Scholl GB, Song H-S, Winkler DE, Wray SH . The pattern visual evoked potential and pattern electroretinogram in drusen-associated optic neuropathy. Arch Ophthalmol 1992;110:75–81.
Before the advent of OCT ... where blurring of disc margins, nerve fiber layer edema with loss of transparency, or peripapillary hemorrhages are all suggestive of optic nerve edema.