Idiopathic macular telangiectasia type 2: distribution of macular pigment and functional investigations.

Purpose: Analysis and categorization of macular pigment (MP) distribution in type 2 idiopathic macular telangiectasia (IMT2) with regard to a possible grading scale for the severity of the disease.

Methods: Nineteen IMT2 patients were examined including visual acuity (VA), fundus biomicroscopy, fluorescein angiography (FLA), microperimetry and optical coherence tomography (OCT). Distribution of MP was analyzed and categorized in MP density maps calculated from autofluorescence images obtained at 488 and 514 nm excitation wavelengths.

Results: Typical features in MP density maps are in class I (n=8), a triangular segment of reduced MP in the temporal fovea and central accumulation of MP, class II (n=12), further expansion of the segment and vanishing of central accumulation, and class III (n=18), oval effacement of MP centrally, surrounding halo of MP at 5-7 degrees eccentricity. These classes were associated with the stages of the disease and increasing restrictions in visual function.

Conclusion: Association between changes in MP distribution, stages of IMT2 and restrictions in visual functions suggests that the classification of MP patterns reflects a severity scale for IMT2. Degenerative processes causing impairments in transport and storage of lutein (L) and zeaxanthin (Z) leading to secondary vascular changes may play a causative role in the disease.