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Evaluation of binocular vision parameters as screening indicators for asthenopia
Guan-Cheng Lin1, Pei-Ru Huang1, Yueh-Jung Chen1
1Department of Optometry, Chung Hwa University of Medical Technology, Tainan, Taiwan.
Purpose:
To investigate the feasibility of using binocular vision parameters as relatively objective indicators for screening asthenopia, thereby reducing reliance on subjective questionnaires.
Methods:
50 young Taiwanese adults (mean age: 28.60 ± 4.26 years) were recruited. All participants completed the Convergence Insufficiency Symptom Survey Questionnaire (CISS-Q) and underwent binocular vision tests, including measurements of negative relative accommodation (NRA), positive relative accommodation (PRA), near point of accommodation (NPA), near point of convergence (NPC), and binocular accommodative facility (BAF). Participants were subsequently assigned into an asthenopia group (n = 26) and a non-asthenopia group (n = 24) based on their CISS-Q scores (post-hoc grouping). Comparisons between groups were performed using the Mann-Whitney U test. Parameters that showed significant differences were further analyzed using receiver operating characteristic (ROC) curve analysis to evaluate the efficacy of binocular vision parameters for screening asthenopia.
Results:
Significant differences were found between the asthenopia and non-asthenopia groups in binocular vision parameters, including NRA, PRA, NPC, and BAF (all p < 0.001). ROC curve analysis and Youden's index revealed that PRA demonstrated the highest screening efficacy (cut point: -2.25 D; sensitivity: 88.5%; specificity: 91.7%), followed by NPC (cut point: 2.25 cm; sensitivity: 84.6%; specificity: 75%) and NRA (cut point: + 1.88 D; sensitivity: 65.4%; specificity: 95.8%).
Conclusion:
This study proposes the PRA cut point of -2.25D, which exhibits high sensitivity and specificity in asthenopia screening. With further validation, it may serve as a novel indicator in clinical practice.
Key Messages:
What is known Asthenopia is primarily assessed using subjective questionnaires, such as the Dry Eye Questionnaire, Computer Vision Syndrome Questionnaire (CVS-Q), and Convergence Insufficiency Symptom Survey Questionnaire (CISS-Q), which may be limited by symptom specificity and subjective responses. What is new Binocular vision parameters may have the potential as relatively objective indicators for screening asthenopia. This study proposes a PRA cut point of -2.25 D, which demonstrates high sensitivity (88.5%) and specificity (91.7%) for screening asthenopia, providing a novel clinical application. PRA is already a component of routine optometric examinations. It can be directly applied in clinical practice without requiring additional equipment or procedures.
