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. 2019 May 13;7:e6929. doi: 10.7717/peerj.6929

Figure 1. Pupillary dilation during mental arrithmetic assessed by automated pupillometry.

Figure 1

We used the PLR®-3000 pupillometer (NeurOptics, Laguna Hills, CA, USA), an automated handheld device (A and B), to track pupillary size, while asking patients and healthy volunteers (one shown here; permission obtained) to perform mental arithmetic. The examiner holds the pupillometer in one hand and covers the other eye with the other hand (A). The set-up is identical for healthy volunteers and patients, except that patients may be better examined in the supine position.