Multifocal techniques are used in
electroretinogram and
visual evoked potential recordings to separate the responses originating from the stimulation of different locations in the
visual field (and thus different
retinal locations).
The concept is as follows: Each visual field location is stimulated with a
stimulus sequence that is
uncorrelated
In probability theory and statistics, two real-valued random variables, X, Y, are said to be uncorrelated if their covariance, \operatorname ,Y= \operatorname Y- \operatorname \operatorname /math>, is zero. If two variables are uncorrelated, there ...
to the sequences used for the other locations. All visual field locations are stimulated in parallel with their individual stimulus sequence. The retinal or cortical activity, which is a mixture of the responses from all visual field locations, is recorded with usual electroretinographic or visual evoked potential methods, respectively. Due to the independence of the stimulus sequences, the responses for each visual field location can be extracted using mathematical algorithms.
Mutifocal techniques, in particular the multifocal ERG, are used in the
diagnosis of
ophthalmological
Ophthalmology ( ) is a surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders.
An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a medic ...
diseases. The multifocal technique was developed in the early 1990s in the laboratory of Erich Sutter at the
Smith-Kettlewell Eye Research Institute
References
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Diagnostic ophthalmology