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B. Wang, K.J. Ciuffreda; Depth-of-focus of the Human Eye in the Near Retinal Periphery . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2728.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Although the depth-of-focus of the foveal region has been well investigated, knowledge about the effect of retinal eccentricity on blur sensitivity is very limited. This information is important, however, as under naturalistic viewing conditions, retinal defocus throughout much the visual field may influence the perception of blur and the resultant aggregate accommodative response. In the present study, the depth-of-focus was measured as a function of retinal eccentricity in the near periphery and compared with the foveal response. Methods: The depth-of-focus was measured at the fovea, as well as at retinal eccentricities of 0.5, 1, 2, 3, 4, 5, 6, 7 and 8 degrees. The psychophysical method of limits was employed. Subjects were comprised of 7 visually-normal adults 23 to 55 years of age. A Badal optometer system was used to present the stimuli consisting of variously-sized, high contrast, circular apertures concentric with the fovea. Accommodation of the tested right eye was paralyzed with 1% cyclopentolate; the non-tested left eye was fully occluded. Results: The group mean of the total depth-of-focus progressively increased linearly from 0.89 to 3.51 D with retinal eccentricity at the rate of 0.29 D/degree (r=0.86). For individual subjects, it ranged from 0.55 D to 1.55 D at the fovea and from 2.4 D to 5.1 D at an eccentricity of 8 degrees. The group mean SEM was relatively constant at each eccentricity, except at 8 degrees where it doubled in magnitude. When averaged across eccentricities, it was 0.17 D, with a range from 0.08 D to 0.35 D. Conclusions: The ability to detect defocused retinal imagery progressively worsened in the near retinal periphery. We speculate that this phenomenon may be attributed to various factors, including the cone dispersion and pooling, visual attention, optical aberrations, and divided visual attention. CR: None
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