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KMID : 1011420170220020133
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Journal of Korean Ophthalmic Optics Society
2017 Volume.22 No. 2 p.133 ~ p.142
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The Changes in Convergence Function of Accommodative Anomalies in their Twenties after Watching Video on a Smartphone
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Kim So-Ra
Kwak Ho-Wen
Kang Min-Sung
Kim Se-Il
Park Mi-Jung
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Abstract
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Purpose: The present study was conducted to investigate whether the change in visual function of accommodative anomalies in their twenties after watching video on a smartphone was different from that of normal subjects.
Methods: One hundred and thirty two subjects in their twenties (21.7±1.5 years) with a corrected or uncorrected visual acuity of 0.8 or better were examined and classified according to the visual function. The subjects were classified into normal, accommodative excess (AE), and accommodative insufficiency (AI) groups. Near point of convergence (NPC), phoria, AC/A ratio, were measured before and after watching video on a smartphone for 30 minutes.
Results: After watching video on a smartphone, NPC of AE and AI group tended to increase more than normal group. Distance and near phoria were shifted toward ortho position in all groups, distance phoria of normal and AE groups was significantly change. AC/ A ratio in AE and normal groups reduced after watching video on a smartphone and in normal group, it significantly decreased. Subjective symptoms such as eye fatigue, discomfort, and somnolence were increased in all groups. Diplopia was seen in the accommodative anomalies but not in the normal group.
Conclusions: From the results, it was confirmed that the change in visual function after watching video on a smartphone requiring constant accommodation and convergence for a period of time also varied due to individual difference in accommodation function. This study suggests that the working environment and the use time should be adjusted according to user"s accommodative function when using a smartphone.
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KEYWORD
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Smartphone, Accommodative anomalies, Near point of convergence, Phoria, AC/A ratio, Symptom
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