Sorsby's fundus dystrophy (SFD) is a very rare genetic disorder characterized by the loss of central vision.

[4] Patients typically become symptomatic in their 40s due to loss of central vision.

[1] However, tests of rod photoreceptor function (i.e., night vision tests) show dysfunction at an earlier age.

One of the most sensitive visual function parameters for early SFD is a prolongation of rod-mediated dark adaptation.

[5][6] High-resolution structural imaging of the Bruch's membrane and of the underlying choriocapillaris – the capillary plexus nourishing the outer retina – also shows early alterations.