What Is a Cataract?
A cataract is a lens opacity or cloudiness, one of the most common eye disorders. On inspection the lens looks gray or milky.
Classification
The three most common senile cataracts are defined by location in the lens. A nuclear cataract comes from central opacity and carries a strong genetic component. A cortical cataract involves the anterior, posterior, or equatorial cortex. A posterior subcapsular cataract sits in front of the posterior capsule.
Pathophysiology
Cataracts can develop in one or both eyes at any age. Risk factors include cigarette smoking, long-term corticosteroid use, sunlight and ionizing radiation, diabetes, obesity, and eye injuries. Recent studies also link cataract risk to lower income and education, smoking for 35 or more pack-years, and high triglyceride levels in men. Nuclear cataract is associated with myopia, which worsens as the cataract progresses. A dense cataract severely blurs vision, while one at the equator or periphery of the cortex does not block light through the center of the lens.
Statistics and Incidences
Cataract ranks behind only arthritis and heart disease as a leading cause of disability in older adults. It affects nearly 20.5 million Americans age 40 or older, about one in six people in that range. By 80 years of age, more than half of all Americans have a cataract or have had cataract surgery (National Eye Institute). The World Health Organization calls cataract the leading cause of blindness worldwide. Almost one in five people between 65 and 74 develop cataract severe enough to reduce vision.
Causes
Cataracts usually develop without an apparent cause, but can result from several sources. Senile cataracts develop in elderly patients from degenerative changes in lens proteins. Congenital cataracts occur in neonates from genetic defects or as a sequela of maternal infection during the first trimester. Traumatic cataracts follow a foreign body that injures the lens with enough force to let aqueous or vitreous humor enter the lens capsule and dislocate the lens. Complicated cataracts occur secondary to uveitis, glaucoma, or retinitis pigmentosa, or alongside systemic disease such as diabetes, hypoparathyroidism, or atopic dermatitis. Toxic cataracts result from drug or chemical toxicity (prednisone, ergot alkaloids, dinitrophenol, naphthalene, phenothiazines, or pilocarpine) or extended ultraviolet exposure.
Clinical Manifestations
Because all light entering the eye passes through the lens, any clouding worsens vision. Blurred vision is usually the first symptom. Glare is the pain felt looking directly into light. Halos appear as a lingering ring of light after looking away from a bright source. Double vision is another early sign.
Prevention
Teach the patient to quit smoking, one of the largest contributing factors, and to wear sunglasses to shield the eyes from the UV exposure that predisposes to cataract.
Complications
Complications after cataract surgery include retrobulbar hemorrhage (from retrobulbar infiltration of anesthetic if the short ciliary artery is hit by the injection), acute bacterial endophthalmitis (a devastating complication in about 1 in 1000 cases), and toxic anterior segment syndrome (noninfectious inflammation following anterior chamber surgery).
Assessment and Diagnostic Findings
Decreased visual acuity tracks directly with cataract density. The Snellen visual acuity test measures acuity. Ophthalmoscopy shows the extent of the cataract. Slit-lamp biomicroscopic examination establishes the degree of formation.
Medical Management
No nonsurgical treatment cures cataracts or prevents age-related ones.
Pharmacologic Therapy
Dilating drops are given every 10 minutes for 4 doses, starting at least 1 hour before surgery. Antibiotics may be given prophylactically against postoperative infection and inflammation. IV sedation eases anxiety and discomfort before surgery.
Surgical Management
Three procedures remove the cataract. Phacoemulsification removes part of the anterior capsule, then extracts the lens nucleus and cortex while leaving the posterior capsule and zonular support intact. Extracapsular cataract extraction (ECCE) removes the anterior lens and cortex, leaving the posterior capsule intact. Intracapsular cataract extraction removes the entire lens within its intact capsule.
After the lens is removed, three replacement options restore focus. Aphakic glasses magnify objects by 25%, making them appear closer than they are. Contact lenses give nearly normal vision but must be removed periodically, so the patient still needs a pair of aphakic glasses. IOL implants are the most common choice: the single-focus (monofocal) IOL cannot change shape, multifocal IOLs reduce the need for eyeglasses, and accommodative IOLs mimic the accommodation of a youthful, phakic eye.
