Scan Acquisition Protocols
Stratus OCT User Manual PN 2660021134133 A
4-10
Concentric 3 Rings
The Concentric 3 Rings protocol consists of three equally spaced concentric circle scans
with radii in the ratio of 1:2:3. Like other circle scan patterns, this protocol is designed for
use around the optic disc to measure nerve fiber layer thickness. You can use it to build
custom scans. The default radii of the three circles are 0.9 mm, 1.81 mm and 2.71 mm. The
scans proceed from smallest to largest. You can adjust the radius for each of the three
circles, which can render the 1:2:3 ratio invalid. Note that when you change the radius of
the first or second circle, the radius of the second or third circle reverts its predefined value
of 1.81 or 2.71 mm.
• Note: Since you can adjust the placement of the second and thir
d scans, it is
possible to render the circles non-concentric.
Nerve Head Circle
•The Nerve Head Circle protocol enables you to acquire a single circle scan around the
optic disc. The default pattern has an aiming circle of diameter 1.5 mm (“Radius 1"),
and a scanning circle of diameter 3.4 mm (“Radius 2"). You can adjust both Radius 1
and Radius 2. This general-purpose protocol enables you to tailor a single circle to
examine RNFL thickness. It can be used to build custom scans.
Optic Disc
•The Optic Disc pattern is a 4 mm version of the radial lines pattern. It consists of a
series of 6 to 24 equally spaced line scans through a common central axis. The
diameter of the aiming circle (and thus line length) is fixed at 4 mm. The number of
lines is adjustable until you save the first scan in the series. It is designed exclusively
to examine the optic disc for indications of glaucoma. The scans you create with it are
for use with the Optic Nerve Head analysis protocol (see page 6-23).
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