CONE DENSITY LOSS ON ADAPTIVE OPTICS IN EARLY MACULAR TELANGIECTASIA TYPE 2

Purpose: To determine whether cone photoreceptors are impaired early in macular telangiectasia type 2 (MacTel 2) progression. Methods: Eight patients with MacTel 2 lacking intraretinal cavitation underwent multimodal retinal imaging including adaptive optics. Cone packing metrics were determined in 5 sampling windows at different eccentricities from the fovea. Results were compared with a previously established normative database. Results: In MacTel 2 eyes, cone density was significantly lower than normal at all eccentricities (P < 0.0001). Mean cone spacing and mean percentage of hexagonally organized cone photoreceptors were respectively significantly larger and lower than normal at all eccentricities (P = 0.0488 and P < 0.0001). In MacTel 2 patients, adaptive optics showed an irregular patchy disturbance of the cone mosaic corresponding to some fragmentation of the interdigitation zone on optical coherence tomography. The ellipsoid zone remained intact in the studied area. Conclusion: Adaptive optics showed that the macular cone density was lower than normal even outside the telangiectasia in MacTel 2 lacking intraretinal cavitation, although the ellipsoid zone remained intact on optical coherence tomography. These findings do not indicate that the cone density loss is causative of the disease as it might be secondary to Müller cell or rod loss in this area. However, cone density assessment could become a useful parameter to monitor disease progression.