The fundoscopic view of the retina can be divided into 3 zones when describing the changes associated with retinopathy of prematurity (ROP).
The field of view in each eye is represented as a circle delimited by the ora serrata.
The right eye is scored in hours in a clockwise manner, with 12 o'clock indicating superior, 3 o'clock medial (nasal) and 9 o'clock lateral (temporal).
The left eye is scored in hours in a clockwise manner, but 9 o'clock is medial (nasal) and 3 o'clock lateral (temporal).
Zone I: a small circular area centered on the optic nerve and including the macula
Zone II: a larger circular area centered on Zone I. Its radius extends to the medial (nasal) margin of view. This zone does not extend to the lateral (temporal) margin of view.
Zone III: a circular area around Zone II, with Zone II located eccentrically. This enclosed a rim of retina of variable thickness, maximal laterally. It does not reach the nasal margin, but runs from 4 o'clock around to 2 o'clock for the right eye and from 10 o'clock to 8 o'clock for the left eye.
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