Editing Visual acuity (section)

=== Legal definitions ===
Various countries have defined statutory limits for poor visual acuity that qualifies as a disability. For example, in Australia, the Social Security Act defines blindness as:

{{blockquote|text=A person meets the criteria for permanent blindness under section 95 of the Social Security Act if the corrected visual acuity is less than 6/60 on the Snellen Scale in both eyes or there is a combination of visual defects resulting in the same degree of permanent visual loss.<ref>''Social Security Act'' 1991 (Cth) {{Cite web |title=Table 13, Schedule 1B |url=https://www.legislation.gov.au/Details/C2011C00765/Html/Volume_3#_Toc304376657}} as at 20 September 2011.</ref>}}

In the US, the relevant federal statute defines blindness as follows:<ref>42 U.S.C. §&nbsp;416(i)(1)(B) (Supp. IV 1986). Cited in {{Cite web |date=9 November 1990 |title=SSR 90-5c: Sections 216(i)(1)(B) and 223(c)(1) and (d)(1)(B) of the Social Security Act (42 U.S.C. 416(i)(1)(B) and 423(c)(1) and (d)(1)(B)) Disability insurance benefits – Interpreting the statutory blindness provision |url=https://www.law.cornell.edu/socsec/rulings/ssr/SSR90-05.html}}</ref>

{{blockquote|text=[T]he term "blindness" means central visual acuity of 20/200 or less in the better eye with the use of a correcting lens. An eye that is accompanied by a limitation in the fields of vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees shall be considered for purposes in this paragraph as having a central visual acuity of 20/200 or less.}}

A person's visual acuity is registered documenting the following: whether the test was for distant or near vision, the eye(s) evaluated and whether [[corrective lenses]] (i.e. [[glasses]] or [[contact lens]]es) were used:
* Distance from the chart
** D (distant) for the evaluation done at {{convert|20|ft|m|sigfig=1}}.
** N (near) for the evaluation done at {{convert|15.7|in}}.
* Eye evaluated
** OD (Latin ''oculus dexter'') for the right eye.
** OS (Latin ''oculus sinister'') for the left eye.
** OU (Latin ''oculi uterque'') for both eyes.
* Usage of spectacles during the test
** cc (Latin ''cum correctore'') with correctors.
** sc: (Latin ''sine correctore'') without correctors.
* [[Pinhole occluder]]
** The abbreviation PH is followed by the visual acuity as measured with a pinhole occluder, which temporarily corrects for [[refractive error]]s such as myopia or astigmatism.
** PHNI means no improvement of visual acuity using a pinhole occluder.
So, distant visual acuity of 6/10 and 6/8 with pinhole in the right eye will be: DscOD 6/10 PH 6/8. Distant visual acuity of count fingers and 6/17 with pinhole in the left eye will be: DscOS CF PH 6/17. Near visual acuity of 6/8 with pinhole remaining at 6/8 in both eyes with spectacles will be: NccOU 6/8 PH 6/8.

"Dynamic visual acuity" defines the ability of the eye to visually discern fine detail in a moving object.