top of page

Science background

The eyes are a window into the brain.


OPTOVERA technology detects alterations in brain function!

OPTOVERA technology has been developed in collaboration with experts in neuroscience, artificial intelligence, iris recognition, and image processing.

It measures alterations of the Pupillary Light Reflex (PLR), the pupil reaction to changing light intensity.

The PLR is an involuntary reflex controlled by the Autonomic Nervous System.

A PLR alteration from a normal response (baseline), is an indication of brain function anomaly due to fatigue, sleep deprivation, alcohol, drug consumption (legal, illegal and prescription), or neurological disorder.

Pupillary Light Reflex (PLR)

The Pupillary Light Reflex (PLR) is an involuntary reflex that controls the size of the eye’s pupil in response to changing light intensity.


Pupil constriction and dilation are controlled by the Autonomic Nervous System (ANS)


The ANS regulates bodily processes like heart rate, digestion, respiratory rate, and pupillary response without conscious control.


Pupillary Analysis

Over the last 70 years, medical and scientific studies have established that an individual PLR response is an excellent, non-invasive index of central nervous system functionality.

As a result, PLR alteration analysis is a proven and accepted method to reveal neurological anomalies. In Fitness-for-Duty applications it is used to detect drug impairment, sleep deprivation and other impairing neurological conditions.

Pupillary analysis is used by doctors, in hospitals and intensive care units and involves the use of a pupillometer, an instrument that provides measures of pupillary size, symmetry, and reactivity.

Expensive medical grade designated pupillometers are used in a wide range of areas including anesthesiology, drug addiction, endocrinology, psychiatry, refractive surgery and sleep disorders. 

Pupillary analysis is used by police, it is performed in a subjective manner by using a penlight or flashlight to manually evaluate pupil reactivity and using a pupil gauge to estimate pupil size. However, this kind of manual pupillary assessment is subject to significant inaccuracies and inconsistencies.

Police pupillary analysis, impairment testing

Pupillary analysis in Fitness-for-Duty screening

​Fitness-for-Duty means that an individual is in a physical and mental state to be able to perform the essential tasks of his or her work assignment in a manner which does not threaten the safety or health of oneself, co-workers, property, or the public at large. The Pupillary Light Reflex is sensitive to a variety of impairing drugs, sleep deprivation and other impairing neurological conditions, as such, pupillary analysis can be used for impairment risk detection and Fitness-for-Duty applications.

​OPTOVERA has pioneered the use of smartphones for pupillary analysis. The company has developed the unique know-how of using available smartphone cameras, designed for consumer use, to make reliable and accurate biometric measurements.


The patented technology uses a testing device, comprising of an opaque enclosure containing a latest generation smartphone, to analyze pupillary responses at a fraction of the cost of medical grade designated pupillometers.


Each measurement is compared against the individual’s baseline to detect alterations of pupillary response. The results are specific to each person and therefore extremely accurate. The innovative approach delivers the most convenient and effective solution to measure impairment risk on-the-job, in real time, when it matters most.

The supplied testing devices include smartphones pre-configured and locked to work exclusively with SOBEREYE patented software.


PLR Research summary

The correlation between PLR alterations and impairing neurological conditions has been extensively studied, here is a summary of some of the findings and bibliographic references.

  • Pickworth [1] [2] [3], Jasinski [4], and Cone [5] have demonstrated a strong effect on pupil diameter and amplitude (both reduced) by all the major opiates including heroin, morphine, and codeine. 

  • Rowbotham [6] [7] has reported significant increases in pupil diameter for subjects given intravenous and oral cocaine. 

  • Tennant [8] has reported similar increases for amphetamines. Tennant also describes pupillary changes resulting from marijuana, benzodiazepines (Valium), alcohol, and phencyclidine (PCP). 

  • Lowenstein [9] and Yoss [10] studied changes in the shape and stability of the pupil light reflex as a person moves from alertness through fatigue to sleep. The findings show that extreme fatigue causes reduced pupil diameter and unstable pupil responses. 

  • Różanowsky et all [12] were able to demonstrate correlation and confirm the usefulness of PLR analysis in the assessment of sleep deprivation

  • Pupillary changes also occur in some neurological conditions. Profound pupillary changes are often observed as a result of brain lesions or tumors as well as impending stroke [11].


[1]     H. L. a. P. J. F. Wallace B. Pickworth, Buprenorphine- Induced Pupillary Effects In Human Volunteers, vol. 47, Life Sciences, 1990, pp. 1269-1277.

[2]     P. W. J. H. a. E. C. Wallace B. Pickworth, Opiate-Induced Pupillary Effects In Humans, vol. Methods And Findings In Experimental Pharmacology, 1989, pp. 759-763.

[3]     R. V. F. a. E. B. B. Wallace B. Pickworth, "Effects of abused drugs on pupillary size and light reflex," in Drug Abuse Handbook, CRC Press LLC, 1998.

[4]     P. J. F. A. R. E. J. Donald R. Jasinski, "Sublingual Versus Subcutaneous Buprenorphine in Opiate Abusers," Clinical Pharmacology & Therapeutics, 1989.

5]     E. J. Cone, "Testing Human Hair For Drugs Of Abuse. Individual Dose And Time Profiles Of Morphine and Codeine In Plasma, Saliva Urine and Beard Compared to Induced Effects On Pupils And Behavior," Journal Of Analytical Toxicology, no. Jan-Feb, 1990.

[6]     R. J. A. N. B. M.C. Robotham, "Trazadone-Oral Cocaine Interactions," Archives Of General Psychiatry, vol. 41, pp. 895-899, 1984.


[7]   W. H. J. M. a. R. J. M.C. Rowbotham, "Cocaine- Calcium Channel Antagonist Interactions," Psychopharmacology, no. 93, pp. 152-154, 1987.

[8]   F. Tennant, "The Rapid Eye Test To Detect Drug Abuse," Post Graduate Medicine, vol. 84, pp. 108-114, 1988.

[9]   O. L. a. I. Lowenfeld, "Types Of Central Autonomic Innervation And Fatigue," Archives Of Neurology And Psychiatry, vol. 66, pp. 581-599, 1951.

[10]   N. M. a. R. H. R. Yoss, "Pupil Size And Spontaneous Pupillary Waves Associated With Alertness, Drowsiness and Sleep," Neurology, vol. 20, pp. 545-554, 1970.

[11]   P. S. a. J. T. R. Burde, Clinical Decisions In Neuro-Ophthalmology, The C.V. Mosby Company, 1985, pp. 221-245.

[12]  K. Różanowsky, M. B. A. K., Estimation of operators' fatigue using optical methods for determination of pupil activity, International Journal of Occupational Medicine and Environmental Health, 2015, 28(2):263 – 281

bottom of page