|
Amplitude of Accommodation：
Push-Up Method
PURPOSE This procedure measures in diopters a patient’s ability to change the focus of the eye’s crystalline lens in response to a near stimulus．
EQUIPMENT
·Near point visual acuity card．
·Tape measure in centimeters．
·Occluder．
SET-UP
·The patient is tested wearing his habitual distance correction．This test may also be performed behind the phoropter as a part of the postrefraction phorometry sequence．
·Either the patient or the examiner may hold the near point card．
·The near point card should be well illuminated．
STEP-BY-STEP PROCEDURE
1．Instruct the patient to occlude his left eye to test his right eye．
2．Direct the patient’s attention to a row of letters one or two lines larger than his near VA．
3．Instruct the patient to keep the letters clear．
4．Slowly move the chart closer to the patient and ask the patient to report when the letters become and remain blurry．
5．Measure the distance from the chart to the patient’s spectacle plane in centimeters．The linear measurement is referred to as the nearpoint of accommodation．
6．Convert the linear distance into diopters by dividing the number of centimeters into 100．The resulting dioptral value represents the patient’s amplitude of accommodation．
7．Occlude the right eye and test the left eye using steps 1 to 6．
RECORDING
·Record the method of testing used．
·Record the amplitude of accommodation in diopters (round off to the nearest half diopter)．
·Separately record the results for the right and left eyes．
EXAMPLES
Amp (push ) OD 7D OS 7D
Amp (push ) OD 6D OS 6D
EXPECTED FINDINGS
·The expected amplitude of accommodation decreases with age．The two most commonly used systems for obtaining the expected amplitude of accommodation are：
a．Hofstetter’s formulas
1) Minimum expected amplitude=15-0.25(age)
2) Average expected amplitude=18.5-0.30(age)
31 Maximum expected amplitude=25-0.40(age)
b．Donders’ table (see Table 2-2)
·The amplitude of accommodation of the two eyes should be within one diopter of each other． |
