Abstract
Purpose:
Retinal angiomatus proliferation (RAP) is a form of wet age related macular degeneration (AMD) in which occult choroidal neovasuclarization is associated with intraretinal microvascular proliferation in the paramacular area. The purpose of our study is to describe the optical coherence tomography (OCT) findings of the retina preceding the development of intraretinal and subertinal edema.
Methods:
We reviewed spectral domain OCT images of six eyes of five patients with dry AMD who had macular OCT images prior to the conversion to wet AMD with RAP lesions. Macular cube images were taken using a Topcon 3D-OCT 2000, Zeiss Cirrus OCT or Heidelberg Spectralis OCT. OCT images of the RAP lesions and prior OCT images, up to three years, were reviewed to detect any changes in the retina, retinal pigment epithelium (RPE) or choroid at the site of future RAP lesions.
Results:
We observed that structural changes in the retina appear months to years before the appearance of typical RAP lesions. One of the earliest signs is elevation of the RPE either in the form of a small pigment epithelial detachment (PED) or more often in the form of RPE irregularity with underlying moderate hyperreflectivity consistent with fibrovascular tissue. At this point ellipsoid zone (EZ) band may be intact or disrupted. Another early sign is the presence of one or more intense intraretinal hyperreflective foci in the outer nuclear layer (ONL) or outer plexiform layer (OPL) near the peak of the RPE elevation. At this time, the ONL becomes thin or interrupted; the OPL may also become thin. Another sign, which may appear later, is blending of the RPE elevation with the OPL. Other retinal layers often remain relatively intact.
Conclusions:
Reviewing OCT images showed that retinal structural changes are evident months to years before the appearance of typical RAP lesions. The earliest changes are visible at the RPE level, suggesting that this cell may be the origin of the disease.
Keywords: 412 age-related macular degeneration •
453 choroid: neovascularization •
700 retinal neovascularization