Amplitude of accommodation
The amplitude of accommodation is the maximum increase in optical power that an eye can achieve in adjusting its focus from as far as possible (beyond infinity for a longsighted eye) to the nearest possible. It confers a certain range of object distances for which the retinal image is as sharply focussed as possible.
Amplitude of accommodation is measured during routine eye-examination. The closest that a normal eye can focus is typically about 10 cm for a child or young adult. Accommodation then decreases gradually with age, effectively finishing just after age fifty.
The average amplitude of accommodation, in diopters, for a patient of a given age was estimated by Hofstetter in 1950 to be 18.5 - (0.30 * patient age in years) with the minimum amplitude of accommodation as 15 - (0.25 * age in years), and the maximum as 25 - (0.40 * age in years). However, Hofstetter's work was based on data from two early surveys which, although widely cited, used methodology with considerable inherent error.
- Convergence insufficiency
- Eye examination
- Negative relative accommodation
- Positive relative accommodation
- Anderson H, Hentz G, Glasser A, Stuebing K, Manny R. Minus-Lens–Stimulated Accommodative Amplitude Decreases Sigmoidally with Age: A Study of Objectively Measured Accommodative Amplitudes from Age 3. Invest Ophthalmol Vis Sci 2008; 49; 2919-2926.
- Atchison D, Capper E, McCabe, K. Critical subjective measurement of amplitude of accommodation. Optom Vis Sci 1994; 71: 699-706
- Hamasaki D, Ong J, Marg E. The amplitude of accommodation in presbyopia. Am J Optom 1956; 33: 3-14.
- Duane A. Studies in monocular and binocular accommodation with their clinical applications. Trans Am Ophthalmol Soc 1922; 20: 132-157
- Donders F. On the anomalies of the accommodation and refraction of the eye. (W. Moore Trans.) UK: The New Sydenham Society, 1864. p 207-209.