【摘要】 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~+0.50 D;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33 cm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 Maltese cross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。
【关键词】 调节反应;自主性调节;正视;近视;稳定性近视
DENG Ruzhi, LU Fan, BAO Jinhua, et al.
School of Optometry & Ophthalmology, Wenzhou Medical College, Wenzhou China,325027
[Abstract] 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.
[Key words] accommodation response; voluntary accommodation; emmetropia; myopia; stable myopia
马耳他十字视标(Maltese cross)为测量调节反应的经典视标,该视标中央可提供良好的细节,使受试者维持稳定注视,还可通过改变臂长,以获得不同注视距离的相同视角。E视标亦是常用的调节视标,它能够提供较好的细节以及相对稳定的空间频率。由于调节反应还受到受试者注意力影响,在阅读状态下和非阅读状态下,可能由于注意力的不同存在调节差异。Maltese cross视标与E视标均为注视视标,不具有可阅读性。Gilbert等[1]首次采用快速序列视觉呈现(rapid serial verbal presentation,RSVP)技术研究阅读相关参数,通过特殊软件,阅读材料可设定在电脑屏幕中的固定位置,其字体、大小、呈现速度以及呈现内容均可按需要选择,保证了阅读时受试者无头部运动和眼球运动的参与。因此,利用RSVP系统中文字作为调节视标,既可模拟阅读状态,又能比较容易地测量调节反应。本研究将在正视和近视研究对象中,利用以上三种视标作为调节视标,采用客观调节反应测量方法,探讨注视状态和阅读状态下调节反应量的差异,为研究阅读状态下其他各项视功能参数奠定基础。
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