Dr. Grandinetti is a senior clinicalresearch pharmacist at the NationalCancer Institute, National Institutesof Health, Rockville, Maryland. Theviews expressed are those of theauthor and not those of any governmentagency.
The World Health Organizationestimates that 37 million peopleare blind, with almost 82% ofthem aged 50 years or older.1,2 Cataractcauses almost half of blindness globallyand occurs more frequently in developingcountries.3 Women are at a slightlygreater risk than men, with an estimatedfemale-to-male ratio of 1.5 to 2.2.
Cloudy or opaque cataracts on thelens of the eye are generally caused by adenaturing of crystallins, the major lensprotein.4 In cataracts, less light reachesthe retina, impairing vision and decreasingquality of life. Three subtypes, definedby clinical appearance and location, arenuclear, cortical, and posterior subcapsular(PSC) cataracts. Each has different symptomsand risk factors and occurs at differentrates in different populations.1,5-10
The most common cause is aging, butatopic diseases and their treatments, diabetes,trauma, and congenital disorderscan cause cataracts, too. Some drugs,such as those causing photosensitivity,and radiation therapy are associatedwith cataract formation.11 Several studieshave associated long-term corticosteroiduse (at prednisone doses of ≥10-15mg/day) with PSC formation.12-16 Thisassociation is stronger with oral steroidsthan with inhaled steroid use, and childrenappear to be particularly at risk.7Cataracts may progress even after stoppingthe corticosteroid. Clinicians shouldorder comprehensive eye exams morefrequently in individuals with predisposingrisk factors.
Surgery is the only treatment optionand should be considered when thecataract impairs the patient's ability tofunction in daily life.17 Cataract surgeryhas a 95% or better success rate inhealthy eyes. It involves removing thelens and replacing it with an intraocularlens. During surgery, adequate pupil dilationmust be maintained to remove thecrystalline lens and implant the correctiveintraocular lens without causingtrauma to the iris. Prostaglandin releasecan cause surgically induced miosis andincrease the risk of postoperative surgicalcomplications.
Alpha1 adrenoceptor blockers canincrease the likelihood of surgical complicationsby causing the pupil to suddenlyconstrict during the operation.5Discontinuing the drug before surgeryhas not yet been evaluated; however,planned measures, such as iris hooks,iris dilator rings, or viscoelastic devices,can minimize the potential complications.18 Topical nonsteroidal anti-inflammatorydrugs (NSAIDs) are often usedto inhibit surgically induced miosis.19
Although postsurgical complicationsare infrequent, patients are often startedon topical antibiotic, corticosteroid, andNSAID drops to prevent complications.9,17
Early diagnosis and treatment ofendophthalmitis, a serious eye infection,is critical to prevent vision loss. Empirictherapy is based on the suspectedmicroorganism most likely encounteredduring surgery, from the patient's conjunctiva,eyelids, or nose. The most commonmicroorganisms are gram-positiveStaphylococcus aureus and Staphylococcusepidermidis. Gram-negative infectionswith Pseudomonas spp andPropionbacterium acnes occur less frequently.The treatment includes intravitrealinjections of vancomycin and ceftazidimeor amikacin (for patients sensitiveto beta lactams). Another treatmentoption is broad-spectrum oral fourth generationfluoroquinolones. Thepatients are often treated prophylacticallybefore surgery with topical povidoneiodineor topical, subconjunctival, systemic,or intracameral antibiotics.20,21
Cystoid macular edema (CME), fluidaccumulation in the central retina, is themost frequent cause of vision loss. It usuallyoccurs 4 to 6 weeks after surgery,and symptoms include blurred or decliningcentral vision and painless retinalinflammation and swelling. Vision loss isusually temporary. Clinicians should suspectCME in any patient with worse-than-expected vision after surgery.19Most patients experience some postoperativeinflammation. If left untreated,inflammation may cause discomfort, delayrecovery, decrease vision, and lead toother complications.22
Combination therapy with a topicalNSAID and/or corticosteroid is indicatedfor documented CME and inflammation.CME treatment starts 1 week before surgeryand continues for at least 4 weeks,up to several months after surgery. Whentreating inflammation, NSAIDs are generallystarted 24 hours after surgery andcontinued for up to 14 days (Table).Topical steroids are generally administeredfor 2 to 6 weeks after surgery.19,22
Most adverse events following topicalNSAIDs are local, such as burning, stinging,conjunctivitis, atonic mydriasis, andlocal anesthetic effects, as well as pruritus,erythema, and edema of the bulbarconjunctiva and lids. Systemic reactionsoccur rarely. Increased intraocular pressureand delayed wound healing areassociated with topical corticosteroids.NSAIDs are useful alternatives for patientswho develop increased intraocularpressure while using topical steroids.19
Pharmacists treating cataract patientsshould use their clinical expertise tomonitor appropriate medication use—especially nursing and patient adherenceto the medication regimen—and promoteappropriate follow-up care androutine eye examinations.