U Assessment

HISTORY. Changes in vision go unnoticed for a long time because of the slow progression. Patients frequently complain of problems with reading and night driving. Ask if the patient is color blind, has always worn glasses or contacts, has a history of cataracts, or is under the treatment of an eye doctor or optometrist. Generally, patients with cataracts report decreasing visual acuity with painless, increasingly blurred vision; visual distortion such as glare, dazzling effects, or dimness; or decrease in color perception and discoloration brought about by changes in lens color to yellow, amber, and finally to brown. The presence of other risk factors, such as trauma, radiation exposure, metabolic disorders, eye infection, and medication history, is important. Ascertain if the patient's mother contracted German measles, mumps, or hepatitis during pregnancy.

PHYSICAL EXAMINATION. Cataract formation causes blurred vision, a loss measured by use of the Snellen chart. Color perception of blue, green, and purple is reported as varying shades of gray. If the cataract is advanced, shining a penlight on the pupil reveals the white area behind the pupil. A dark area in the normally homogeneous red reflex confirms the diagnosis.

PSYCHOSOCIAL. Because the loss of vision is usually gradual, the patient may deny visual dysfunction until it affects the actions of daily life, reading, or driving. Anxiety and fear of losing one's eyesight are common emotional responses. Social isolation may also occur because visual difficulties impede easy movement away from the home and because of possible embarrassment caused by impaired vision.

Diagnostic Highlights

General Comments: No specific laboratory tests identify cataracts. Diagnosis is made by history, visual acuity test, and direct ophthalmoscopic exam.

Test

Normal Result

Abnormality with Condition

Explanation

Ophthalmoscopy or slit lamp examination

Normal conjunctiva, cornea, crystalline lens, iris, sclera

May reveal a dark area in the red reflex.

Microscopic instrument that allows detailed visualization of anterior segment of eye to identify lens opacities and other eye abnormalities

198 Cataract

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