Ultrasound Examination of the Pupil – A New Tool for the Neuro-Ophthalmological Assessment

Abstract

Background Pupil examination represents a diagnostic and prognostic test in the management of several neurological diseases. Infrared video pupillometry (IVP) is the gold standard, since it is not routinely available, a noninvasive bedside ultrasound assessment has been proposed as an alternative. The aim of this study was to assess the feasibility and reproducibility of ultrasound pupillometry (UP) in comparison with IVP. Materials and Methods 81 subjects (43 men and 38 women, mean age: 52 ± 20 years and 49 ± 19 years, respectively) with no history of neurophthalmologic disease were enrolled. UP was performed with a 12-MHz linear probe according to current guidelines for orbital insonation. Light and painful stimuli were applied to test pupillary light reflex (PLR) and ciliospinal reflex (CR). In 30 of these subjects IVP examination was performed additionally to obtain intra-observer and inter-observer agreement. Results Increasing age was associated with a decreased pupillary diameter (PD) at rest, after PLR and CR (R –0.728, p < 0.01, R –0.643, p < 0.01, R 0.674, p < 0.001 respectively), while no association was noticed with time to constriction/dilation. UP measurements were reproducible (rate of inter- and intra-observer agreement: R 0.979, p < 0.01, R 0.946, p < 0.01 respectively) and concordant with IVP (PLR R 0.831, p < 0.01; CR R 0.879, p < 0.01). Conclusion According to our study, ultrasound pupillometry is a feasible and reliable technique for bedside pupillary function assessment, and is a good alternative to infrared video pupillometry. Moreover, it represents the only way for functional pupillary assessment in patients with periorbital hematoma.

Utility of M-mode ultrasound for pupillary assessment in patients with traumatic brain injury

“…Although ultrasound pupillary assessment requires a certain degree of experience, this method provides the possibility to monitor pupillary parameters, especially pupillary size, symmetry, changes in contraction under light stimulation, and dilation/contraction speed. Previously, studies by Schmidt et al and Farina et al con rmed the feasibility of monitoring pupillary size and pupillary constriction velocity by ultrasound 15,21 ; however, both used B-mode ultrasound. In this study, we evaluated the utility of M-mode ultrasound in monitoring PD and introduced the concept of PDVR, using objective data to re ect PLR sensitivity.…”

Neurologic Complications of Critical Medical Illness

“…This makes them very sensitive markers of uncal herniation. In patients with eyelid swelling or orbital trauma impairing access to the pupil, ultrasonography can be used to assess the consensual pupillary reflex 8 …”

Diagnostic Ultrasonography in Neurology

“…During the same examination, the clinician can also assess the presence of papilledema, that is, the prominence of the papilla ( figure 12-19 ), with the normal value of less than 0.5 mm. In several neurologic conditions, including in neurocritical settings, pupillometry can be done with ultrasonography with very good accuracy 56 …”

“…In several neurologic conditions, including in neurocritical settings, pupillometry can be done with ultrasonography with very good accuracy. 56 Regarding vascular disease in acute vision loss, in addition to assessing for a carotid stenosis, blood flow velocity can be evaluated in the central retinal artery running within the optic nerve. Sometimes it is possible to identify a calcified embolus (suggestive of arterial plaque embolism) lodging in the central retinal artery just behind the papilla.…”