Visual form perception from age 20 through 80 years.
OBJECTIVE
We measured performance on a battery of visual form perception tasks for adults sampled evenly from each decade of adult life from 20 to 80 years.


METHODS
Measures were included that are considered to reflect processing at early through intermediate stages of the form processing pathways: collinear facilitation, center-surround contrast effects, global shape discrimination of contours of elements embedded in noise elements, and global shape discrimination in texture (Glass patterns). A total of 38 women and 20 men (mainly Caucasian, low refractive error) participated, aged between 20 and 82 years.


RESULTS
With advancing age, contrast sensitivity decreased linearly (B = 0.009, t(56) = 8.14, P < 0.001), perceptual surround suppression of low contrast stimuli embedded in higher contrast surrounds increased (B = -0.006, t(56) = -3.32, P < 0.01), and coherence thresholds for detecting form in Glass patterns increased (B = 0.14, t(56) = 2.53, P = 0.02). Performance between tasks was not correlated.


CONCLUSIONS
Several aspects of form perception alter gradually throughout the adult lifespan, namely context-dependent perception of contrast, and the extraction of global shape from texture. Our results suggested age-dependent differences under natural viewing conditions that are not predictable by standard clinical measures of visual function, and point to changes in neural function that are ongoing throughout adult life.
Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia. allisonm@unimelb.edu.au
Allison M
AM
McKendrick
Anne E
AE
Weymouth
Josephine
J
Battista
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology; D005260:Female; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D055815:Young Adult