不同调节视标下调节反应的比较

A comparison of accommodative responses to different accommodation targets

目的分析人眼在马耳他十字视标(Maltese cross)、E视标及快速序列视觉呈现(rapid serial verbal presentation,RSVP)系统汉字三种调节视标下的调节反应,探讨注视状态和阅读状态调节反应的差异。方法31位志愿者参加本实验,其中正视15位,等效球镜屈光力为-0.25～+0.50D;近视16位,均为稳定性近视,等效球镜屈光力为(4.06±2.00)D。利用精工SEIKO-WV500开放视野式自动验光仪测量调节反应,比较33cm处不同调节视标下,注视状态和阅读状态调节反应的差异。结果Maltesecross视标、E视标、RSVP汉字视标作为调节视标,调节反应分别为(2.07±0.35)D、(2.08±0.30)D、(1.88±0.42)D。其中RSVP汉字视标与E视标相比较,调节反应的差异有显著性(P=0.001),RSVP汉字视标与Maltese cross视标相比,调节反应的差异亦有显著性(P=0.003),而Maltese cross视标与E视标之间,调节反应差异无显著性。RSVP汉字作为调节视标时,个体间存在较大差异。不同调节视标下,正视组和稳定性近视组之间的调节反应均无显著差异。结论RSVP中汉字作为调节视标,在模拟阅读状态时和在低注意力情况下正自主性调节成分减少,调节反应降低。

Objective This study investigates accommodative responses to three different kinds of accommodative stimuli （Maltese cross, E visual target and Chinese characters in rapid serial visual presentation） and discusses the differences in accommodative responses when fixation targets and reading tasks were compared. Methods Thirty-one volunteers were enrolled in this study：15 emmetropes （-0.25±0.50 D） and 16 stable myopes [mean RE （4.06± 2.00）D]. Accommodative response was measured with an objective infrared autorefractor （SEIKO-WV500）. The differences were analyzed when the accommodative targets were presented at 33 cm. Results When the Maltese cross, E target and Chinese characters in RSVP were presented as accommodative targets, the accommodative responses were （2.07±0.35）D, （2.08±0.30）D and （1.88±0.42）D, respectively. Accommodative responses were significantly different between RSVP Chinese characters and either E letters （P=0.001） or Maltese cross targets （P=0.003）, but no significant differences in accommodation were found between E and Maltese cross accommodative targets. The accommodative response had much more variability among subjects when RSVP Chinese characters were used as the accommodative targets. However, there were no differences in accommodative responses between emmetropes and stable myopes. Conclusion When the accommodative targets are Chinese characters presented in RSVP to imitate a reading task requiring little attention, positive voluntary accommodation decreases so the overall accommodative response decreases.