Psychophysical experiments, with a new paradigm but in broad conformity with classical results on glare, were used to estimate the scattering in the eye. Combining the data with those from a companion experiment [
J. Opt. Soc. Am. A 12,
1411–
1416 (
1995)] using objective double-pass measurements of the retinal image in the same subjects permitted a synthesis of the complete point-spread function. Results were obtained on two young subjects and one older one with more prominent scatter but normal visual acuity. This permitted the derivation of performance parameters of the eyes, such as the Strehl ratio and cumulative light functions. When the scattering was more prominent, we were able to characterize performance losses that manifested themselves in changes in absolute and contrast detection thresholds.
Pablo Alejandro Barrionuevo, Elisa Margarita Colombo, Meritxell Vilaseca, Jaume Pujol, and Luis Alberto Issolio J. Opt. Soc. Am. A 29(7) 1293-1299 (2012)
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Psychophysical Measurements of Retinal Illuminance in the Center of Dark Disks as a Fraction of the Illuminance of the Annular Surrounda
Obscuring Disk Diameter (arcmin)
Subject
30′
60′
120′
240′
360′
JL (age 30)
0.049
0.043
0.035
0.029
0.025
VL (age 21)
0.062
0.047
0.037
0.025
0.023
GW (age 69)
0.300
0.214
0.209
0.160
0.130
Ratio of light intensity at the center of obscuring disks to light intensity of points within annular surround for five inner diameters and constant outer diameter of 20 deg. Data represent the separate lateral shifts (difference in logarithmic coordinates) needed for superimposing threshold curves on the right-hand side of Fig. 3 onto the leftmost curve, i.e., the curve for a uniform field.
Table 2
Proportion of Total Light Flux from a Point Source Falling into Annular Zones of the Retinal Image of Given Inner and Outer Radiia
P1
P2
P3
Q
Subject
0.25–1 deg
1–3 deg
3–10 deg
>7′
JL
0.014
0.010
0.025
0.095
VL
0.025
0.014
0.023
0.106
GW
0.091
0.079
0.130
0.540
P1, P2, P3, proportion of total light from a point source that falls into annular zones of the retinal image with indicated inner and outer radii. Q, proportion of the total flux calculated to fall into the image zone beyond a radius of 7 arcmin (see text for details).
S1, interim Strehl ratio derived from the point-spread distribution within 7 arcmin, from double-pass measurements; E, the fraction of the volume of the PSF beyond 7 arcmin, obtained by extrapolation of psychophysical measurements; S, the real Strehl ratio. Y and GW represent the young eyes (average) and the older eye (of GW), respectively.
Table 4
Proportion of Total Light from a Point Source Falling in Annular Zones of the Image with Given Inner and Outer Radiia
A and n, the two parameters in the glare formula of Eq. (A1). P1, P2, P3, P4: Proportion of total flux from a point source falling into annular zones of the retinal image with, respectively, 0.25-deg inner radius and 1-deg outer radius, 1-deg inner radius and 3-deg outer radius, 3-deg inner radius and 10-deg outer radius, and 10-deg inner radius and 50-deg outer radius. TR, actual test regions of the original experiments, in degrees.
Tables (4)
Table 1
Psychophysical Measurements of Retinal Illuminance in the Center of Dark Disks as a Fraction of the Illuminance of the Annular Surrounda
Obscuring Disk Diameter (arcmin)
Subject
30′
60′
120′
240′
360′
JL (age 30)
0.049
0.043
0.035
0.029
0.025
VL (age 21)
0.062
0.047
0.037
0.025
0.023
GW (age 69)
0.300
0.214
0.209
0.160
0.130
Ratio of light intensity at the center of obscuring disks to light intensity of points within annular surround for five inner diameters and constant outer diameter of 20 deg. Data represent the separate lateral shifts (difference in logarithmic coordinates) needed for superimposing threshold curves on the right-hand side of Fig. 3 onto the leftmost curve, i.e., the curve for a uniform field.
Table 2
Proportion of Total Light Flux from a Point Source Falling into Annular Zones of the Retinal Image of Given Inner and Outer Radiia
P1
P2
P3
Q
Subject
0.25–1 deg
1–3 deg
3–10 deg
>7′
JL
0.014
0.010
0.025
0.095
VL
0.025
0.014
0.023
0.106
GW
0.091
0.079
0.130
0.540
P1, P2, P3, proportion of total light from a point source that falls into annular zones of the retinal image with indicated inner and outer radii. Q, proportion of the total flux calculated to fall into the image zone beyond a radius of 7 arcmin (see text for details).
S1, interim Strehl ratio derived from the point-spread distribution within 7 arcmin, from double-pass measurements; E, the fraction of the volume of the PSF beyond 7 arcmin, obtained by extrapolation of psychophysical measurements; S, the real Strehl ratio. Y and GW represent the young eyes (average) and the older eye (of GW), respectively.
Table 4
Proportion of Total Light from a Point Source Falling in Annular Zones of the Image with Given Inner and Outer Radiia
A and n, the two parameters in the glare formula of Eq. (A1). P1, P2, P3, P4: Proportion of total flux from a point source falling into annular zones of the retinal image with, respectively, 0.25-deg inner radius and 1-deg outer radius, 1-deg inner radius and 3-deg outer radius, 3-deg inner radius and 10-deg outer radius, and 10-deg inner radius and 50-deg outer radius. TR, actual test regions of the original experiments, in degrees.
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