Low Vision Assessment — Complete User Guide

Definition of Low Vision

Low vision refers to significant vision impairment that cannot be fully corrected with conventional spectacles, contact lenses, or medical/surgical treatment. According to WHO:

• Visually impaired: Best corrected visual acuity <20/400 (0.05) in better eye, or visual field <10° from fixation point
• Blind: Best corrected visual acuity <20/1200 (0.0167) in better eye, or visual field <5°

Low Vision Acuity Notation

Counting Fingers (CF)

Used when visual acuity is too low to count fingers: CF at 1m, 2m, etc.

Hand Motions (HM)

Used when patient can perceive hand movement but cannot count fingers.

Light Perception (LP) / No Light Perception (NLP)

Extreme low vision; LP: can perceive light, NLP: cannot perceive any light.

Magnification Requirement

Required magnification = Near acuity goal / Current near acuity

Example: If current acuity is 0.1 and goal is 0.5, required magnification = 0.5/0.1 = 5×

References

• WHO. International Classification of Diseases 11. 2018.
• American Academy of Ophthalmology. Low Vision and Vision Rehabilitation. 2023.