Myopia Types

The eye problem in which near objects are seen clearly but distant objects are blurred is called as Short-sightedness or Myopia. It can be corrected by wearing minus power (concave) glasses or lenses. Myopia can be

	*Axial myopia* -length of the eyeball is more than normal.
	*Curvature myopia* -curvature of the refractive surfaces, through which light has to pass before it focuses on the retina, is more than normal. Therefore light focuses in front instead of on the retina.
	*Index myopia* -due to change in refractive index of the eye media.

It can start as -

	Hereditary
	School age myopia -begins at usually 6-8 years and progresses gradually during the student years.
	Old age myopia - comes on gradually from 55-70 years, called `second sight`. Occurs due to increase in density of the lens, due to aging.

Grades -

	Mild-less than –4.0 Dsp. correction
	Moderate-between -4.0 to –9.0dsph. correction
	Very high –above –9.0dsph correction.

Short-sightedness ( Myopia)

Grades -