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R.O. Beirne, M.B. Zlatkova, R.S. Anderson; How does the short–wavelength–sensitive contrast sensitivity function for detection and resolution change with age in the periphery? . Invest. Ophthalmol. Vis. Sci. 2004;45(13):3436.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: The shape and cut–off point at the high spatial frequency end of the human contrast sensitivity function for gratings under conditions of blue cone isolation in peripheral vision are significantly different depending on whether the psychophysical task is detection acuity (optically limited) or resolution acuity (retinal ganglion cell sampling limited). We wished to examine any changes in the high spatial frequency end of the short–wavelength–sensitive (SWS) contrast sensitivity function with age for both detection and resolution of these gratings. Methods: 29 normal subjects with no known ocular pathology divided into two age groups (17 subjects, 19–29 yrs; 12 subjects, 54–72yrs). Short–wavelength resolution acuity for both cut–off detection (2AFC temporal) and resolution (2AFC spatial) was measured at 8 degrees eccentricity from the fovea in meridians 90 and 270. Contrast sensitivity was measured for detection and resolution at the same two retinal locations at three spatial frequencies of 0.05, 0.15 and 0.32 log units less than the cut–off for resolution acuity. Results: 2–way ANOVA with age group (young or old) and task (detection or resolution) as factors showed that age had a significant effect on cut–off acuity (p<0.01) as did the task (p=0.02)(3.04 cyc/deg vs. 2.57cyc/deg; 2.04 cyc/deg vs. 1.71 cyc/deg respectively). No significant interaction between age and task (p=0.73) was found indicating that the change in acuity with age was similar for both detection and resolution. At that spatial frequency 0.05 log units less than the cut–off for resolution acuity, task had a significant effect on contrast sensitivity with detection acuity significantly higher than resolution acuity for both groups (p=0.04). Test type did not have a significant effect on contrast sensitivity at the two lower spatial frequencies used. Contrast sensitivity was on average 0.2 log units lower in the older group at spatial frequencies below their cut–off for resolution acuity when compared to the younger group. Conclusions:Cut–off spatial frequency and contrast sensitivity for SWS–isolating gratings in peripheral vision are affected by increasing age, with a similar change for both a detection and resolution task. The decline with age in resolution contrast sensitivity can be explained by a decrease in the underlying retinal ganglion cell density. The decline in detection contrast sensitivity with age may be a combination of neural changes and pre–retinal factors, including increased lens yellowing with age.
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