Near-sightedness (Myopia)
Patients with myopia see near objects clearly, but can not see distant objects very clearly.
There are three types of myopia:
Length Related Myopia:
In length related myopia, the eye is generally longer compared to a normal eye.
The focus point is located in front of the retina.
Distant objects are seen blurry.
As the length of the eye increases, myopia increases and thus blurred vision increases. Optic correction is provided by reducing the refractive power of the eye.
Thus the focal point shifts behind the retina.
Curvature Related Myopia:
In this case, the size of the eye is normal, but excessive curving of the lens or cornea causes light beams to focus in front of the retina.
Myopia related with refraction:
Hardening of the eye lens (cataract), which occurs in advanced ages, may increase the refractive index. In these cases, patients may state that they can read better due to myopia.
In patients with diabetes, high glucose content in the intraocular fluid may lead to increased refraction inside the eye. In this case, a transient myopia occurs. The eyes should be examined when blood glucose levels return to normal in these patients.