Visual acuity is a mainstay for the assessment of “How the EYE functions”. Traditional, non-logarithmic, visual acuity charts, however, are inaccurate for visual acuities worse than 20/100. Dr. Colenbrander developed a logarithmic Low Vision letter chart for use at 1 meter, which extends accurate measurement to 1/50 (20/1000). With it, he developed guidelines for a systematic Low Vision evaluation.
The Basic Low Vision Exam. PDF
The Historical Evolution of Visual Acuity Measurement. August Colenbrander. Visual Impairment Research 10(2,3):57-66 (2008). PDF
