There are a number of common conditions that are likely to affect our vision throughout adulthood. However, when properly diagnosed and treated, there is no reason that these conditions should lead to life-long vision loss.

Refractive errors affect the way light is bent and focused within the eye. A normal, well-rounded eyeball admits light rays through the cornea and focuses that light onto the retina, which transmits images to the brain. Most refractive errors can be successfully treated with prescription eyeglasses or contact lenses.

Myopia, commonly called "nearsightedness," occurs when a flattened or elongated eyeball causes light reflected from distant objects to be focused somewhere in front of the retina, instead of directly on the retinal surface.

Hyperopia is the opposite of myopia. The eyeball is too short causing light rays from near objects to be focused somewhere behind the retina.

Presbyopia refers to a loss of elasticity in the lens of the eye. This may hinder your ability to shift focus between near and distant objects. Everyone is likely to experience this: lens flexibility starts decreasing in youth and usually begins to interfere with vision around age 40 - when one's arms are said to get too short!

Astigmatism occurs when the front surface of the eye has an irregular curvature. This causes images to be imprecisely focused. People with astigmatism may notice occasional distortion and blurring of images at all distances.

Other eye disorders interfere with light entering the eye. These disorders include clouding, scarring and other obstruction of the lens as well as degenerative conditions that affect the tissue inside the eyeball. These disorders generally require medication or surgery.

Cataracts are cloudy or discolored areas of the lens of the eye. Like trying to see through a dirty window, cataracts impede sight by blocking portions of the field of vision. Cataracts can result from disease, poor nutrition, trauma, drugs or medications, increasing age and/or genetic tendencies.

Glaucoma is a group of diseases often associated with increased pressure within the eye that results in damage to the optic nerve and subsequent loss of vision in a characteristic manner. Glaucoma is especially dangerous, since it is generally asymptomatic until the disease is relatively advanced since loss of vision usually occurs first in the periphery of the visual field.

Macular degeneration refers to deterioration of the central area of the retina, where light rays are focused to form an image. Macular degeneration often causes "blind spots" within the central field of vision and spares the peripheral vision (the opposite of glaucoma).