elektron eye technology Henson 9000, Manual, Page: 42 / 155

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Hens o n 9000 Per imeter Us er M a nua l
E l e k t r o n E y e T e c h n o l o g y 2 0 1 8
3 .2 .4 .1 M ean Def ec t
The Mean Defect value, 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
scotoma and media opacities. The value will go down if a patient has a glaucomatous field
defect and if they have a cataract.
The Mean Defect score is based on the average of all the defect values, excluding those
from the blind spot area. However, as some test locations are more variable than others, it is
weighted to give more importance to the less variable locations (those nearer the centre of the
tested field).
A P-value is given when 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 orm al L im its will be displayed.
Th e f i g u r e a b o ve s h o w s t h e g l o b a l i n d i ce s a s t h e y a p p e a r o n t h e s t a n d a r d p r i n t
o u t .
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