A cataract occurs when the clear lens of the eye becomes cloudy. Normally, light passes through the cornea (clear outer surface of the eye), through the pupil, then through the lens. The lens focuses light on the retina (the light sensitive tissue on the back of the eye), allowing a person to see clearly.
Cataracts obstruct this passage of light and thereby impair vision. If left untreated, an advanced cataract will result in blindness. Cataract is the leading cause of treatable blindness worldwide, and can be surgically corrected in about 15 minutes with $100 worth of resources. Most of the cataracts that we see in Honduras are very advanced (lenses ranging from deep amber to almost black in color).