Inter-device reliability of the NPi-200 and NPi-300 pupillometers

Sonja Stutzman, Phebe Iype, Jade Marshall, Kinley Speir, Nathan Schneider, Conny Tran, Shannon Laird, Venkatesh Aiyagari, Daiwai Olson

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The pupillary evaluation is an essential part of the neurological examination. Research suggests that the traditional examination of the pupil with a handheld flashlight has limited interrater reliability. Automated pupillometers were developed to provide an objective scoring of various pupillary parameters. The NPi-200 pupillometer is used for quantitative pupillary examinations, the NPi-300 was launched in July 2021 with enhanced features. The purpose of this study is to compare results from the NPi-200 to the NPi-300 to ensure that data are translatable across both platforms. This study examines the inter-device reliability of the NPi-200 compared to the NPi-300 in two cohorts: 20 patients at risk for cerebral edema and 50 healthy controls. Paired assessments of the devices were made from all participants. Each assessment included bilateral PLR readings within a 5-minute interval. Data showed high agreement between the two devices for the Neurological Pupil Index (NPi) reading (k = 0.94; CI: 0.91–0.99) and for pupil diameter assessment (k = 0.91; CI: 0.87–0.96). There is a very high level of agreement between the NPi-200 and NPi-300 among healthy controls and critically ill patients. Clinicians and researchers can interpret the results from either device equally.

Original languageEnglish (US)
Pages (from-to)180-183
Number of pages4
JournalJournal of Clinical Neuroscience
StatePublished - Jun 2022


  • Cerebral edema
  • Clinical research
  • Critical care
  • Neurocritical care
  • Neurological examination
  • Nursing
  • Pupil

ASJC Scopus subject areas

  • Surgery
  • Neurology
  • Clinical Neurology
  • Physiology (medical)


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