Figure 1.

Small optic discs in Down syndrome. (A) Small optic disc with vascular tortuosity in a child with Down syndrome. This image exemplifies the formula used in the estimation of the disc-to-macula distance (DM) to disc diameter (DD) ratio (DM/DD): Dfx2+ D₁/D₁+ D₂ (38, 39)_. Both vertical and horizontal disc diameters were considered, to compensate for oval discs. (B) Small, round optic disc with a double ring sign between the black arrows. (C) Hypoplastic disc of a child with Down syndrome. Papillary vascular malformation is evident. A large halo of peripapillary atrophy is seen at 360° (white arrows). The gray arrow indicates an area of pigmented epithelium hypertrophy at the temporal margin of the disc. (D) Small tilted optic disc in a child with Down syndrome and myopia. A scleral crescent is visible at the temporal margin (between the black arrows). The disc is oval and bean-shaped in this case, with a hyperpigmented halo. An extensive area of peripapillary atrophy, with visible choroidal vessels, is evident (white arrows).