Essilor Instruments VISION-R 700, User Manual

Page: 62 / 128

On the touch screen of the console, by clicking once on the setting value of the particular eye.
(*)
If the variation step in the cylinder power was chosen at a value other than 0.25 D, the automatic
adjustment of the sphere power will also occur after two variation steps in the cylinder.
For example: if the pitch is 1.00 D, the sphere value will be corrected by +1.00 D after a change in
cylinder power of -2.00 D.
Bi-ocular balance
Objective
Adjust the equilibrium of corrections between the right and left eye in a bi-ocular vision condition (both eyes
open but simultaneously perceiving different targets).
Principle
The principle of the test is to slightly blur the patient’s vision by introducing a power of +0.50 D (or +0.75 D) in
front of both eyes to make it easier to compare the vision of the right eye and the left eye.
It is easier to compare two fuzzy visions to two sharp ones.
If the patient sees more clearly with one eye than with the other, blur the eye that sees the best, increasing the
power by +0.25 D so as to obtain a blurred vision balance between the two eyes.
Once the equilibrium has been achieved, remove the previously introduced +0.50 D (or +0.75 D) power and
retain the power, if any, added on one of the two eyes.
Note
The practice of bi-ocular equilibrium testing assumes that the visual acuity of both eyes is identical or similar.
In the case of significantly different visual acuities between the right and left eye, a polarized red/green test or a
vertical prism dissociation test should be used. It will allow the patient to simultaneously take a different
red/green test for each eye. It will then be possible to simultaneously search for red/green equality for each eye,
with both eyes open.
U
SER MANUAL
> P
ERFORMANCE OF TESTS DURING A REFRACTION EXAMINATION
Vision-R 700 - Essilor automatic phoropter > V1 - 09-2020 62