Table 1.

Accommodative Amplitude before and 20 Minutes after 10% Phenylephrine Measured with Photorefraction

Monkey	Amplitude Before	Amplitude After	Difference
4	8.30 ± 0	7.56 ± 0.04	−0.74
20	11.40 ± 0.04	11.10 ± 0.06	−0.29
38	10.99 ± 0.16	12.30 ± 0.24	+1.32
70	11.85 ± 0.35	15.12 ± 0.25	+3.27
111	13.02 ± 0.04	12.10 ± 0.02	−0.91
Mean	11.11 ± 1.75	11.64 ± 2.72	+0.53 ± 1.77
111 control	11.57 ± 0.07	11.87 ± 0.07	+0.30

For the five monkeys receiving 10% phenylephrine and the saline control, accommodative responses to a single maximum stimulus amplitude measured with infrared photorefraction showed no significant difference in amplitude between the three prephenylephrine stimuli and the last three stimuli at 16, 18, and 20 minutes after phenylephrine (t-test: t = −0.6685, P = 0.54, df = 4), although individual monkeys showed differences, including the saline control monkey. Data are expressed in diopters (mean ± SD).