Table 1.

Definitions of optic disc parameters used

Hyperemia	Erythema of optic disc head in the absence of other signs of papilledema
Spontaneous venous pulsation	Pulsatility of the central retinal vein or branches seen within the disc head
Dilated retinal veins	Abnormally dilated retinal veins noted at the disc margin
Dilated pre-papillary capillaries	Visible dilated fine vessels on surface of optic disc
Blurred and elevated disc margin (by quadrant)	Elevation of optic disc rim with blurring of margin (by nasal, superior, temporal, inferior quadrant)
Disc hemorrhage	Any hemorrhage within disc head or within 1 disc diameter of disc margin. Most commonly splinter shaped
Cotton wool spot	Fluffy white lesion within disc head or retinal nerve fiber layer adjacent to the disc
Absent disc cup	Lack of central cup in optic disc