Today we are going to discuss about the common eyesight problems Myopia and Hypermetropia .Myopia is most commonly know as Nearsightedness or short sightedness and Hypermetroia is also known as long-sightedness .These are the common disorders in which light does not focus on the retina of the eye . In the recent years number of cases related to myopia and Hypermetropia has increased. Both these are curable and can be corrected by using prescription glasses or contact lenses . To cure it permanently one can undergo laser eye surgeries .
Myopia and Hypermetropia
Here we are going to discuss some of the major differences between these two types of eyesight problems . Both are refractive defects in vision .( What is refractive error ) The formation of object’s images take place at different positions in both cases . Different type of lenses are prescribed for Long sightedness and short sightedness .Taking about the nature of these problems or defects both are almost opposite in nature to each other . Here we will explain you both defects with problem diagram and how image formation take place in both cases .
Hypermetropic eye concept
# Result of defect
In case of myopia , a person is not able to see distant objects clearly while in hypermetropia , one can’t clearly see the nearby objects.
# Location of Image Formation
In Myopia , light from a distant object forms an image before it reaches the retina.It can be because the eye is too long, or the cornea/ crystalline lens is too strong While in second case ,the image of a nearby object is formed behind the retina. It may be due to the reason that eye is too short, or the cornea/ crystalline lens does not refract the light enough.
# Cause of defect
Possible causes for Myopia are reduction in focal length of the eye lens or elongation of eye ball . Causes for Hypermetropia include either increase in focal length of the eye lens or flattening of the eyeball .
# Correction lenses used
In both cases different correction lenses of suitable focal length are used . For myopia we use concave lens ( Minus Powered ). The purpose of this lens is when it is placed in front of myopic eye, it moves the image back to the retina thus clarify the image. For Hypermetropia convex lens ( Plus Powered ) are used . Convex lens move the image forward and focuses correctly on the retina.