|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|6203279||1603189||2014||9 صفحه PDF||سفارش دهید||دانلود رایگان|
- Linear relationship between stimulus and response vergence accommodation measures.
- Agreement between stimulus and response measures stronger for accommodative vergence.
- Variability in vergence response to the target used to open accommodation loop.
- The appropriate target for vergence accommodation measurement requires further study.
Stimulation of the accommodation system results in a response in the vergence system via accommodative vergence cross-link interactions, and stimulation of the vergence system results in an accommodation response via vergence accommodation cross-link interactions. Cross-link interactions are necessary in order to ensure simultaneous responses in the accommodation and vergence systems. The crosslink interactions are represented most comprehensively by the response AC/A (accommodative vergence) and CA/C (vergence accommodation) ratios, although the stimulus AC/A ratio is measured clinically, and the stimulus CA/C ratio is seldom measured in clinical practice. The present study aims to quantify both stimulus and response AC/A and CA/C ratios in a binocularly normal population, and determine the relationship between them. 25 Subjects (meanÂ Â±Â SD age 21.0Â Â±Â 1.9Â years) were recruited from the university population. A significant linear relationship was found between the stimulus and response ratios, for both AC/A (r2Â =Â 0.96, pÂ <Â 0.001) and CA/C ratios (r2Â =Â 0.40, pÂ <Â 0.05). Good agreement was found between the stimulus and response AC/A ratios (95% CI â0.06 to 0.24Â MA/D). Stimulus and response CA/C ratios are linearly related. Stimulus CA/C ratios were higher than response ratios at low values, and lower than response ratios at high values (95% CI â0.46 to 0.42Â D/MA). Agreement between stimulus and response CA/C ratios is poorer than that found for AC/A ratios due to increased variability in vergence responses when viewing the Gaussian blurred target. This study has shown that more work is needed to refine the methodology of CA/C ratio measurement.
Journal: Vision Research - Volume 105, December 2014, Pages 121-129