Age‐related changes of defocus‐specific contrast sensitivity in healthy subjects

Abstract

To investigate the effect of defocus on contrast sensitivity as a function of age in healthy subjects, the through focus contrast sensitivity was measured in 100 healthy subjects aged 20-69. Defocus-specific changes in contrast sensitivity reflect age-related changes in the optics of the eye. Tests were performed in cycloplegic eyes varying artificial pupil size (2, 4 and 6 mm), defocus (-1 to +2 D), and spatial frequency (1-16 cpd). Integrated contrast sensitivity was taken as a measure for the total amount of visual information transferred by the optical media. At optimal focus, integrated contrast sensitivity and log contrast sensitivity at 8 cpd showed a significant age-related decline. The log contrast sensitivity at 1 cpd appeared to be independent of age. The depth of focus for a 4-mm pupil increased significantly with age, even though contrast sensitivity at +2 D defocus decreases with age too, but not as much as the contrast sensitivity at optimal focus. Our study indicates that the effect of defocus on contrast sensitivity decreases with age; this was attributed to age-related changes in the optical media.

Aging effects on the identification of digitally blurred text, scenes and faces: Evidence for optical compensation on everyday tasks in the senescent eye

“…With additional blur, however, observers with normal vision were affected more than were the vision-impaired to the extent that thresholds of the two groups were equalized on the tasks. More recently, Nio, Jansonius, Fidler, Geraghty, Norrby and Kooijman (2000) have shown that the adverse effects of optical defocus on contrast sensitivity are reduced among older observers, an effect that they attributed to changes in the optical media of the older eye. Certainly, the older eye's smaller pupil would tend to counter the effect of optical defocus.…”

Contrast sensitivity test and conventional and high frequency audiometry: information beyond that required to prescribe lenses and headsets

“…Hereby we consider tests employing achromatic sine patterns which can be displayed either on a monitor (e.g. Cambridge Research Systems VSG 2/3 [9,10] and Vistuc [5]) or on charts (e.g. Vector Vision TM CSV-1000 [4,11] and Vistech [3]).…”

“…Concerning the plot CSF vs U, log contrast sensitivity, log CSF=log 10 (((L max +L min )/(L max -L min )) object,threshold ) is often [3-6] plotted ( Fig.1 (left)), its peak being [6] at 3cpd to 7cpd. The coordinates used in the absisas varies according to various authors, the scale being linear [11], base 10 logarithmic [6][7][8], base 2 logarithmic [9] or corresponding [3,5] to a real number k such that U=U o 2 k (e.g. U o =1.5cpd in the Vistech [3] while U o =0.25cpd in the Vistuc [5]).…”

“…The contrast sensitivity test is the most accurate method of measuring sensitivity of all the visual channels [3], it informs about the ability of a subject to perceive patterns corresponding to a wide range of effective spatial frequencies and contrasts and it is a valuable tool for an early non invasive diagnose of pathologies both exclusive and inclusive of the visual system. Concerning vision, it is useful to evaluate the global visual performance of subjects that wear contact lenses [3], have intraocular implants [11], suffer from cataracts [3], underwent refractive surgery [10], suffer from macular degeneration or glaucoma [3], are aging [9], perform demanding visual tasks [12] or sports [3], etc. [5,6].…”

“…There are both objective and subjective tests to evaluate visual and auditory performance. In this work we consider two subjective tests that are based in Fourier theory [2]; are similar to each other [3,4] and measure sensitivity as a function of spatial and temporal frequency respectively, the contrast sensitivity test [3][4][5][6][7][8][9][10][11][12][13] and conventional and high frequency pure tone audiometry [14][15][16][17][18][19][20][21][22]. In Table 1 we summarize a parallelism between the eye and ear which we treat in more detail in the following sections.…”