you have device that is capable of performing automated perimetry
Picking a test
CP30-2 means: - Central - central portion of the visual field - Pattern - uses a designed pattern - 30 = 30 degrees from fixation - -2 = means alternate points of the grid (as opposed to -1)
What does the -2 mean? - Paurush says that the -2 means -2 degrees in the horizontal and vertical meridians that are not tested.
When interpreting fields, consider: - altitudinal field defects - hemianopia - So by removing the 2 degrees, then you prevent false positives
- see the gaps
ChatGPT 
How to interpret
First assess adequacy
Fixation losses: - how many times lose fixation False positive errors - seeing a signal when there is no signal False negative error - denying a signal when previously have recognised one there
What does the false negative mean? / it means they have failed to detect a stimulus when they have previously detected a stimulus OF A LOWER STIMILUS/brightness.
Then assess the fields themselves
Now, this clearly reveals that the tail is the nasal aspect: 
The blindspot is the ONH, and hence the tail must be nasal
When reading fields, Niemandt said: - put the left left, and the right right
![FD1DD1D0-682C-42BF-AAD3-9577A5CCBD8A.jpg] (FD1DD1D0-682C-42BF-AAD3-9577A5CCBD8A.jpg) - here the presents the decibels.
The total deviation is the difference between this patient’s decibal signals and the AGE ADJUSTED / STANDARDISED decibel
The issue with the total deviation is that it doesn’t discriminate neurological vs overt field loss.
For example, a vitreous haemorrhage can cause a field loss. A bad cataract as well etc.
So what is pattern deviation? Supposedly proprietary algorithm that attempts to remove the “noise” from the fields. It tries to give a pattern that would make sense with the hill of vision.
GHT = glaucoma hemifield test = superior vs inferior hemifield (specific to glaucoma)
VF24-2 =visual field index. Interprets pattern of glaucomatous field loss??
MD24-2 =22 mean deviation in decibels from patient to age standardised (mean of the total deviation decibel)
PSD24-2 =deviation from age adjusted normal.
That line at the bottom is the gaze tracker.
How does it test fixation loss? - it shines a light in your blind spot and if you register it, then you’re not fixated.
References
https://eyeguru.org/essentials/visual-fields/ https://eyerounds.org/tutorials/VF-testing/#gsc.tab=0