A person
looking at a person wearing a shirt with a pattern comprising
vertical and horizontal lines is able to see the vertical lines more
distinctly than the horizontal ones. What is this defect due to? How
is such a defect of vision corrected?
A person looking at a person wearing a shirt with a pattern comprising vertical and horizontal lines is able to see the vertical lines more distinctly than the horizontal ones. What is this defect due to? How is such a defect of vision corrected?
In the
given case, the person is able to see vertical lines more distinctly
than horizontal lines. This means that the refracting system (cornea
and eye-lens) of the eye is not working in the same way in different
planes. This defect is called astigmatism. The person’s eye has
enough curvature in the vertical plane. However, the curvature in the
horizontal plane is insufficient. Hence, sharp images of the vertical
lines are formed on the retina, but horizontal lines appear blurred.
This defect can be corrected by using cylindrical lenses.
In the given case, the person is able to see vertical lines more distinctly than horizontal lines. This means that the refracting system (cornea and eye-lens) of the eye is not working in the same way in different planes. This defect is called astigmatism. The person’s eye has enough curvature in the vertical plane. However, the curvature in the horizontal plane is insufficient. Hence, sharp images of the vertical lines are formed on the retina, but horizontal lines appear blurred. This defect can be corrected by using cylindrical lenses.
