Alpha Omega Alpha Honor Medical Society

2010 Research Abstract

Relationship Between Drusen Accumulation and Cone Structure in a Patient with Dry Age-Related Macular Degeneration

Investigator: Katrina Woo, New York Medical College and the Department of Ophthalmology, University of California, San Francisco, School of Medicine
Co-investigator: A. Roorda, School of Optometry, University of California, Berkeley
Mentor: Jacque L. Duncan, Department of Ophthalmology, University of California, San Francisco, School of Medicine

Purpose: To study the effects of drusen accumulation on cone photoreceptors in a subject with dry age-related macular degeneration (AMD).

Methods: Adaptive optics scanning laser ophthalmoscopy (AOSLO) and spectral domain optical coherence tomography (SD-OCT) were used to image macular cones in a subject with AMD at two time points (at baseline and 2-years later) and compared with normal values. Digital color fundus photography and infrared and autofluorescent fundus photos were obtained. Visual acuity (VA) and color vision were also measured. Coding sequences of the complement factor H (CFH) gene were bidirectionally sequenced in the subject with AMD.

Results: Molecular analysis revealed homozygous risk factor polymorphisms in the CFH gene (CC at rs2274700 and CC rs1061170) in a 64 year-old man with dry AMD. Numerous drusen were present in the macula. VA was 20/16, and color vision was normal. SDOCT showed macular drusen as elevations beneath the RPE-segment outer junction with protrusion into the photoreceptor outer segment and outer nuclear layer. In the subject with AMD, AOSLO showed contiguous patches of cones interspersed with areas where cone structure was poorly resolved. Localized increases in cone spacing were seen in areas overlying drusen and between drusen, when compared with 9 age-similar normal subjects aged 50-79. In areas directly overlying drusen, there was a decrease in the number of regions with normal cone spacing over 2 years.

Conclusions: AOSLO revealed increased cone spacing in macular areas directly overlying drusen, suggesting the cytotoxic effects of lipofuscin deposits are associated with localized cone loss.

Updated on June 8, 2011.

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