Purpose: The accommodative response and the near horizontal phoria were examined with additional spherical power to analyze the stimulus and response AC/A ratios that suggest reference data for the binocular vision.Methods: The open-field autorefractometer (Nvision-K 5001, Shin nippon) and modified thorington method (MIM card; Muscle Imbalance Measure card, Bernell) at 40 cm were utilized to measure the accommodative response and the near horizontal phoria for 81 persons (20.89±1.92 years old) with additional spherical power. The stimulus and the response AC/A ratios were calculated by gradient AC/A method. Results: The exophoria group showed the highest accommodative response (1.92±0.26 D) at 40 cm, followed by orthophoria group and esophoria group(1.72±0.26 D and 1.62±0.42 D, respectively) Meanwhile, the esophoria group showed the biggest ocular deviation for the near (23.24 ∆) followed by the orthophoria group and exophoria group (19.76 ∆ and 15.14 ∆, respectively). The biggest difference of the stimulus and the response AC/A ratios was 1.72 ∆ for the exophoria group with −2.00 D, while the one was 3.43 ∆ for the esophoria group with +1.00 D. There was a significant difference between AC/A ratios for the exophoria group with −2.00 D, −1.00 D and the esophoria group with +3.00 D, +2.00D, +1.00D and −1.00D. Conclusions: The difference between stimulus and response AC/A was greater when increased minus spherical power for the exophoria group, while it was greater when increased plus spherical power for the esophoria group. Furthermore, the difference for the esophoria group was a greater than the one for the exophoria group.

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Purpose: This study investigated accommodative changes by measuring accommodative response, appearing on the normal and convergence insufficiency Group, by using both eyes open-view auto-refractometer (Nvision-K5001, shin-nippon, Japan). Methods: It carried out objective and subjective refractions, targeting 74 college students (54 males and 20 females) aged between 19 and 29 (21.59±2.53), spherical equivalent OD −2.28±2.03 D, OS −2.18±2.01 D, by measuring accommodative responses at full correction and under correction with plus lens +0.25, +0.50, +0.75 arbitrarily added. Results: In the group of normal and convergence insufficiency, the shorter fixation distances were, the greater accommodative lags showed. The group of convergence insufficiency showed the lesser changes of accommodative response than those of normal. But we found that the convergence insufficiency group had a little larger accommodative amplitude in the total fixation distances. The full correction of convergence insufficiency group and the under correction (+0.50 D) of normal were alike in the accommodative responses. We have also investigated that the correlation between accommodative responses and fixation distances was decreased steeply at the excessive low vision correction. Conclusions: Under correction (+0.50 D) in a near distance is expected to avoid unnecessary accommodative responses, make eyes relaxed and comfortable

································································································································································································································Purpose: To compare the convergence accommodation to convergence (CA/C) ratios with varying prismatic powers and base among three clinical methods. Methods: 52 young adult subjects (mean age of 21.68±2.57 years, 32 males and 20 females) with normal binocular vision participated in this study. After measure diatance and near binocular function include phoria test and accomodation, accommodative response was measured using the open-field autorefractor (NVision K-5001, Shin-Nippon, Japan), the Streak Retinoscope (WEL18245, Welch Allyn, America) and the BCC (binocular crossed cylinder). While accommodative response was measuring, prismatic powers and base were also varied. CA/C ratios was calculated base on the accommodative response. Results: Accommodative response were high in the order of BCC, AR, and Nott method at all prismatic power and base. As the prismatic power was increased from the prismatic base of the BI to the BO, accommodative response was also gradually increased. The mean of the CA/C ratios in all prismatic powers and bases was higher in the order of BCC, AR, and Nott method. For persons with normal binocular function, the mean of the CA/C ratios measured by 6 Δ, BI was 0.095±0.012 D/Δ in BCC, 0.093±0.012 D/Δ in AR, 0.088±0.009 D/Δ in Nott method, respectively. The mean and standard deviation for 6 Δ, BI was the smallest in all methods and there was no statistically significant difference (F = 2.532, p = 0.085). Conclusions: When the CA/C ratios was measured by the Nott method, the most consistent result was obtained regardless of the prismatic power and the base.

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