Ultrasound for Pupillary Assessment - A Systematic Review

Background

The conventional clinical assessment of pupils & pupillometers has shown very poor interrater reliability. As a promising alternative, bedside ultrasound has emerged for pupillary assessment.

Objectives

Thus, we conducted a systematic review to assess ultrasound's utility and comparative effectiveness in pupillary assessment.

Methods

This systematic review involved searching three major databases—PubMed, Embase, and Scopus—from inception to April 2024, using predefined search terms. Inclusion criteria comprised adult patients over 18 years undergoing ultrasound for pupillary assessment, with comparison against standard methods such as pupillometry or clinical examination. Screening and data extraction were independently conducted by two investigators (GR, SM), with data appraisal utilizing the QUADAS-2 Risk of Bias assessment tool (CRD42024540402).

Results

Among 556 identified studies, seven met inclusion criteria, encompassing 865 patients and 1141 ultrasonographic pupillary assessments. Six of these studies reported a favourable correlation or association between ultrasound and pupillometer or clinical examination. Significant findings included a substantial correlation between ultrasound and infrared video pupillometry by Farina et al. (R = 0.831, p < 0.01), by Fu et al. (Bland-Altman agreement −0.069) & Modi et al. (Interclass Correlation Coefficient = 0.93). Diagnostic accuracy for identifying Relative Afferent Pupillary Defect (RAPD) had high sensitivity and specificity reported by Ramamoorthy et al. and Schmidt et al.

Conclusion

Our systematic review demonstrates a significant correlation/association between ultrasound and pupillometer or clinical examination for pupillary assessment. However, current evidence remains limited, and further high-quality research is needed before recommending routine use or claiming superiority over pupillometry or standard clinical assessments.