cataract /kat″ərakt/ [Gk, katarrhakies, waterfall] , an abnormal progressive condition of the lens of the eye, characterized by loss of transparency. A yellow, brown, or white opacity can be observed within the lens, behind the pupil. Most cataracts are caused by degenerative changes, often occurring after 50 years of age. The tendency to develop cataracts is inherited. Trauma, such as a puncture wound, may result in cataract formation. Less often, exposure to such poisons as dinitrophenol or naphthalene causes them. Congenital cataracts are usually hereditary but may be caused by viral infection during the first trimester of gestation. If cataracts are untreated, sight is eventually lost. At onset, vision is blurred; then bright lights glare diffusely, and distortion and double vision may develop. Uncomplicated cataracts of old age (senile cataracts) are usually treated with excision of the lens and either surgical insertion of an intraocular lens or prescription of special contact lenses or glasses. The soft cataracts of children and young adults may be either incised and drained or fragmented by ultrasound. See also congenital cataract, senile cataract. ▪ OBSERVATIONS: Symptoms of cataracts include progressive, painless blurring and distortion of objects, glare from bright lights, and gradual loss of vision. Signs include a yellow, brown, or white coloring on the pupil and myopia. The crystalline lens of the eye becomes cloudy and opaque. Cataracts are identified by a complete ophthalmoscopic examination, including funduscopy and slit lamp examination. The primary complication is blindness. ▪ INTERVENTIONS: Surgical removal of the lens is the primary treatment and is performed only after vision becomes compromised. Follow-up laser surgery is frequently needed to remove a secondary membrane that can form. Topical antiinfective drugs and mydriatic-cycloplegics are used preoperatively, and corticosteroids, antibiotics, and mydriatics are used postoperatively. Corrective lenses may be used to correct vision, and strong lighting may be used to enhance vision until surgery is performed. ▪ PATIENT CARE CONSIDERATIONS: Before surgery, care is focused on assessment and attention to self-care deficits related to decreasing vision. Preoperative care includes education about the surgical experience and lens implants and reduction of anxiety about impending surgery. Postoperative education focuses on proper use and instillation of eyedrops, prevention of infection, and activity restrictions. Recovery is usually rapid, and most individuals are able to resume activities of daily living within a week.
