Amplitude of accommodation

Amplitude of accommodation (AA) is a measurement of the eye’s ability to focus clearly on objects at near distances (i.e. accommodation). This eye focusing range for a child is usually about 5–7.5 cm (2–3 inches). For a young adult, it is 10–15 cm (4–6 inches). The focus range for a 45-year-old adult is about 50 cm (20 inches). For an 80-year-old adult, it is 1.5 m (60 inches).

The average amplitude of accommodation, in diopters, for a patient of a given age may be estimated by Hofstetter's formula: 18.5 - (0.30 * patient age in years). The minimum amplitude of accommodation can likewise be estimated by: 15 - (0.25 * age in years), and the maximum amplitude of accommodation can be estimated by 25 - (0.40 * age in years)."

See also

• Convergence insufficiency
• Eye examination
• Negative relative accommodation
• Positive relative accommodation
• Presbyopia

External links

• http://www.ijo.in/article.asp?issn=0301-4738;year=2005;volume=53;issue=2;spage=105;epage=108;aulast=Abraham