Sir,

Skarmoutsos and Kyle have made a good point regarding the comparison of the superior and inferior venous filling in this case. The venous filling does appear to be at the same stage in the upper and lower systems. There is trilaminar flow just visible at both of the first main bifurcations of the superior and inferior hemiretinal veins. Trilaminar flow occurs at the junction of two veins with bilaminar flow, with the inner laminar of each vein joining to produce three laminae.1 If this is a cilioretinal artery, it would have fluoresced along with the choroid 1–3 s before the central retinal artery, and in theory the venous stage would then start 1–3 s early in the superior venous system with more fluorescence present than in the picture shown.

The patient in this case had the FFA performed for unrelated reasons, and unfortunately this was the earliest frame available. Earlier frames of the fundus fluorescein angiogram would have been conclusive to identify this as a cilioretinal artery, and without these there is no definitive answer. The cilioretinal artery was an incidental finding, and we felt that it was inappropriate to repeat the FFA just for personal gain.