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Rao and co-workers undertook an unusual and interesting study - the influence of different strategies of instructing patients before performing standard computerized perimetry. They compared three different: an oral instruction, a video instruction and a combination of both in 90 field-naïve patients. The instructions before the first test were all very ambitious compared to what I believe constitutes the average clinical standard. Thus, the authors spent five minutes for the oral instructions with a very comprehensive list of 15 items, and similarly for the video presentation.
There were few statistically significant differences in the results among the three groups, but there was a clear tendency for better reliability, as expressed by lower FN and FP rates in patients with severe or end-stage field loss (MD worse than -12dB), who had received both verbal and video instructions. The relatively small sample size limits the conclusions, but is also a factor that might have masked other differences between the three approaches.
The main importance of this paper is that it highlights the importance of giving proper instructions to all patients who undergo computerized visual field testing for the first time. During my whole career, I have heard complaints that many patients cannot undergo standard automated perimetry. This, in my opinion, is totally wrong. Our experience from EMGT is that almost 100% of patients can do SAP, if really well instructed and supervised before and during the first one or two tests.
Our experience from EMGT is that almost 100% of patients can do SAP, if really well instructed and supervisedI would love to see the differences in results obtained in patients instructed in any of the three ambitious ways that Rao et al. used, and a normal sloppy instruction of the type that I feel that we have all seen far too often.