Paired assessments will be made on patients who are consented; and on healthy controls who have verbally assented to participate. We plan to enroll 20 patients and 50 healthy controls. Assessments will be made at the convenience of the patient and healthy controls. Each assessment will include bilateral PLR reading within a 5 minute interval. The first assessment will be completed with the NPi-200 and the second assessment will use the NPi-300. The data will be entered into a CRF.~If there is a significant difference between readings from the NPi-200 and the NPi-300, we will repeat the bilateral assessment in the following hour and the regularly scheduled time.
The purpose of this study is to explore the inter-device reliability between the NPi-200 and NPi-300.