Abnormal Vessels

Retinal vessels do not typically cross the horizontal raphe. One rare physiological exception is a retinal macrovessel which is an enlarged single vessel (usually a vein), emerging from the optic nerve as usual but then diverting and crossing the horizontal raphe, perfusing a larger area of retina than typical vessels. They are predominantly unilateral and are usually benign findings, however occasionally serous retinal detachments, macular hemorrhage or foveal cystoid formation and reduced visual acuity may be associated with these vessels.

Retinal macrovessels however have do have an association with venous anomalies of the brain. Recent research has shown venous brain anomalies in 24% of people with unilateral retinal macrovessel compared with an incidence of between 0.2% and 6.0% in the normal population (Pichi et al. 2018). This led the authors to suggest systemic workup of patients with retinal macrovessels to include brain magnetic resonance imaging with contrast

A vortex vein varix is a physiological dilation of one of the choroidal vortex veins. It is a benign condition but may sometimes mimic a choroidal melanoma. OCT typically shows an optically empty thickening of the choroid with significant dilation of the choroidal veins.

During examination, a vortex vein varix can be most easily distinguished from a choroidal melanoma by observation with a binocular indirect ophthalmoscope. A vortex vein varix will typically flatten or collapse in certain directions of gaze and may be flattened with manual scleral indentation while a melanoma will not flatten.