A 7 2 Y E A R O L D L A W Y E R
w h o i s p u r s u i n g
h i s p a s s i o n f o r
p h o t o g r a p h y i n
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globally and referred to as “age-related” because it is rarely seen in individuals younger than 60 years old. With people living longer and longer, it is estimated that by 2040, there will be 300 million individuals with AMD throughout the world. And besides the blurred vision that this patient was experiencing, other patients often complain about difficulty recognizing familiar faces; straight lines that appear wavy; dark, empty areas or blind spots; and a general loss of central vision, which is necessary for driving, reading, and recognizing faces. Besides age, smoking is a universally agreed upon risk factor for AMD; hypertension and high blood lipids have been identified in some studies but not others. Prominent factors leading to development of AMD are genetic defects, particularly ones that code for proteins in what is called the complement cascade—a part of the innate immune system, the body’s first line of defense against bacteria and other invaders. The complement cascade is activated by signals or molecular signatures that stimulate pattern recognition receptors, suggesting the presence of an invader. While the complement system’s hair-trigger response rapidly fights invaders, preventing their growth and spread, it can also lead to false alarms when activated in the absence of an invader, resulting in damage to normal cells. To mitigate this liability, the body has developed systems to turn off the complement cascade. Some of the genetic variants that predispose one to AMD disable one or more of these fail-safe systems. “I’ve worked hard my entire life, and now that I’m finally able to do something I really enjoy, AMD is ruining it,” my patient said, clearly frustrated. “If I’ve had genetic defects my entire life that never bothered me, why are they causing trouble now?” I explained that the wear and tear of aging exposes cells’
suddenly unable to take sharp, well-focused photographs. An examination of each eye revealed yellow spots in the macula, the central area of the retina responsible for sharp vision. The macula in the right eye was thickened and raised in height , substantially reducing and distorting his vision. A test called a fluorescein angiogram, in which fluorescent dye is injected into an arm vein that travels to blood vessels in the retina for imaging, revealed a spot of intense fluorescence that enlarged over time, indicating the presence of abnormal blood vessels leaking plasma into surrounding tissue. An optical coherence tomography scan provided a two- dimensional optical cross section showing fluid beneath and within the right eye’s macula. The patient had a condition known as age-related macular degeneration (AMD), common to about 200 million individuals “ I ’ m s o r r y , b u t L A S I K o r a p r e s c r i p t i o n f o r g l a s s e s w o u l d h av e n o e f f ect o n A M D . B ot h s i m p ly c h a n g e t h e f o c u s
o n t h e r e t i n a . I f t h e r e t i n a i s d i s e a s e d , n e i t h e r a p p r oac h ca n i m p r ov e v i s i o n . ”
22 DANA FOUNDATION CEREBRUM | Spr ing 2021
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