JUNIPER
PUBLISHERS- JOJ Ophthalmology
Opinion
Although visual functions impairment are long been
well-recognized as an important factor in aging process, their
contribution to the problems of older persons on tasks in the natural
environment are not well known. The literature has shown age-related
deterioration of several visual function including visual acuity,
contrast sensitivity, dark adaptation, spatial vision and visual
processing speed, orientation and motion perception, stereopsis and
rivalry, and functional visual field.
All this age-related visual impairment that occurs
during normal (non-pathological) aging can be the result of optical,
retinal, and central visual pathways/cortical factors/changes. Although
optical factors can contribute to age-related declines, more recent
research suggests that the declines are primarily the result of cortical
changes (sensory and perceptual processing) and retinal/neuronal
changes. There are studies showing an age-related degeneration in
intracortical inhibition in V1 and in temporal processing speed in areas
17 and 18 [1].
Others studies have shown the trans-synaptic retrograde degeneration of
retinal ganglion cells following retrogeniculate visual pathway
lesions[2].
Neurophysiological studies suggest that processing declines may be due
in part to changes in the level of neurotransmitters associated with
cortical inhibition [3].
Recent findings indicate that visual impairment in
the elderly has significant influence on health and functional status,
with prognostic value as an independent predictor of mortality[4].
Others studies have found evidence that visual impairment increases the
risk of falls and fractures, institutionalization and disability to
perform basic activities of daily living. Similarly, elderly individuals
with decreased visual acuity are 5 times more likely to show impaired
cognitive and affective performance [5].
Research programs on how functional/structural eye changes during the
course of adulthood can provide information about risk factors or
biomarkers for the development of diseases or common conditions. For
example, is important to know the biological (e.g., neural, optical) and
environmental (e.g., smoking, dietary) factors that can influence the
normal versus the pathological aging (e.g., normal visual field for the
age).
This deterioration of visual functions related to age
makes important to recognize whether this decline can be recovered or
prevented. One promising approach in ameliorating age-related declines
in visual function is perceptual learning used to improved visual task
performance with practice. The results of our researches on Alzheimer
Disease versus Normal-Aging will eventually be useful to develop and
evaluate interventions to slow or reverse aging-related declines in
vision, thereby improving quality of life.
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