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Kim E. Kutzko, Caridad F. Brito, Michael Wall; Effect of Instructions on Conventional Automated Perimetry. Invest. Ophthalmol. Vis. Sci. 2000;41(7):2006-2013.
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purpose. To investigate the effect of perimetrists’ instructions on automated
methods. Eighteen volunteers in two age groups participated in a series of three
test sessions. Each session consisted of a Humphrey Field Analyzer 30-2
test, a questionnaire, and a customized test program using a Humphrey
perimeter to construct frequency of seeing (FOS) curves from which
thresholds were calculated, and a descriptive measure of response
criterion was derived. The FOS curves were obtained at a central and a
peripheral test location within the same test session. The three test
sessions differed only by the instructions given. The instructions were
adapted from those listed in the manufacturer’s instruction manual and
were designed to influence participants to respond to the stimuli in a
conservative, liberal, or neutral manner.
results. For the 30-2 threshold test, a significant difference in mean deviation
was found among the three instruction types (P = 0.001)
and between the two age groups (P = 0.001). Although
differences were small in the younger subjects (2.04 dB), the means for
the responses from liberal to conservative differed by 6.57 dB in the
older subjects. Thresholds obtained in a peripheral location by the
customized threshold test were found to differ significantly between
the age groups (younger group mean, 31.0 dB; older group mean, 27.2 dB)
and among the instruction types (liberal mean, 30.9 dB; conservative
mean, 28.1 dB; and neutral mean, 30.3 dB; P < 0.001).
The descriptive measurement of response criterion suggests that a
difference in criteria occurred as a result of the instructions in both
peripheral and central locations for both age groups (P = 0.0001). In addition, according to self-reports, liberal instructions
caused participants to be more likely to respond, whereas the
conservative instructions caused them to be more reluctant to respond.
conclusions. Perimetrists’ instructions can significantly affect obtained automated
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