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Amplitude of accommodation is the maximum focusing power the eye can exert for near tasks. Clinicians estimate it with push-up or minus-lens methods or by applying Hofstetter formulas. Values decline with age as the lens stiffens. Results inform near prescriptions and task recommendations.
read more about amplitude of accommodation calculation ...Push-up testing moves a target toward the eye until blur is reported and converts distance to diopters. Minus-lens testing adds negative power in a phoropter until sustained blur occurs. Hofstetter formulas give expected values based on age for average, minimum, and maximum. Comparing measured and expected values guides diagnosis and management.
Average amplitude equals 18.5 minus 0.3 times age in years. Minimum equals 15.0 minus 0.25 times age. Maximum equals 25.0 minus 0.40 times age. Formulas provide benchmarks rather than absolute limits.
Diopters equal 100 divided by the near point in centimeters. For example, a 10 centimeter near point is about 10 diopters. Shorter distances indicate higher amplitudes. Consistent technique improves repeatability.
Push-up can overestimate due to angular size and depth of focus. Minus-lens can underestimate because of minification and testing posture. Using both with clinical context gives a balanced view. Age norms and symptoms help interpret results.
Values well below age-expected norms suggest accommodative insufficiency. Symptoms include near blur, fatigue, and headaches with close work. Refraction, binocular testing, and systemic review rule out other causes. Treatment may include plus lenses, therapy, or task adjustments.
The amplitude of accommodation refers to the maximum focusing power of the eye. It is the dioptric difference between the far point and the near point of clear vision.
Eye care professionals measure it using the push-up method (moving text toward the eye until it blurs) or with lenses that stimulate accommodation. The result is given in diopters.
It indicates the focusing flexibility of the lens. Reduced amplitude is associated with presbyopia and influences the need for reading glasses or multifocal lenses.