BRefractive errors

(1) Emmetropia—normal. Light focuses on the retina.

(2) Hypertropia—farsighted. Light focuses behind the retina and is corrected with a convex lens.

(3) Myopia—nearsighted. Light focuses in front of the retina and is corrected with a biconcave lens.

(4) Astigmatism. Curvature of the lens is not uniform and is corrected with a cylindric lens.

(5) Presbyopia is a result of loss of the accommodation power of the lens that occurs with aging. The near point (closest point on which one can focus by accommodation of the lens) moves farther from the eye and is corrected with a convex lens.

2. Layers of the retina (Figure 2-3)

Was this article helpful?

0 0
Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

Get My Free Ebook

Post a comment