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Article
September 1971

"RULE OF FOURS"

Author Affiliations

New Jersey College of Medicine and Dentistry 100 Bergen St Newark, NJ 07103

Arch Ophthalmol. 1971;86(3):360. doi:10.1001/archopht.1971.01000010362020

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Abstract

To the Editor.  —To facilitate remembering the amplitude of accommodation (AA) vs age in years, I have derived the following Rule of Fours for the benefit of your subscribers:

Ages 4 through 40:  (1) AA (diopters) =

Ages 41 through 49:  (2) AA (D) = 4 - 0.4(Age - 44)Rules of Fours 1 and 2 are of most practical value for ease of memory and application and are the best approximate mean values for the sake of simplicity.

Ages greater than 49 up to 59:  The preceding rules were derived by (3) AA (D) = 2 - 0.1(Age - 49) piecewise continuous linear analysis of Donders' data as modified by Duane1 for a lens which is placed before the emmetropic eye at a distance of 14 mm from the cornea (ie, the anterior focus of the eye as a reference point). Please note that age 4 and not age 8 was chosen as a starting

References
1.
Duane A:  Subnormal accommodation . Arch Ophthal 54:566-587, 1925.
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