WHAT IS THE DIFFERENCE BETWEEN PRESBYOPIA AND ASTIGMATISM?

 

Astigmatism is an error in the visual approach because the cornea, rather than being spherical, is slightly oval. This refractive error is described in function of the difference of curvatures and the orientation or axis of the same. People who have astigmatism may have trouble seeing from near and far.

Astigmata are usually myopic and / or hyperopic. An astigmata may have visual problems similar to those experienced by a presbyopic. But, it should be noted that while astigmatism is determined by the genetic morphology of the eye, presbyopia is due to stiffness of the lens, caused by the passage of time .

WHAT IS THE DIFFERENCE BETWEEN PRESBYOPIA AND MYOPIA?

The myopia or refractive error is a mistake in the visual approach which occurs when the distance between the cornea and the retina is too long. Thus, the image perceived by the eyes is “formed” before reaching the retina and, as a consequence, the myopic has difficulty seeing the objects that are far, but not those that are near.

The greater the degree of myopia, the more the person has to approach the objects to see them well. Presbyopia is also a refractive error but it is not due to the genetic morphology of the eye, but to the malfunctioning of the eye due to age. On the other hand, presbyopes have difficulty seeing nearby objects, not distant ones. In addition, while myopia usually appears in childhood and evolves to stabilize (around 20 years), presbyopia appears after 40 years.