ASSOCIATION OF DRUSEN VOLUME WITH CHOROIDAL PARAMETERS IN NONNEOVASCULAR AGE-RELATED MACULAR DEGENERATION.
OBJECTIVE
The choroid is thought to be relevant to the pathogenesis of nonneovascular age-related macular degeneration, but its role has not yet been fully defined. In this study, we evaluate the relationship between the extent of macular drusen and specific choroidal parameters, including thickness and intensity.


METHODS
Spectral domain optical coherence tomography images were collected from two distinct, independent cohorts with nonneovascular age-related macular degeneration: Amish (53 eyes of 34 subjects) and non-Amish (40 eyes from 26 subjects). All spectral domain optical coherence tomography scans were obtained using the Cirrus HD-OCT with a 512 × 128 macular cube (6 × 6 mm) protocol. The Cirrus advanced retinal pigment epithelium analysis tool was used to automatically compute drusen volume within 3 mm (DV3) and 5 mm (DV5) circles centered on the fovea. The inner and outer borders of the choroid were manually segmented, and the mean choroidal thickness and choroidal intensity (i.e., brightness) were calculated. The choroidal intensity was normalized against the vitreous and nerve fiber layer reflectivity. The correlation between DV and these choroidal parameters was assessed using Pearson and linear regression analysis.


RESULTS
A significant positive correlation was observed between normalized choroidal intensity and DV5 in the Amish (r = 0.42, P = 0.002) and non-Amish (r = 0.33, P = 0.03) cohorts. Also, DV3 showed a significant positive correlation with normalized choroidal intensity in both the groups (Amish: r = 0.30, P = 0.02; non-Amish: r = 0.32, P = 0.04). Choroidal thickness was negatively correlated with normalized choroidal intensity in both Amish (r = -0.71, P = 0.001) and non-Amish (r = -0.43, P = 0.01) groups. Normalized choroidal intensity was the most significant constant predictor of DV in both the Amish and non-Amish groups.


CONCLUSIONS
Choroidal intensity, but not choroidal thickness, seems to be associated with drusen volume in Amish and non-Amish populations. These observations suggest that choroidal parameters beyond thickness warrant further study in the setting of age-related macular degeneration.
*Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California; †Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California; ‡First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China; §Department of Epidemiology & Biostatistics, Case Western Reserve University, Cleveland, Ohio; ¶John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida; and **Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
Siva
S
Balasubramanian
Jianqin
J
Lei
Muneeswar G
MG
Nittala
Swetha B
SB
Velaga
Jonathan
J
Haines
Margaret A
MA
Pericak-Vance
Dwight
D
Stambolian
SriniVas R
SR
Sadda
D000368:Aged; D061365:Amish; D002829:Choroid / Q000473:pathology*; D005260:Female; D005431:Florida / Q000453:epidemiology; D005584:Fovea Centralis / Q000473:pathology*; D006801:Humans; D008297:Male; D009017:Morbidity / Q000639:trends; D010414:Pennsylvania / Q000453:epidemiology; D015593:Retinal Drusen / Q000175:diagnosis* / Q000208:ethnology / Q000209:etiology; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence / Q000379:methods*; D014792:Visual Acuity; D057135:Wet Macular Degeneration / Q000150:complications / Q000175:diagnosis* / Q000208:ethnology