Abstract:

Objective To investigate factors associated with visual display terminal (VDT) related asthenopia. Design A prospective comparative case series. Participants 141 cases of adult subjects who often performed VDT operation. Methods 141 cases of adult human subjects, after informed consent being obtained, were exposed to one-hour computer operation (VDT operation). Eye movement parameters with refractive error correction, including the amplitude of accommodation (AA), near point of convergence, the ratio of accommodative convergence and accommodation (AC/A), phoria at distance and near, positive and negative relative accommodation(PRA and NRA) and stereoscopic detection were measured before the VDT operation. Visual fatigue questionnaire was performed for each subject after VDT operation and VDT visual fatigue was diagnosed if 2 or more symptoms were found. Univariate and multivariate analyses were performed to determine the parameters related to the occurrence of VDT related asthenopia. Logistic regression analysis was used in multivariate analysis. Main Outcome Measures AA, near point of convergence, AC/A, phoria at distance and near, PRA and NRA, stereoscopic detection, visual fatigue questionnaire. Results In 141 investigated objects, VDT related asthenopia occurred in 43(30.50%) cases. In the 43 cases of VDT related asthenopia, 32 were women(36.78%), which was significantly higher than that of men (11 cases, 20.4%) (χ2=4.597, P=0.032). The univariate analysis showed that compared to the asymptomatic group, the VDT related asthenopia group had significantly lower AA (3.98±1.52 D) and AC/A (2.47±0.84) value (P=0.003); and further near point of convergence (9.87±1.76 cm) (P=0.001), higher exophoria at distance indicated by close distance phoria, PRA and NRA (all P=0.001). Subjects with abnormal stereoscopia detected by Titmus stereo vision (>60 s) were more easily suffer from VDT related asthenopia (P=0.002). Logistic regression analysis indicated that the near distance phoria were related risk factors of VDT-related asthenopia. Higher AC/A, the ability of stereoscopic vision and greater PRA were protective factors for the pathogenesis of VDT related asthenopia. Conclusion Lower AC/A, larger near distance phoria degree, less PRA and abnormal stereoscopic vision are independent risk factors for the pathogenesis of VDT related asthenopia.  （Ophthalmol CHN, 2016，25： 110-114）

Key words: asthenopia, visual display terminal, refraction, accommodative, convergence, risk factor