Development of the Visual System The visual system begins to mature in the early years of life and keeps adapting and changing till old age.
Infants:
Newborns have uncoordinated and poor saccadic eye movement. it isn't till 6 months that fixation is effective and the lens accommodation is close to adult levels. The rods are adult-like in newborns, but the cones are much thicker and can't absorb as much light. Only with maturity do cones become narrower and longer travelling to form fovea. All this leads to better acuity and color vision in the first six months of life. The acuity and contrast sensitivity, ability to see distinguish varied size objects, is very poor in newborns. For instance, at birth acuity is around 20/400 to 20/800 and by 6 months it's …show more content…
The cornea, goes through minor changes such as increase in cornea thickness and curvature increasing the possibility of astigmatism. Aging also results in reduction of pupil size, number of rods, and retinal ganglion cells. Changes in eye movements are also prominent in old age with a decline in smooth pursuit eye movement (ability of eyes to closely follow a object) and saccadic eye movement (rapid movement of eyes that abruptly change fixation point). Fixation stability appears to have little effect on aging adults. They are able to maintain stable gaze for long time. Other noticeable changes as a result of age related decline are difficulty in performing under dim illumination due to a decline in the dark-adapted sensitivity. Color discrimination becomes more difficult in later life making it difficult to distinguish between blue and green shades under low light conditions. With older age the eye becomes more vulnerable to glare and takes longer time to recover after exposure to glare (i.e. car headlights at
Infants:
Newborns have uncoordinated and poor saccadic eye movement. it isn't till 6 months that fixation is effective and the lens accommodation is close to adult levels. The rods are adult-like in newborns, but the cones are much thicker and can't absorb as much light. Only with maturity do cones become narrower and longer travelling to form fovea. All this leads to better acuity and color vision in the first six months of life. The acuity and contrast sensitivity, ability to see distinguish varied size objects, is very poor in newborns. For instance, at birth acuity is around 20/400 to 20/800 and by 6 months it's …show more content…
The cornea, goes through minor changes such as increase in cornea thickness and curvature increasing the possibility of astigmatism. Aging also results in reduction of pupil size, number of rods, and retinal ganglion cells. Changes in eye movements are also prominent in old age with a decline in smooth pursuit eye movement (ability of eyes to closely follow a object) and saccadic eye movement (rapid movement of eyes that abruptly change fixation point). Fixation stability appears to have little effect on aging adults. They are able to maintain stable gaze for long time. Other noticeable changes as a result of age related decline are difficulty in performing under dim illumination due to a decline in the dark-adapted sensitivity. Color discrimination becomes more difficult in later life making it difficult to distinguish between blue and green shades under low light conditions. With older age the eye becomes more vulnerable to glare and takes longer time to recover after exposure to glare (i.e. car headlights at