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Zhili Zheng, Rongrong Le, Ruijun Wang, Fan Lu; Accommodative Responses to Face Images with Different Clarity and Orientation. Invest. Ophthalmol. Vis. Sci. 2012;53(14):4815.
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© ARVO (1962-2015); The Authors (2016-present)
To study accommodation during the process of high-level visual perception by measuring accommodative responses to artificial face images with different clarity and orientation.
Accommodative response and fluctuation were continuously measured using an infrared automatic refractometer (WAM5500, Grand Seiko Co. Ltd) at a frequency of 5Hz for 90 seconds in each test condition for eight normal students (mean age 25 years, range 24-27 years; visual acuity of 20/20 or better). Three types of face images with different clarity (blur, clear and sharp) were created by adjusting frequency slope (s=-1.00, 0, or +1.00) in spectrum domain to enhance low frequency, normal or high frequency information. The face images were presented at 0.33 m with opposite orientations: face up or face down.
Accommodative response varied significantly against different levels of clarity (F=54.94, p<0.01) and opposite orientations (F=23.61, p<0.01), but accommodative fluctuation did not change significantly (F=2.69, p=0.07 for the clarity; and F=0.18, p=0.67 for orientation). Accommodative response was weakest to blur face images (1.72±0.68D), compared with clear (1.92±0.47D, p<0.01) and sharp images (1.93±0.36D, p=0.0037, multiple comparison with p adjusted with Benjamini & Hochberg’s method). There was no significant difference in accommodative response between clear and sharp images. The higher accommodative response was also found in response to face-up image than to face-down one (1.90±0.45D vs. 1.81±0.59D, F=23.61, p<0.01).
Accommodative response depends on both clarity and orientation of face images. The results suggest that accommodation is sensitive to high spatial frequency and also modified by visual perception. Accommodative fluctuation may be controlled by internal feedback of visual information and doesn’t change with different image clarity and high level perception.
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