
48
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 .5 .3
P attern Dev iation
Pattern Deviation values remove the effect of overall shifts in sensitivity to better expose the
pattern of any field loss.
At the end of a test the software calculates, for each test location, the
values
(the differences between the test result and that of an age-matched normal). To then derive the
Pattern Deviation values it offsets the Total Deviation values according to the overall height of
the patient's hill of vision. If the patient has a less sensitive eye than that of an age-matched
normal (maybe they have some media opacities) then the Pattern Deviation values will be lower
than the Total Deviation values.
The offset is calculated from an analysis of the most sensitive regions of the visual field and has
a maximum amplitude of 6dB in either direction.
When there is a particularly large amount of visual field loss, the Pattern Deviation calculations
become inaccurate and are not displayed.
The Pattern Deviation values are presented in two different forms:
Absolute values in decibels (dB).
Symbols representing the probability that the threshold measure comes from a normal
eye. The probability values take into account the variability in threshold estimates at
each test location.
Th e a b o ve f i g u r e s h o w s t h e To t a l D e vi a t i o n (l e f t ) a n d Pa t t e r n D e vi a t i o n (r i g h t )
va l u e s a s s e e n i n t h e s t a n d a r d p r i n t o u t . Ab s o l u t e va l u e s a t t h e t o p a n d
p r o b a b i l i t y s ymb o l s b e l o w .
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Содержание Henson 9000
Страница 1: ...Elektron Eye Technology Ltd Henson 9000 ...
Страница 49: ...49 Visual field tests E l e k t r o n E ye Te c h n o l o g y 2 0 1 8 ...
Страница 85: ...85 Options program E l e k t r o n E ye Te c h n o l o g y 2 0 1 8 ...
Страница 123: ...123 Appendix 3 Installation E l e k t r o n E ye Te c h n o l o g y 2 0 1 8 ...
Страница 124: ...124 Henson 9000 Perimeter User Manual E l e k t r o n E ye Te c h n o l o g y 2 0 1 8 ...
Страница 131: ...131 Appendix 4 Maintenance and warranty E l e k t r o n E ye Te c h n o l o g y 2 0 1 8 ...
Страница 152: ......