Cone structure in subjects with known genetic relative risk for AMD.

Kimberly Stepien // Publications // Aug 01 2014

PubMed ID: 25014365

Author(s): Land ME, Cooper RF, Young J, Berg E, Kitchner T, Xiang Q, Szabo A, Ivacic LC, Stepien KE, Page CD, Carroll J, Connor T Jr, Brilliant M. Cone structure in subjects with known genetic relative risk for AMD. Optom Vis Sci. 2014 Aug;91(8):939-49. doi: 10.1097/OPX.0000000000000323. PMID 25014365

Journal: Optometry And Vision Science : Official Publication Of The American Academy Of Optometry, Volume 91, Issue 8, Aug 2014

PURPOSE Utilize high-resolution imaging to examine retinal anatomy in patients with known genetic relative risk (RR) for developing age-related macular degeneration (AMD).

METHODS Forty asymptomatic subjects were recruited (9 men, 31 women; age range, 51 to 69 years; mean age, 61.4 years). Comprehensive eye examination, fundus photography, and high-resolution retinal imaging using spectral domain optical coherence tomography and adaptive optics were performed on each patient. Genetic RR scores were developed using an age-independent algorithm. Adaptive optics scanning light ophthalmoscope images were acquired in the macula extending to 10 degrees temporal and superior from fixation and were used to calculate cone density in up to 35 locations for each subject.

RESULTS Relative risk was not significantly predictive of fundus grade (p = 0.98). Only patients with a high RR displayed drusen on Cirrus or Bioptigen OCT. Compared to an eye with a grade of 0, an eye with a fundus grade equal to or greater than 1 had a 12% decrease in density (p < 0.0001) and a 5% increase in spacing (p = 0.0014). No association between genetic RR and either cone density (p = 0.435) or spacing (p = 0.538) was found. Three distinct adaptive optics scanning light ophthalmoscope phenotypical variations of photoreceptor appearance were noted in patients with grade 1 to 3 fundi. These included variable reflectivity of photoreceptors, decreased waveguiding, and altered photoreceptor mosaic overlying drusen.

CONCLUSIONS Our data demonstrate the potential of multimodal assessment in the understanding of early anatomical changes associated with AMD. Adaptive optics scanning light ophthalmoscope imaging reveals a decrease in photoreceptor density and increased spacing in patients with grade 1 to 3 fundi, as well as a spectrum of photoreceptor changes, ranging from variability in reflectivity to decreased density. Future longitudinal studies are needed in genetically characterized subjects to assess the significance of these findings with respect to the development and progression of AMD.