regarding the autonomic nervous system could manifest as a defect of pupillary response.(Bremner,
2006) Pupillometry is gaining recognition in research of migraine (Connell & Baxendale, n.d.),
psychiatry (Graur & Siegle, 2013) and autonomic disorder (Bremner, 2009). Methods to measure
pupillary response varies from using pharmacology-induced pupillary test using tropicamide (Turana
et al., 2014) to using pupillometer (Bremner, 2009). Since pupillometer only needs infra-red light and
camera to function (Martínez-Ricarte et al., 2013), the method can be simply replicated to ensure wide
coverage. Trusted ophthalmology research lab has begun to use their own version of novel
pupillometer.(Bremner, 2009) However, the debate about the efficacy, validity and reliability of pupil
movement as a biomarker of autonomic disorder is not resolved. The purpose of this study is to
evaluate the use of pupillometer and its probability as a device to diagnose patients with autonomic
disorder.
Research Methodology
In this literature review, we used the scholarly search engine Proquest, Springerlink and Google
Scholar. The keywords used are “pupillary response”, “pupillometry” and “autonomic nervous
system” or “autonomic disorder”. Using Proquest, we found 82 scholarly journals published from
1984-2014. From those numbers, 63 were published between the year 2005 and 2015. From
Springerlink, 3 publications meets the purpose of the study. In the end, 5 studies suit the purpose of
the research and is included.
Results
The basic principle of pupillometry is to measure the dynamic diameter of the pupil when given
stimuli. (Nowak, 2014) Pupillometer mainly consist of a single camera with a frame grabber that is
used to record the changing of diameter, optical path and infrared illumination (Figure 1).
Measurements can be done monocular and binocular, although binocular measuring of the left and
right eye using a single camera is recommended. Normal pupillograph are shown in Figure 2.
Variability in pupil response helps locate the lesion of the disorder.(Muppidi et al., 2013) Autonomic
disorder affecting the brain stem or peripheral autonomic ganglia could be associated with pupillary
dysfunction. Conditions such as diabetes with or without cardiac autonomic neuropathy (CAD) results
significant pupillary response difference within healthy patients and healthy control.(Ferrari et al.,
2010)The ratio of pupil in darkness differs significantly between the healthy control, diabetic patients
without CAD and diabetic patients with CAD. Healthy controls have shorter latency period from flash
exposure to the start of constriction and greater iris-pupil ratio in the frame of largest constriction. The
duration of constriction is not significantly different.
Autoimmune autonomic gangliopathy (AAG) patients are also reported to show signs of
parasympathetic deficit in the pupillary response test.(Muppidi et al., 2013)
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