Fundus Autofluorescence in Type 2 Idiopathic Macular Telangiectasia: Correlation with Optical Coherence Tomography and Microperimetry

PurposeTo use multiple imaging methods to investigate patients with type 2 idiopathic macular telangiectasia (IMT) at different disease severity stages so as to characterize and categorize disease progression through the full spectrum of disease phenotypes.DesignObservational case series.MethodsTwelve patients with type 2 IMT (22 eyes) examined with fundus photography, angiography, optical coherence tomography imaging, fundus autofluorescence (FAF), and microperimetry testing in an institutional setting.ResultsEyes examined by multiple imaging methods were classified into 5 proposed categories (0 through 4): category 0 (fellow) eyes had normal results on all imaging methods. Category 1 eyes had increased foveal autofluorescence on FAF imaging as the only imaging abnormality. Category 2 eyes had increased foveal autofluorescence together with funduscopic and angiographic features typical of type 2 IMT. Category 3 eyes had additional evidence of foveal atrophy on optical coherence tomography, and category 4 eyes had all the above features plus clinically evident pigment clumping. FAF signal increased in intensity in the foveal region from category 0 through category 3, whereas category 4 eyes demonstrated a mixed pattern of increased and decreased FAF signal.ConclusionsThe findings here outline a sequence of progressive changes seen with multiple imaging methods in advancing stages of disease. Increase in foveal autofluorescence is an early anatomic change in type 2 IMT that may precede typical clinical and angiographic changes. Loss of macular pigment density in the fovea and a changing composition of fluorophores in the retinal pigment epithelium may underlie these changes on FAF in the fundus.