Nursing Management
The cataract patient gets the usual preoperative care for ambulatory eye surgery.
Nursing Assessment
Assess recent medication intake; anticoagulants are commonly withheld to cut the risk of retrobulbar hemorrhage. Standard preoperative tests (complete blood count, electrocardiogram, urinalysis) are ordered only when the patient's history indicates them. Confirm stable vital signs before surgery. Review Snellen and other visual acuity test results, and use the medical history to determine which preoperative tests are needed.
Nursing Diagnosis
Common diagnoses include disturbed visual sensory perception related to altered sensory reception, risk for trauma related to poor vision and reduced hand-eye coordination, anxiety related to the threat of permanent loss of vision or independence, and deficient knowledge about coping with altered abilities.
Nursing Care Planning and Goals
Major goals: regain the usual level of cognition, recognize sensory needs, stay free of injury, identify environmental risk factors, keep anxiety at a manageable level, verbalize feelings of anxiety, and identify healthy ways to express it.
Nursing Interventions
Preoperatively, withhold anticoagulants to reduce the risk of retrobulbar hemorrhage. Postoperatively and before discharge, give the patient verbal and written instructions on protecting the eye, giving medications, recognizing signs of complications, and getting emergency care.
Evaluation
Confirm the patient meets the planned goals: usual cognition regained, sensory needs recognized, no injury, environmental risk factors identified, anxiety manageable and verbalized, and healthy coping expressed.
Discharge and Home Care Guidelines
Teach self-care before discharge, including activities to avoid. To prevent rubbing or poking the eye, the patient wears a protective eye patch for 24 hours after surgery, then eyeglasses during the day and a metal shield at night for 1 to 4 weeks. Expect slight morning discharge, some redness, and a scratchy feeling for a few days; a clean, damp washcloth can remove the discharge. Because cataract surgery raises the risk of retinal detachment, the patient must notify the surgeon for new floaters, flashing lights, decreased vision, pain, or increased redness.
Documentation Guidelines
Document individual findings (specific deficits, associated symptoms, and client and family perceptions), assistive device needs, use of safety equipment or procedures, environmental and safety concerns, level of anxiety with precipitating and aggravating factors, description and awareness of feelings, the plan of care, the teaching plan, client involvement and response to interventions and teaching, attainment of or progress toward outcomes, modifications to the plan of care, and long-term needs.
Frequently Asked Questions
What is a cataract? A cataract is a clouding of the eye's normally clear lens. Because all light entering the eye passes through the lens, that cloudiness scatters and blocks light and gradually blurs vision. On inspection the lens looks gray or milky (National Eye Institute).
How common are cataracts? Cataract affects nearly 20.5 million Americans age 40 and older, and by age 80 more than half of all Americans have a cataract or have already had cataract surgery. The World Health Organization names cataract the leading cause of blindness worldwide (National Eye Institute).
What are the first symptoms patients notice? Blurred vision is usually the first complaint. Patients also report glare and difficulty looking into bright light, halos around lights, fading or yellowing of colors, and trouble with night vision.
Can cataracts be treated without surgery? No. There is no medication or eye drop that cures a cataract or reverses age-related lens clouding. Surgery to remove the cloudy lens and replace it with an intraocular lens (IOL) is the only definitive treatment, and it is one of the most common and successful outpatient procedures.
What is the most important postoperative teaching? Protect the eye and watch for complications. The patient wears an eye shield, avoids rubbing or bumping the eye, and reports new floaters, flashing lights, decreased vision, increasing pain, or worsening redness right away, since these can signal retinal detachment or infection.
Why are anticoagulants often held before cataract surgery? Anticoagulants raise the risk of retrobulbar hemorrhage during the procedure, so they are commonly withheld per the surgeon's orders. Always confirm the patient's full medication list and recent intake during the preoperative assessment.