Zeiss HUMPHREY 720i User Manual - page 122

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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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