The treatment of age-related macular degeneration (AMD), the leading cause of blindness in
the developed world, is undergoing a revolution. Intraocular injections of medications that
can shut down the rapidly destructive "wet" form of the disease have changed this form to a
chronic illness. However, vision is still lost. For the early forms of AMD, progression to
the advanced "wet" and "dry" forms and severe vision loss is impeded but not stopped by
current therapies of oral antioxidants. Thus, a better understanding of early AMD is needed
to discover its root causes and provide treatment before irreparable damage is done.
The most important, highest-risk, and least understood form of early AMD is "reticular
macular disease" (RMD). RMD is associated with significant progression to advanced AMD, both
wet and dry. The lesions of RMD are well seen on the advanced retinal imaging techniques of
spectral domain optical coherence tomography (SD-OCT) and scanning laser ophthalmoscopy
(SLO). On SLO, RMD presents a pox-like pattern of dark defects SD-OCT provides
high-resolution cross-sectional images of the retina, where RMD is seen as a collection of
cholesterol-containing deposits, and the choroid, an essential blood supply of the retina,
which is thinned and may be damaged in RMD. A unified explanation of these facets of RMD is
lacking.
Regarding AMD and systemic diseases, the association between stroke, heart attack and AMD has
been studied, but with some conflicting findings. For example, a relationship with heart
attack has been established in patients less than age 75, but not in older patients. Where
does RMD fit in? At present, no one knows. However, the known facts are these: RMD is
associated with decreased longevity, which is not the case with other early forms of AMD.
This could happen if RMD and systemic vascular disease co-exist. Finally, there is the very
high proportion of women relative to men among older patients with RMD, about 85%. Women
develop heart disease later than men and survive heart disease a decade longer on average. It
is possible that these diseases both begin earlier in life, with more men dying before
reaching older ages and demonstrating RMD. The research team submitting this proposal has
preliminary data suggesting that this is in fact the case.
In a small group of subjects 50-75 years old, RMD was detected in a significant proportion of
those with CAD compared to those without. Furthermore, in this younger group, the ratio of
men to women in the RMD group was equal. The team proposes a large-scale initiative to
provide definitive answers to these questions, in collaboration with expert cardiologists and
neurologists to document vascular status unequivocally, and utilizing the most advanced
retinal imaging available for the detection of RMD. This could lead to greater understanding
of all three, stroke, heart attack and AMD, and ultimately better treatment, providing much
needed relief to suffering patients and relief to the healthcare burden of an aging
population.
