees can read at a nearly normal level with optical aids.
- Their visual orientation is near normal but requires increased scanning of the environment (ie, systematic use of head and eye movements).
- In a visual acuity range of 20/200 to 20/400 with a 20-degree to greater than 10 degree visual field restriction, the individual can read slowly with optical aids. His or her visual orientation is slow, with constant scanning of the environment; individuals in this category have vision.
- Blindness is defined as a BCVA of 20/400 to no light perception. The clinical definition of absolute blindness is the absence of light perception.
- Patients with a visual field radius no greater than 1 0 degrees but greater than 5 degrees around central fixation should be placed in category 3, and patients with a field no greater than 5 degrees around central fixation in category 4- even if the central acuity is not impaired.
- Cataract (62.6%)
- Posterior Capsular Opacification (0.90%)
- Refractive Error (19.70%)
- Corneal Blindness (0.90%)
- Posterior Segment Disorder(4.70%),
- Glaucoma (5.80%)
- Surgical Complication (l .20%)
- Others (4.19%)
- Reading and magnification
- Magnifying glasses
- Talking books, Readers or reading machines, which convert printed text to speech or Braille.
- Computers with special hardware such as scanners and refreshable Braille displays as well as software written specifically for the blind, such as optical character recognition applications and screen readers.
- Mobility-Tools such as the white cane with a red tip - the international symbol of blindness
- Lighter identification (ID) cane
- Guide dogs