Vision Changes Related to Cataracts
The hardening and yellowing of the lens caused by a cataract can result in the following vision changes that affect your daily functioning:
- Reduced ability to perceive contrast: Seeing an object clearly against a background of the same color—a white coffee mug on a light tablecloth, or a brown chair against a dark rug, for example—becomes more difficult and requires an increase in background contrast to make it "stand out."
- Reduced ability to perceive color: The lens gradually changes color, becoming yellowish or brownish, and is no longer clear or transparent. As a result, vision acquires a "brownish" tint, making it difficult to tell the difference between certain colors, such as navy blue, brown, and black; or blue, green and purple. This change in color can also degrade the sharpness of a person's vision.
- Problems with depth perception: Judging distances accurately—the height of a step or curb, or the depth of a bathtub, for example—requires closer attention. In addition, shadows and shadow patterns can be incorrectly interpreted as drop-offs, level changes, steps, or obstructions.
- Need for more light: As we get older, we generally need three to four times more light to perform everyday activities. Seeing clearly enough to read, write, sew, knit, or do home repairs usually requires a brighter, more focused light along with reading glasses or bifocals. This need for increased light occurs gradually, and most people are not aware that their lighting requirements may have changed over time.
- Increased sensitivity to glare: Although we need more light as we get older, too much light can also cause problems. Bright outdoor sunlight or reflected light from a hallway with highly polished floors can make it difficult to see clearly because too much light can also produce glare, which can interfere with seeing our surroundings clearly. People also tend to notice difficulty with night driving, due to glare from oncoming headlights.
- Overall blurring: People, objects, and colors look hazy, cloudy, and "washed out." This lack of detail makes it difficult to tell time, read, watch television, see food on a plate, and walk safely indoors and outdoors, since depth perception may also be affected. Some people with cataracts describe the effect as being similar to looking through a window that is hazy and streaked with dirt.