DETAILED CHARACTERIZATION OF CHOROIDAL MORPHOLOGIC AND VASCULAR FEATURES IN AGE-RELATED MACULAR DEGENERATION AND POLYPOIDAL CHOROIDAL VASCULOPATHY.
OBJECTIVE
To characterize and compare morphologic and vascular features of the choroid in patients with typical age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) and to determine if PCV subtypes can be identified based on these choroidal features.


METHODS
Choroidal features of patients with AMD and PCV recruited from the prospectively planned Asian AMD Phenotyping Study were analyzed. Patients underwent choroidal imaging using spectral-domain optical coherence tomography with enhanced depth imaging. Raw optical coherence tomographic images were loaded on a custom-written application on MATLAB that enabled delineation for detailed morphologic and vascular analyses, including the curvature of the choroid-sclera interface, number of inflection points, choroidal thickness and choroidal vascular area within the macular (6 mm centered on fovea) and foveal (1.5 mm centered on fovea) regions. An inflection point represents the contour of the choroid-sclera interface, with >1 point signaling irregular shape.


RESULTS
A total of 156 eyes of 156 patients (78 affected eyes of 78 patients with typical AMD and 78 affected eyes of 78 patients with PCV) were analyzed. Eyes with PCV had thicker baseline choroidal thickness and greater choroidal vascular area compared with those with typical AMD (P < 0.05); these differences were no longer significant after adjusting for age and hypertension (P > 0.05). Typical PCV subtype with choroidal thickness of ≥257 μm had significantly greater choroidal vascular area at macular (mean difference = 0.054 mm; P < 0.001) and foveal (mean difference = 0.199 mm; P < 0.001) regions compared with eyes with typical AMD. However, eyes with PCV without thick choroid had similar choroidal vascular area as eyes with typical AMD.


CONCLUSIONS
Based on the choroidal vascular features, two subtypes of PCV can be classified: typical PCV with increased choroid vascularity and polypoidal choroidal neovascularization with low choroidal vascularity. These data provide further understanding of different AMD and PCV subtypes.
Singapore Eye Research Institute and Singapore National Eye Centre, Vitreo-Retinal Department, Singapore.|Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore.
Preeti
P
Gupta
Singapore Eye Research Institute and Singapore National Eye Centre, Vitreo-Retinal Department, Singapore.|Duke-NUS Medical School, Singapore.
Daniel Shu Wei
DSW
Ting
Singapore Eye Research Institute and Singapore National Eye Centre, Vitreo-Retinal Department, Singapore.|Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore.
Sri Gowtham
SG
Thakku
Singapore Eye Research Institute and Singapore National Eye Centre, Vitreo-Retinal Department, Singapore.|Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore.|Duke-NUS Medical School, Singapore.
Tien-Yin
TY
Wong
Singapore Eye Research Institute and Singapore National Eye Centre, Vitreo-Retinal Department, Singapore.|Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore.|Duke-NUS Medical School, Singapore.
Ching-Yu
CY
Cheng
Singapore Eye Research Institute and Singapore National Eye Centre, Vitreo-Retinal Department, Singapore.
Edmund
E
Wong
Singapore Eye Research Institute and Singapore National Eye Centre, Vitreo-Retinal Department, Singapore.|Duke-NUS Medical School, Singapore.
Ranjana
R
Mathur
Singapore Eye Research Institute and Singapore National Eye Centre, Vitreo-Retinal Department, Singapore.
Doric
D
Wong
Singapore Eye Research Institute and Singapore National Eye Centre, Vitreo-Retinal Department, Singapore.|Duke-NUS Medical School, Singapore.
Ian
I
Yeo
Singapore Eye Research Institute and Singapore National Eye Centre, Vitreo-Retinal Department, Singapore.|Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore.|Duke-NUS Medical School, Singapore.
Chui Ming
CM
Gemmy Cheung
D000368:Aged; D002829:Choroid / Q000098:blood supply* / Q000473:pathology; D015862:Choroid Diseases / Q000175:diagnosis*; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005500:Follow-Up Studies; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D011127:Polyps / Q000175:diagnosis*; D011446:Prospective Studies; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000379:methods*; D014792:Visual Acuity; D057135:Wet Macular Degeneration / Q000175:diagnosis*