Topcon Compu-Vision CV-5000 User Manual

105
5. OPERATION FOR TESTS
5.3.8 SHEARD'S CRITERIA
Sheard's criteria is a theory that, to keep normal binocular func-
tion, the extra convergence or divergence that is twice as large
as heterophoria or more is necessary.
In this test, check if the patient has extra convergence or diver-
gence that meets Sheard's criteria according to the measured
heterophoria.
If there is extra convergence or divergence that meets Sheard's
criteria, it is judged that prism prescription is not necessary.
If this isn’t the case, the program calculates the prism quantity
that makes up for the insufficiency automatically.
1 Prepare for the test.
This test must be executed after the horizontal phoria has already been measured.
Before this test, measure horizontal phoria.
For the horizontal phoria test, refer to "5.2.4 HORIZONTAL PHORIA MEASURE-
MENT (PRISM SEPARATION)" on P.86.
2 Click the [Sheard] button.
While the phoria test is being executed, the [Sheard] button is displayed as a function
button.
This [Sheard] button is valid when horizontal phoria is measured. After the horizontal
phoria has been measured, click this button.
To perform the near-point test, select the test chart icon shown below.
Far-point
chart
Far-point test chart icon Near-point
chart
Near-point test chart icon
ACP-8(A)
This test is conducted at
near only.
NC-3(E)
In far-point test, the chart where the characters are arranged on one vertical line or the
visual acuity chart to which the vertical mask is applied is set.
In near-point test, set a proper target from the near-point card targets manually.
Hetero-
phoria
Eye line
Extra con-
vergence

Topcon Compu-Vision CV-5000 Specifications

General

Brand	Topcon
Model	Compu-Vision CV-5000
Category	Medical Equipment
Language	English