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KMID : 1011420220270040263
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Journal of Korean Ophthalmic Optics Society
2022 Volume.27 No. 4 p.263 ~ p.267
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Variations in the Measured AC/A Ratio Depending on Accommodative Stress and Spherical Powers for Accommodative Induction
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Noh Jae-Hyeon
Moon Byeong-Yeon
Yu Dong-Sik
Kim Sang-Yeob
Cho Hyun-Gug
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Abstract
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Purpose: To investigate the variations in measured AC/A ratio depending on the accommodative stress and spherical powers for accommodative induction.
Methods: The near lateral heterophoria and AC/A ratio were measured using the modified Thorington chart and the horizontal red Maddox rod after subjective refraction for 25 participants (7 males, 18 females, mean age 20.96±1.54). Then, after accommodative stress induced by watching a video for 30 min, near lateral heterophoria and AC/ A ratio were measured. For AC/A ratio measurements, +2.50 D, +2.00 D, +1.00 D, ?1.00 D, ?2.00 D, and ?2.50 D of spherical lenses were used for accommodative induction, respectively.
Results: As a result of comparing the AC/A ratio measured before and after accommodative stress, there was no statistically significant difference between the two conditions. However, in case of AC/A ratio measured by the (+) powers, the AC/A ratio decreased as the (+) power increased. In case of AC/A ratio measured by the (-) powers, the AC/A ratio increased as the (?) power increased, and as a result of comparing the AC/A ratio measured at ±2.50 D, ±2.00 D, and ±1.00 D, there was a statistically significant difference at ±2.50 D (p<0.05) between two conditions. As a result of analyzing the correlation between the AC/A ratio measured before/after the accommodative stress and lateral heterophoria, there was no significant difference between the AC/A ratio and lateral heterophoria before the accommodative stress. After accommodative stress, there was a significant difference between the AC/A ratio measured with +2.50 D and +2.00 D and the lateral heterophoria (p<0.05).
Conclusions: Tests related to AC/A ratio measurement and accommodation must be performed by maintaining a state of accommodation relaxation before the test.
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KEYWORD
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Accommodative stress, AC/A ratio, Accommodative stimulation, Accommodation, Convergence
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