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The prediction models for POAG require
the following:
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Age
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Vertical cup/disc ratio
by contour
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IOP (3 measurements per eye measured
using Goldmann applanation tonometry)
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Central corneal thickness
using an ultrasound pachymeter
(3 measurements per
eye)
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Pattern standard deviation using
any of the following (2
measurements per eye):
a. Humphrey
full threshold 30-2 or 24-2
b. SITA standard 30-2
or 24-2
c. Loss variance from Octopus 32-2
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Two
methods can be used to estimate the 5-year risk of developing
(POAG): a continuous method based on actual data and a simplified
point system. Please read the limitations
and cautions listed below.
For the Continuous Method:
You will enter actual
data for the patient age and eye measurements.
For the
Point System:
You will select the range for the patient
age and average of the multiple measurements.
Your results in using the two methods will be similar but
not identical. Please view the examples for each method
listed below.
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This calculator may be accessed via our website
by clicking the button above. You can download the calculator
to your computer by clicking the "Save
a copy " button in the pdf reader. |
This calculator may be accessed via our website
by clicking the button above. You can download the calculator
to your computer by clicking the "Save a copy " button
in the pdf reader. OR you may choose to print a copy of the
point system table to have available for use at any time. |
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The methods will
require the use of Adobe Reader, version 6.0 or higher.
A free download of the Adobe Reader is available on the Adobe website: |
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LIMITATIONS AND CAUTIONS
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The prediction
methods presented here are derived from two studies (OHTS
and EGPS) and should be useful to clinicians and patients.
There is no guarantee that the predicted risk is accurate
for individual patients.
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The predictions
are more likely to be accurate for patients who are similar
to the participants studied in the OHTS and the EGPS, and
if the testing protocols for your patients resemble those
used in these studies.
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These prediction models
were derived from studies on the development of early
POAG. It is not clear whether these models also predict
progression of established disease or the development
of visual disability.
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The following types of participants and methods of measurement were utilized in the OHTS and the EGPS:
- AGE: Age between 30 and 80 years.
A warning will be issued for ages greater than 80 or
less than 30.
- UNTREATED IOP:
IOP range 20-32 mm Hg. This is based on three measurements
per eye, both eyes, measured using Goldmann applanation
tonometry. A warning will be issued for values outside
20-32 mm Hg.
- CENTRAL CORNEAL THICKNESS: CCT
475-650 microns. Three measurements per eye, both eyes,
measured using ultrasonic pachymetry. A warning will
be issued for values outside 475-650 microns.
- VERTICAL CUP TO DISC RATIO:
One measurement per eye, both eyes. C/D ratio vertically
by contour, not by color.
- PATTERN STANDARD DEVIATION/CORRECTED LOSS VARIANCE: Two measurements per eye, both eyes, measured using either Humphrey or Octopus perimeters. Octopus Corrected Loss Variance measurements will be converted internally to Humphrey PSD equivalent.
THE PREDICTIONS DERIVED
USING THESE METHODS ARE DESIGNED
TO AID
BUT NOT TO REPLACE CLINICAL
JUDGMENT.
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