Abstract
Purpose: :
Type 2 idiopathic macular telangiectasia (IMT) is a complex disease involving telangiectasis of the parafoveal vasculature, foveal atrophy, retinal pigment epithelium (RPE) hyperplasia, and subretinal hemorrhage. As its pathogenesis is poorly understood, the use of multiple new techniques to evaluate macular structure and function may improve our understanding of the pathological changes in type 2 IMT.
Methods: :
Retrospective, cross-sectional study of 12 patients with type 2 IMT seen at the National Eye Institute (NEI) over a three-year period. In addition to conventional fundus photography and fluorescein angiography, optical coherence tomography (OCT) images, fundus autofluorescence (FAF), and microperimetry (MP) testing were obtained.
Results: :
Twenty-two eyes from 12 patients were classified into 5 staged categories based on systematic findings in parallel imaging studies. We have classified the eyes of these patients into five categories (0-4), each with a distinct constellation of findings obtained using a multiple modality approach. Category 0 eyes were unaffected, whereas the only abnormality seen in category 1 eyes was foveal hyperautofluorescence. Eyes in category 2 had fundoscopic and angiographic features of type 2 IMT along with foveal hyperautofluorescence. Additional features of category 3 and category 4 included foveal atrophy and pigment clumping, respectively. FAF hyperautofluorescence increased from category 1 through category 3, whereas category 4 eyes demonstrated a mixed pattern of hyperautofluorescence and hypoautofluorescence. Visual deficit in category 3 and category 4 eyes was related to the location of scotomata on MP testing.
Conclusions: :
Clinical characterization of type 2 IMT, a bilateral but sometimes asymmetric disease, can be improved with multiple modality clinical imaging. FAF imaging indicates foveal hyperautofluorescence as an early diagnostic change that precedes clinical signs and symptoms of type 2 IMT. Increasing FAF hyperautofluorescence and the emergence of FAF hypoautofluorescence with increasing disease severity suggest a primary role of the RPE in the initiation and progression of this disease.
Keywords: macula/fovea • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retinal pigment epithelium