Welch Allyn 18200 Manual Del Usuario página 9

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4. Interpretation of Results
A) Hyperopia
1. Hyperopia exists when, at the 2/3 meter distance using the
plano mirror effect, "with" motion is neutralized using a
plus lens greater than +1.50 diopters and both meridians
neutralize with the same strength lens.
2. Total hyperopia is estimated by subtracting 1.50 diopters
from the total strength lens used. For example, if it takes a
+2.50 lens to neutralize motion at 2/3 meter, the total
hyperopic error is +1.00 diopter.
B) Myopia
1. Myopia exists under several circumstances.
a) When "with" motion, using the plano mirror effect at 2/3
meter, is neutralized with a plus lens of less than 1.50
diopter strength. (When motion is neutralized with
exactly a 1.50 diopter lens, the eye is emmetropic.)
b) When at 2/3 meter, using the plano mirror effect, no
motion appears at all. In other words, when the motion
is neutralized with no lens in the refracting apparatus.
The myopia is then exactly 1.50 diopters.
c) When the motion is "against" using the plano mirror
effect, and is neutralized with a minus lens.
C) Astigmatism
1. Astigmatism exists when the two principal meridians
neutralize with different strength lenses. It may be present
in many forms.
a) Simple hyperopic;
b) Simple myopic;
c) Compound hyperopic;
d) Compound myopic;
e) In the mixed form
(one meridian hyperopic and the opposite one myopic).
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