Elektron Technology HENSON 8000, User Manual

Page: 45 / 159

45 Visual field tests
© 2017 Elektron Technology
3 .2 .3 .1 Me a n De fe ct
The Mean Defect score (w hich is given on the printout) gives the clinician an
estimate of the extent of damage.
A more negative value indicates a less sensitive eye. Mean Defect values are
sensitive to both scotomata and media opacities. The value w ill go dow n if a
patient has a glaucomatous field defect and if they have a cataract.
As the name implies, the Mean Defect score is based on the average of all the
defect values, excluding those from the blind spot area. How ever, as some
test locations are more variable than others, it is w eighted to give more
importance to the less variable locations (those nearer the centre of the tested
field).
A P-value is given w hen the probability of the MD value coming from a normal
patient is below 10% (possible outputs are <10%; <5%; <2%; <1%; <0.5%).
When it is above 10% then the message
W ith in N o rma l L imits w ill be displayed.
T he f ig ur e a b o v e s ho ws the g lo b a l ind ic e s a s a p p e a r o n the s ta nd a r d p r int
o ut.
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