Zeiss HUMPHREY 720i, User Manual

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7-6 STATPAC ANALYSIS & PRINTING RESULTS
REV. B 02/03 PN 51680-1 HUMPHREY FIELD ANALYZER II -
i
series
The glaucoma hemifield test On 24-2 and 30-2 tests taken using the SITA Standard, SITA Fast or Full Threshold strategies,
the Glaucoma Hemifield Test (GHT) evaluates five zones in the superior field and compares
these zones to their mirror image zones in the inferior field. The GHT evaluates the severity of
disturbed points in each zone pair, relative to its normative database, and prints one of these
messages: GHT WITHIN NORMAL LIMITS, OUTSIDE NORMAL LIMITS, or BORDERLINE. The
Glaucoma Hemifield Test is not available with tests using FastPac.
Figure 7.2: Superior Field Zones Used in the Glaucoma Hemifield Test
The primary aim of the GHT is to identify localized visual field loss occurring in a pattern
typical of that seen in glaucoma. It also indicates when test results show that the overall field is
severely depressed or shows suspiciously high sensitivity. The message GENERAL REDUCTION
OF SENSITIVITY is printed whenever the field is depressed to a level seen in fewer than 0.5% of
the normal population in the patient’s age bracket.
Similarly, when the comparison indicates abnormally high sensitivity (a level found in fewer
than 0.5% of the normal population of that age), the message ABNORMALLY HIGH SENSITIV-
ITY appears. The GHT does not flag the case where only a few points are abnormally high, but
it will catch cases where the overall pattern of patient responses indicates a patient who is
overly anxious to push the button. It is always useful to check the false positive and false
negative errors, and fixation losses as well.
Note: The GHT is not intended for use in patients being evaluated for diseases other than
glaucoma.
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