Double-pass and interferometric measures of the optical quality of the eye

Abstract

We compare two methods for measuring the modulation transfer function (MTF) of the human eye: an interferometric method similar to that of Campbell and Green [J. Physiol. (London) 181,576 (1965)] and a double-pass procedure similar to that of Santamaria et al. [J. Opt. Soc. Am. A 4, 1109(1987]. We implemented various improvements in both techniques to reduce error in the estimates of the MTF. We used the same observers, refractive state, pupil size (3 mm), and wavelength (632.8 nm) for both methods. In the double-pass method we found close agreement between the plane of subjective best focus for the observer and the plane of objective best focus, suggesting that much of the reflected light is confined within individual cones throughout its double pass through the receptor layer. The double-pass method produced MTF's that were similar to but slightly lower than those of the interferometric method. This additional loss in modulation transfer is probably attributable to light reflected from the choroid, because green light, which reduces the contribution of the choroid to the fundus reflection, produces somewhat higher MTF's that are consistent with the interferometric results. When either method is used, the MTF's lie well below those obtained with the aberroscope method [Vision Res. 28, 659 (1988)]. On the basis of the interferometric method, we propose a new estimate of the monochromatic MTF of the eye.

Spatio-temporal Contrast Sensitivity in the Cardinal Directions of the Colour Space. A Review

“…As can be seen in figure 4, however, the results obtained with this technique do not differ in anything essential from those derived with an interferometric method. 38 At any frequency, contrast sensitivity is basically the same at θ=0 rad and θ=π/2 rad, but a significant sensitivity reduction is found at around θ=π/4 rad, especially for higher frequencies, which results in a loss of resolution when measurements are carried out with gratings having this orientation. [39][40][41] This behaviour of the visual system is well known, and has been named the "oblique effect".…”

Refractive analysis of the human cornea through propagated fields

“…This method consists of de ning the topography of this surface and studying the di raction eld generated by it. This requires an accurate numerical evaluation of expression (1).…”

“…Di erent objective methods have been applied to measure the optical impulse response of the eye (excluding the retinal response) [1,2]. The double-pass technique has been successfully applied to obtain the modulation transfer function of the optics of the visual system [3], but, again, the di erent surfaces are not directly accessible.…”

“…Finally, note that this analysis can also be combined with the results obtained with the double-pass technique [1]. Once the optical performance of the cornea is substracted from that obtained for the whole eye, we will have instant access to the inner part of the eye, which cannot be accessed any other way.…”

Measurement of straylight for glare assessment and driving.

“…This method uses the so-called double pass or DP approach. Since the DP approach is hampered by strong artefacts (van den Berg, 2010;Williams, Brainard, McMahon, & Navarro, 1994) the authors adapted the approach to avoid relevant artefacts. In particular, dp suffers from spurious light scattering phenomena, such as light diffusion in the choroid, and back scatter in the optical media.…”