Effects of Extended Viewing Distance on Accommodative Response and Pupil Size of Myopic Adults by Using a Double-Mirror System

Shu-Yuan Lin, Hui-Rong Su, Chen-Cheng Lo, Shang-Min Yeh, Chi-Hung Lee, Richard Wu, Fen-Chi Lin, Yen-Wei Chu and Shuan-Yu Huang
Additional contact information
Shu-Yuan Lin: Ph.D. Program in Medical Biotechnology, National Chung Hsing University, Taichung 402, Taiwan
Hui-Rong Su: Department of Optometry, Chung Shan Medical University, Taichung 402, Taiwan
Chen-Cheng Lo: Department of Optometry, Chung Shan Medical University, Taichung 402, Taiwan
Shang-Min Yeh: Department of Optometry, Chung Shan Medical University, Taichung 402, Taiwan
Chi-Hung Lee: Department of Electrical Engineering, Feng Chia University, Taichung 407, Taiwan
Richard Wu: College of Optometry and Visual Science, Pacific University, Forest Grove, OR 97126, USA
Fen-Chi Lin: Department of Ophthalmology, Kaohsiung Armed Forced General Hospital, Kaohsiung 802, Taiwan
Yen-Wei Chu: Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
Shuan-Yu Huang: Department of Optometry, Chung Shan Medical University, Taichung 402, Taiwan

IJERPH, 2022, vol. 19, issue 5, 1-10

Abstract: Purposes: This study discussed the accommodative response and pupil size of myopic adults using a double-mirror system (DMS). The viewing distance could be extended to 2.285 m by using a DMS, which resulted in a reduction and increase in the accommodative response and pupil size, respectively. By using a DMS, the reduction of the accommodative response could improve eye fatigue with near work. Method: Sixty subjects aged between 18 and 22 years old were recruited in this study, and the average age was 20.67 ± 1.09. There were two main steps in the experimental process. In the first step, we examined the subjects’ refraction state and visual function, and then fitted disposable contact lenses with a corresponding refractive error. In the second step, the subjects gazed at an object from a viewing distance of 0.4 m and at a virtual image through a DMS, respectively, and the accommodative response and pupil size were measured using an open field autorefractor. Results: When the subjects gazed at the object from a distance of 0.4 m, or gazed at the virtual image through a DMS, the mean value of the accommodative response was 1.74 ± 0.43 or 0.16 ± 0.47 D, and the pupil size was 3.98 ± 0.06 mm or 4.18 ± 0.58 mm, respectively. With an increase in the viewing distance from 0.4 m to 2.285 m, the accommodative response and pupil size were significantly reduced about 1.58 D and enlarged about 0.2 mm, respectively. For three asterisk targets of different sizes (1 cm × 1 cm, 2 cm × 2 cm, and 3 cm × 3 cm), the mean accommodative response and pupil size through the DMS was 0.19 ± 0.16, 0.27 ± 0.24, 0.26 ± 0.19 D; and 4.20 ± 1.02, 3.94 ± 0.73, 4.21 ± 0.57 mm, respectively. The changes of the accommodative response and pupil size were not significant with the size of the targets ( p > 0.05). In the low or high myopia group, the accommodative response of 0.4 m and 2.285 m was 1.68 ± 0.42 D and 0.21 ± 0.48 D; and 1.88 ± 0.25 D and 0.05 ± 0.40 D, respectively. The accommodative response was significantly reduced by 1.47 D and 1.83 D for these two groups. The accommodative microfluctuations (AMFs) were stable when a DMS was used; on the contrary, the AMFs were unstable at a viewing distance of 0.4 m. Conclusions: In this study, the imaging through a DMS extended the viewing distance and enlarged the image, and resulted in a reduction in the accommodative response and an increase in the pupil size. For the low myopia group and the high myopia group, the accommodative response and pupil size were statistically significantly different before and after the use of the DMS. The reduction of the accommodative response could be applied for the improvement of asthenopia.

Keywords: accommodative response; pupil size; double-mirror system (DMS); accommodative microfluctuations (AMFs); fatigue; near work; myopia (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2022
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