Amplitude Of Accommodation Inspection

Accommodation: the process in which the human eye changes the curvature of the lens to increase the refractive power of the eye so that close objects can still be clearly imaged on the retina, which is called eye accommodation.

Before Accommodation 

After Accommodation 

Amplitude of accommodation (AMP): the maximum accommodation force that the human eye can produce is called accommodation amplitude, which is the difference between the refractive power when looking at the far point and the near point.

Inspection Method

1.Push-Up
2.Minus Lens
3.Hostetter
4.Donder

3.Hostetter

It is a formula designed by Hofstetter to calculate the relationship between age and accommodation amplitude after a large number of clinical trials and statistics in the 1950s:

Minimum accommodation amplitude = 15-0.25 * age
Mean accommodation amplitude = 18.5-0.3 * age

4.Donder

The accommodation amplitude gradually decreases with the increase of age. You can use the Donder table to estimate a person's accommodation amplitude, or use the accommodation amplitude obtained by querying the table to judge the measurement results and measure the accommodation ability.

Donder

Note:
1. In the push-up method, the distance between the near vision card and the main point of the eye is the visual scale distance plus 1.35 mm behind the cornea, which can be ignored because the distance behind the cornea is too small.
2. During the push-up method, the vision chart will be enlarged due to the approach of near vision card, so the result is about 2D higher than that of minus lens method.
3. The refractive state will affect the measurement of accommodation amplitude.
4. The size of the vision chart also affects the value of the accommodation amplitude.