SETTING-UP TESTS
3-19
REV. B 02/03 PN 51680-1
HUMPHREY FIELD ANALYZER
II -
i
series
All patients requiring near vision correction should use trial lenses while taking
central field
tests
and the
central portion of full field tests
. For your convenience, the HFA II automati-
cally calculates the proper trial lens for your patient, if you know the patient’s distance
prescription and date of birth (refer to “Entering Patient Data” earlier in this section).
If you are not using the automatic trial lens calculation, refer to the following guidelines for
selecting trial lenses.
GUIDELINES FOR TRIAL LENS SELECTION:
1.
Ignore cylinders of 0.25 D or less.
2.
For cylinder errors up to 1.25 D use the spherical equivalent. Use the full
cylinder correction for cylinder errors of 1.50 D or more.
3.
Refer to Table 3.4 to determine the spherical power to be used.
Table 3.4: Spherical Trial Lens Correction for Central Visual Field Testing
Distance
Distance
Distance
Distance
Distance
Distance
Distance
Distance
Distance
Rx Greater
Rx Equals
Rx is:
Rx is:
Rx is:
Rx is:
Rx is:
Rx is:
Rx is:
than Zero
Zero (Plano)
-0.50
-1.00
-1.50
-2.00
-2.50
-3.00
> -3.00
Age
Spherical Trial Lens to Be Used
Use Hyperopic
Myopic
Under 30
Distance Rx
•
•
•
•
•
•
•
Dist. Rx + 3.25
30 to 39
Dist. Rx + 1.00
+1.00
+0.50
•
•
•
•
•
Dist. Rx + 3.25
40 to 44
Dist. Rx + 1.50
+1.50
+1.00
+0.50
•
•
•
•
Dist. Rx + 3.25
45 to 49
Dist. Rx + 2.00
+2.00
+1.50
+1.00
+0.50
•
•
•
Dist. Rx + 3.25
50 to 54
Dist. Rx + 2.50
+2.50
+2.00
+1.50
+1.00
+0.50
•
•
Dist. Rx + 3.25
55 to 59
Dist. Rx + 3.00
+3.00
+2.50
+2.00
+1.50
+1.00
+0.50
•
Dist. Rx + 3.25
60 and over
Dist. Rx + 3.25
+3.25
+2.75
+2.25
+1.75
+1.25
+0.75
•
Dist. Rx + 3.25
•
means no spherical trial lens needed
The following are examples of trial lens corrections using Table 3.4:
Example A.
For an emmetropic (plano) 70 year-old patient, follow the Distance Rx Equals Zero (Plano)
column to the 60 & Over row. The trial lens correction for this patient is +3.25 D.
USING TRIAL LENSES
3.htp
3/14/03, 3:08 PM
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Содержание HUMPHREY 720i
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