What is accommodation amplitude?

Amplitude of accommodation (AA) is the maximum amount of accommodative power, in diopters, that the eye can exert. It represents the difference between the far point and near point of the eye.

What is the push-up method?

The push-up method measures the near point of accommodation — the closest distance at which the patient can clearly see a target. AA is calculated as 100 divided by that distance in centimeters (converting cm to diopters: D = 100/cm).

What is the minus lens method?

With the minus lens method the patient views a target at a fixed working distance while increasing minus lenses are added until blur occurs. AA equals the dioptric equivalent of the working distance plus the total minus lens power added.

What are Hofstetter's norms?

Hofstetter (1950) derived age-based formulas: Maximum AA = 25 − 0.4 × age; Expected AA = 18.5 − 0.3 × age; Minimum AA = 15 − 0.25 × age. Results below the minimum norm may indicate accommodative insufficiency.

Amplitude of accommodation is expressed in diopters (D), which equals 1 / distance in meters. A near point of 10 cm (0.10 m) equals 10 D of accommodation.

Is this tool a diagnostic instrument?

No. This calculator is for reference and educational purposes only. Clinical decisions should be made by a licensed optometrist or ophthalmologist using calibrated instrumentation.

Accommodation Amplitude

Calculate the amplitude of accommodation in diopters from near point distance measurements.

Measurement Input

Method

Push-Up Minus Lens

Near Point Distance (cm)

Closest distance at which the patient sees clearly.

Patient Age (optional — for Hofstetter norms)

Result

Enter a measurement and click Calculate.

Typical AA by Age (Push-Up)

Age	Avg AA (D)	Near Pt (cm)
10	14.0	7.1
20	11.0	9.1
30	8.0	12.5
40	5.0	20.0
50	2.5	40.0
60	1.0	100

Summary

The Accommodation Amplitude Calculator converts near point distance measurements into diopters using the push-up or minus lens method — the two techniques used in routine optometry exams. Enter the measurement values and the tool instantly returns the amplitude of accommodation alongside Hofstetter's age-based norms so clinicians can flag accommodative insufficiency at a glance.

How it works

Select the measurement method: Push-Up (near point distance) or Minus Lens.
For Push-Up: enter the near point distance in centimeters.
For Minus Lens: enter the working distance and the total minus lens power used.
Click Calculate to see the amplitude of accommodation in diopters.
Compare the result with Hofstetter's age-based norms shown below.

Use cases

Assess accommodative function in pediatric and adult patients.
Screen for accommodative insufficiency or excess.
Document baseline accommodation before prescribing reading lenses.
Monitor changes in accommodation amplitude over time.
Support clinical notes with quantified diopter values.
Cross-check push-up results with the minus lens method.

Frequently Asked Questions

Last updated: 2026-06-18 · Reviewed by Nham Vu