Myopia is the most common ametropia. It presents with blurry distance vision.
Myopia usually has very characteristic signs and symptoms.
The classical symptoms of myopia include include the following:
The signs of myopia include the following:
The diagnostic interventions include:
Myopia can be congenital or acquired. The anatomical changes contributing in the etiology of myopia include the following :
Increase in axial length of the eye
The myopic eyeball is enlarged. The axial length of the eyeball, therefore, enhances. The light rays entering the eye fall short and the image fails to form on the retina and forms, instead, at some point proximal to the retina, resulting in blurring of vision.
The curvature is increased which causes abnormal refraction of the light rays entering the eye and hence, the image fails to form on retina.
Abnormal refractive index of the lens
Change in the refractive index of the lens, as in nuclear sclerosis, can lead to myopia.
The lens may be displaced anteriorly, resulting in abnormal focusing of the light rays.
Children and old people are affected more. A familial tendency to myopia has been found. A lot of factors affect the prevalence of myopia including, age, sex, race and occupation.
As the light rays enter the eye of myopic person, they undergo abnormal refraction due to changes in the refractive power of various refractive media in the eye, i.e. the cornea or lens. The axial length of eye is also increased. Due to the combination of these factors, the light rays focus at a point proximal to retina and hence, image forms before the retina. The resultant image of the distant objects, is therefore, blurred.
Degenerative changes in the sclera also contribute in the development of myopia. Due to these changes, the sclera fails to withstand the normal intraocular pressure. Further changes in the retina and choroid include the following:
Myopia, also commonly known as short sightedness or near sightedness, refers to the inability of eye to focus the incoming light of rays on the retina when the accommodative power of the eye is at rest. Hence a myopic person faces difficulty seeing the far objects. The near objects, however, can be clearly visualized.
Myopia is a common refractive error that is prevalent in people beyond 40 years of age. Mild degree of myopia is called “low myopia” whereas a higher degree of myopia is commonly called ‘high myopia”.
Myopia is he condition in which the individual is unable to visualize the far objects properly. He can see near objects perfectly. Various changes in the structure of the eyeball lead to this condition. If myopia is of low level, it can be corrected by regular use of glasses and contact lenses. If myopia is too high, surgical methods can be used for the correction of this condition. With proper care, myopia can be prevented in the early age.