Abnormal macular pigment distribution in type 2 idiopathic macular telangiectasia

Purpose: To determine the distribution of macular pigment in type 2 idiopathic macular telangiectasia (IMT). Methods: Twenty-two eyes of 12 patients with type 2 IMT were examined by means of best-corrected visual acuity testing, fundus biomicroscopy, fundus photography, fluorescein angiography, and optical coherence tomography. Macular pigment optical density (MPOD) was assessed using a modified confocal scanning laser ophthalmoscope whereby MPOD was calculated from fundus autofluorescence images acquired at two different excitation wavelengths (488 and 514 nm). The results were verified with a method that provides density maps after digital subtraction of log fundus reflectance maps (four patients) and by means of heterochromatic flicker photometry (four patients). Results: MOPD distribution showed an abnormal pattern for all patients with type 2 IMT. In correspondence to the late-phase hyperfluorescent areas shown by fluorescein angiography, MPOD was reduced in the macular area, while there was preserved MPOD at 5 degrees to 7 degrees eccentricity. Conclusions: The central depletion of macular pigment represents a novel phenotypic characteristic of type 2 IMT. Recording of macular pigment distribution may prove useful in the diagnosis of type 2 IMT and implicates an impaired trafficking or storage of lutein and zeaxanthin in the disease process.