Purchase this article with an account.
RS Anderson, MB Zlatkova, RO Beirne; The Contrast Sensitivity Function for Detection and Resolution of Blue-yellow Gratings in Foveal and Peripheral Vision . Invest. Ophthalmol. Vis. Sci. 2002;43(13):3790.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Previous achromatic studies have shown that the peripheral grating contrast sensitivity function (CSF) is significantly different when the task is resolution rather than detection. Specifically, while detection performance continues to high spatial frequencies (up to 30 cycles/degree; Thibos et al, 1996), resolution acuity drops suddenly to zero in the middle frequency range, accompanied by observations of aliasing, indicating that peripheral achromatic resolution acuity is sampling, rather than contrast limited. Presently, however, there is little information on how the detection and resolution CSF's compare for the short wavelength sensitive (SWS) system either foveally or peripherally. Is SWS resolution acuity also sampling limited in the fovea or periphery? Methods: CSF's were measured at the fovea and 20 degrees eccentricity in the temporal retina (with peripheral refractive correction) under conditions of SWS-cone pathway isolation. The grating contrast sensitivity thresholds were obtained from psychometric functions at different spatial frequencies for both contrast detection and orientation identification tasks using a two-alternative forced choice paradigm. Results: The detection and resolution CSF were identical at the low frequency end, but at higher frequencies resolution CS falls abruptly to zero while contrast detection continues until higher frequencies (cut-off frequency: fovea detection 7 cycles/degree, resolution 4 cycles/degree; periphery detection 1.3 cycles/degree, resolution 0.9 cycles/degree). Chromatic aliasing was observable when spatial frequency exceeded the resolution limit. Conclusion: SWS-driven resolution acuity is sampling limited in both the fovea and periphery. Previous studies of SWS-contrast sensitivity, which typically employed a detection task, have been limited by grating contrast and don't reflect the true resolution limit. Our results indicate that the resolution limit is substantially lower when the performance is limited by retinal sampling rather than contrast.
This PDF is available to Subscribers Only