The Use of Pupillometry in Joint and Connective Tissue Diseases

Abstract

The central and peripheral nervous systems are variably affected in the rheumatic diseases. Automated standardized infrared pupillometry allows the safe, noninvasive assessment of the pupillary innervation. Pupillometry has already been used in studying the autonomic nervous system (ANS) in various rheumatic diseases. In systemic lupus erythematosus, the irideal parasympathetic branch of ANS was more affected then the sympathetic branch. In Sjögren's syndrome, signs of pupillary parasympathetic denervation have been reported. In rheumatoid arthritis, pupil parasympathetic dysfunction has been shown to correlate with ocular dryness. In systemic sclerosis (SSc), both sympathetic and parasympathetic irideal impairment have been demonstrated. Beside providing autonomic innervation, sensory nerves fibers are able to control iris diameter. Exogenous ocular instillation of substance P (SP), a sensory neuropeptide, can determine an omathropine-resistant, non-cholinergic myosis, acting on specific receptors present on the iris sphincter muscle. We first studied pupillary SP-ergic responsiveness in SSc, evaluating substance P (SP)-stimulated pupillary diameters by pupillometry. A higher basal and SP-stimulated myosis was found in lSSc versus both dSSc and controls, whereas no differences existed between dSSc and controls. From the literature, the pupillary parasympathetic nervous system seems to be more affected than the sympathetic branch of ANS in the rheumatic diseases characterized by an inflammatory status. However, we found in SSc both sympathetic and parasympathetic pupil control to be equally impaired. From our experience, we conclude that pupillary nervous control is differently affected in the two subsets of SSc, and that the SP-ergic system seems to be impaired only in lSSc.

Immediate effects of a thoracic spine thrust manipulation on the autonomic nervous system: a randomized clinical trial

“…Pupillometry has been previously used to measure the pupil and has been shown to be an easy, valid, and reliable method of assessing the nervous system without the presence of much examiner bias. [52][53][54]71,72,74,[77][78][79]92 It has been shown that the pupil dilates as a result of noxious stimulation and that the pathway through which the sympathetic systems creates dilation passes through the midbrain and the hypothalamus, which indicates a central supraspinal mechanism affecting the pupil diameter. 93 However, the diameter itself is by no means only pain specific.…”

“…49,52,54,56,69,70 Fully automated pupillometry devices have been used previously in a number of studies investigating autonomic nervous system activity. 53,56,[71][72][73][74][75][76] The human eye has difficulties detecting differences of the pupil that are smaller than 1.0 mm.…”

“…80,81 Other studies have shown that pupillometry is sensitive enough to identify autonomic differences. 53,79,82,83 The pupil responses during this study were measured with the fully automated Vorteq H system.…”

“…14 Owing to the pupils exclusive autonomic innervation, more recently an interest has emerged to measure the pupil diameter to obtain a direct impression of autonomic function. [53][54][55][56] A dilation of the pupil is a result of simultaneous increasing activity of the sympathetic system and decreasing parasympathetic activity. 45,47,49 There is a lack in the literature accounting for some of the neurophysiological effects that seem to take place following manipulation techniques.…”

Immediate Effects of the Audible Pop From a Thoracic Spine Thrust Manipulation on the Autonomic Nervous System and Pain: A Secondary Analysis of a Randomized Clinical Trial

“…34,37,43,44 Based on a negative feedback mechanism within the autonomic nervous system and its exclusive innervation, the pupil diameter can be considered as a direct "live" reflection of the functional balance between the sympathetic and parasympathetic nervous system. 37,43,[45][46][47][48] A simultaneous increasing activity of the sympathetic system and decreasing parasympathetic activity will result in a dilation of the pupil. 34,43,49,50 In addition, it has been demonstrated that sympathetic activation through the upper thoracic spine segments can cause pupil dilation.…”