Which of the following is not a cause of hypermetropia: September 2009
Ans. D: Anterior dislocation of the lens Factors responsible for hypermetropia: Sho axial length of the eyeball Curvature hypermetropia commonly occurs as a factor in astigmatism (corneal plana) Index hypermetropia accounts for the hypermetropia of old age due to increased refractive index of the coex of the lens relative to the nucleus so that overall refractive power of the lens decreases. It may be associated with diabetes, tumors, microphthalmia (a growth dysfunction during fetus development) and fovea hypoplasia, a condition that affects the blood vessels in the retina. While these conditions may result in hypermetropia, one of the most commonly cited causes of farsightedness is considered to be aging.
Sho axial length of the eyeball
Flat cornea
Increased refractive index of the coex of lens
Anterior dislocation of the lens