MORPHOLOGY OF EARLY CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION - CORRELATION WITH ACTIVITY

The purpose of this study was to describe the morphology of early chor oidal neovascularisation (CNV) and compare the findings in two patient s, in the first of whom the vessels appeared inactive and in the secon d progressive. Changes common to both included a diffuse deposition of membrane coils external to the basement membrane (BsM) of the retinal pigment epithelium (RPE), and macrophages and foreign body giant cell s beneath thinned segments of Bruch's membrane (BrM). In the first pat ient small activated vessels surrounded by enlarged pericytes were fou nd in the choroid beneath these areas and pursued a convoluted course, bulging into or through BrM, but without spreading in the sub-RPE spa ce. This choroidal phase of CNV may be common and unrecognised. In the second patient there was spread of CNV in the sub-RPE space with extr avasation of red cells and fibrin. The tips leaking fibrin were covere d by a thick BsM-like material and naked endothelial cells were not se en. Pericytes were absent here but were observed at the non-leaking ed ge. The difference in activity of CNV in the two patients appeared to correlate with the quantity of membranous debris present.