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) |