Plaque Offset Window

A plaque is assumed to touch the external sclera at the center of its concave facial surface, with its central axis directed towards the center of the eye. The plaque offset window allows you to offset and/or angularly wobble a plaque away from this assumed orientation. The default offset and angular wobble are all zero.

From the Setup Window click the Offset button

to open the Plaque Offset window.

OffsetBtn

In most situations you will want the 3D axes to be displayed in the eye reference frame in which the origin is located at the center of the eye. When wobbling a plaque, it is useful to display axes in the plaque reference frame while rotating the plaque. The Eye and Plaque buttons switch the axes reference frame between the eye reference frame and the plaque reference frame.

Default
IllustrationNone

When the offset and angular wobble are all zero, the plaque will touch the external sclera at the center of its concave surface, with its central axis pointing towards the center of the eye.

None
IllustrationOblique

To model an oblique muscle (e.g. superior oblique) passing between the plaque face and sclera, apply a 1 mm offset from the sclera per COMS requirement 12.2.6.

Oblique
IllustrationOblate

To model suturing a plaque anteriorly on an eye whose anterior hemisphere is oblate, adjust the plaque's attitude by applying an angular "wobble" with respect to the default orientation until the suture eyelets touch the anterior sclera. If the plaque face is spherical, the posterior portion of the plaque will lift away from the sclera.

Oblate