Questions- UFOF and field of BSV Flashcards
example UFOFs + qs in doc
Why is it important to use a moderate speed? What is the problem with moving the target too fast or too slow?
Too fast – will miss end point and reduce accuracy as field will be overestimated
Too slow – patient likely to lose concentration, test will take a long time, may be uncomfortable for patient
Why should you conduct the tests without glasses?
Glasses frame will be a barrier so may result in reduced field compared to what the patient can actually do. Prismatic effect from glasses when testing BEO
You remove the patient’s glasses for testing but they say they are unable to see the target – what do you do on Takagi? And on the arc perimeter?
Takagi – has a lens holder so can put in patient’s prescription
Arc – make target bigger / do with glasses if unavoidable but record this clearly on results
Why is it important to check the patient is not using their AHP during the test?
Reduces accuracy of field of BSV and UFOF
In field of BSV - will skew the position of the field of BSV. Need to know true position for management decision – eg surgery to centralise field of BSV (so need to know where it is and where aiming to move to)
For the UFOF you instruct the patient to let you know when they can no longer directly look at the target, but they might not understand these instructions – how can you be sure they are giving you the correct response?
Watch them subjectively and the end point is where they stop following the target
The Takagi/Goldmann are also used for visual field testing. How does testing differ from the UFOF?
Fixation is maintained in a central static position in visual field testing. However in UFOF (and field of BSV) the target is being followed. In UFOF target is moving from central to peripheral, in VF target moved from peripheral to central.
For the UFoF you set up the patient on the Takagi by aligning the cross through the peep hole with the centre of the pupil, but how do you set up a patient to plot their field of BSV?
Align so that cross is on bridge of nose, downside is that you then can’t watch subjective movement, so for some patients, clinicians will choose to adjust position so they can still see eye.
When testing the field of BSV in extreme gaze how can you check they are able to view the target with both eyes (as e.g. their nose might be blocking the image from one eye so you are no longer assessing them binocularly)?
Occlude each eye and make sure target still seen.
In primary position the patient is complaining of diplopia. They have a displaced field of BSV. How can you assess this using the Takagi? And with the arc perimeter?
Find the area where the target is single and work outwards from there, plotting where it stays single and when it goes double.
How would you describe the following field of BSV? What could be the possible diagnosis?
This Field of BSV chart isn’t labelled so assuming this is as you look at patient – ie left side of the chart represents patient’s right (importance of labelling!).
