AS we grow older, our chances of developingeye disease increase dramatically.Age-related macular degeneration (AMD)is the leading cause of vision loss in peopleover the age of 50 in the western world.This progressive disease threatensmore patients than cataracts and glaucomacombined. According to the AmericanMacular Degeneration Foundation, 10 millionpeople in the United States are alreadyaffected. As the baby-boomer generationcomes of age, it is anticipated that thosefigures will double in the next 25 years.Though statistics on AMD in CostaRica are unavailable, Dr. Lihteh Wu, a retinaspecialist and president of the CostaRica Ophthalmology Association, says hesees an average of 10 patients with AMD –approximately a third of whom are NorthAmericans – per week.Born in Taiwan, Wu, 40, came here asan infant and considers Costa Rica home.After high school, he went to the UnitedStates for college, then studied and trainedthere for 15 years at various universitiesand medical centers, including the MountSinai Medical Center in New York and theGlaser-Retina Center in Maryland.Wu says that thanks to Costa Rica’shigh medical standards, foreign residentsand visitors can find qualified ophthalmologistshere – especially at private facilities– who studied in the United States orEurope and who speak English.FOR some time, it was believed thatmacular degeneration was more commonlyfound in people with fair complexions andlight eyes.“When I returned toCosta Rica from the UnitedStates six years ago, I discoveredAMD in darkerskinnedindividuals aswell,” recalls Wu, who isalso a member of theAmerican Society of RetinaSpecialists and a diplomatof the American Board ofOphthalmology. “In Asia,especially in Japan, the diseaseis also quite present.The only group exceptedwould be black people.”AMD is little known orunderstood. It is caused bythe painless deterioration ofthe central portion of theretina, known as the macula.“Think of the eye as a camera,” Wusays. “In this camera, the retina would bethe roll of film onto which all the light isfocused, sending the information to thebrain via the optic nerve. The macula itselfis a yellow-pigmented area on the centralretina, containing color-sensitive rods andthe center of sharpest vision.”When the macula is damaged, the areaof focus appears blurry or distorted, or thepatient sees either a white or dark spot, Wuexplains. The condition rarely causes totalblindness, but it can affect one’s ability todrive, read, recognize faces or colors, orperform detailed work.“What causes AMD is not conclusivelyknown,” the expert says. “Age and geneticsare believed to be primary factors. Inaddition, most studies indicate there is asubstantial link between macular degenerationand smoking.”Exposure to sunlight is also thought tobe a factor, and those who suffer from highblood pressure and elevated cholesterollevels could be at greater risk.THE disease comes in two forms,“wet” and “dry,” with the latter affectingapproximately 90% of the afflicted. Withdry AMD, the deterioration of the retina isassociated with the formation of deposits,known as drusen. This phenomenon leadsto thinning and drying out of the macula.Symptoms include blurred vision, needingmore light to read, and difficulty recognizingfaces at a distance.“For some unknown reason, the maculaatrophies, but it’s a slow process, usuallybeginning in one eye and sometimesspreading to the other,” Wu explains. “Atpresent there is no known cure for AMD,and more research needs to be done.”In October 2001, the results of a long- term study conducted by the National EyeInstitute (NEI) of the United States confirmedthat high-potency antioxidants andzinc significantly reduce the progressionof dry AMD. Ophthalmologists now recommendbeginning this vitamin therapyimmediately upon diagnosis.Several brands, such as OcuvitePreserVision, ICaps and Viteyes, can bepurchased via the Internet from the UnitedStates. Unfortunately, these dietary supplementsare not available in Costa Rica, Wusays. He adds that patients – especiallycurrent smokers or smokers who have quitwithin the last five years – should discussthe use of such supplements with theirfamily doctor to avoid side effects.Only 10-15% of AMD patients developthe wet form of the disease, in whichabnormal blood vessels leak fluid beneaththe macula, moving it from its originalposition.“Wet AMD causes severe loss ofvision in a matter of days or weeks,” Wusays. “Initial symptoms are the same as indry macular degeneration, and early treatmentis vital to preserve as much vision aspossible.”PHOTODYNAMIC therapy (PDT) isa non-invasive, state-of-the-art treatmentthat may be helpful in early stages of wetAMD. Visudyne, a light-sensitive drug, isinjected into the arm, and the drug is thenactivated by a cold laser.“The new laser therapy causes lessdamage to the tissue and seals the unwantedblood vessels in the eye to prevent furtherleakage,” Wu explains, adding that anaverage of three to five procedures per eyeover a period of two years may be neededto stop vision loss.Wu says Visudyne is an expensivedrug, and each PDT treatment costs$2,500-3,000. In Costa Rica, PDT is notcovered by the Social Security System(Caja); patients must contact their individualor personal insurance advisor.“Another new drug called Macugenwas recently approved by the U.S. FederalDrug Administration,” Wu says. “Theabnormal growth of blood vessels underthe macula is controlled by a moleculecalled vascular endothelial growth factor(VEGF). Macugen is an anti-VEGF drug,and it is the first to act directly against thecausing agent.”Wu says the drug is administered rightinto the eye as a painless injection. Theresults are a little better than with photodynamictherapy, but in most cases theinjection has to be repeated every sixweeks. Because it is an intraocular injection,the treatment involves a small risk ofcomplications such as infection, retinaldetachment and inflammation.THE American Macular DegenerationFoundation recommends everyone overthe age of 45 or with a family history ofretinal problems such as AMD have his orher eyes checked periodically. Also, a coupleof times a week, cover one eye at atime and focus on the lines of a graph orcalendar; if they look wavy or blurred, seea doctor immediately. For more information,visit the foundation’s Web site atwww.macular.org.Wu can be reached at Clínica deCirugía Ocular in San José, Calle 28,Avenida 2, 100 meters south of Pizza Huton Paseo Colón, across from Sala Garbo.Call 256-2134 or 256-2159, or e-maillw65@cornell.edu.
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