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Table 1 Definition of retinal areas

From: Grading fluorescein angiograms in malarial retinopathy

Retinal area Definition
Macula A circle centred on the centre of the fovea with a radius of 2.5 ETDRS disc diameters, or 3.8 mm [23]
The nasal edge is approximately in contact with the temporal border of the optic disc
Fovea A circle centred on the centre of the fovea with a diameter of 1/3 disc diameter, or ~0.5 mm
Zone 1 (inner periphery) The area between the macula and a circle extending 1 disc-fovea distance from the edge of the macula (Fig. 1, red-circle)
Zone 2 (mid periphery) The area between the circle defining the extent of the inner periphery and a circle extending two disc-fovea distances from the edge of the macula (Fig. 2, blue circle)
Zone 3 (far periphery) All retina beyond the extent of the mid periphery (Fig. 2, beyond the blue circle)
  1. Retinal areas are defined in terms of quadrants centred on the fovea, and concentric rings at increasing distance from the fovea. Distances are given in terms of retinal landmarks, such as proportions of optic disc diameter, and the distance from the disc to the fovea