Accuracy of pupil assessment for the detection of glaucoma: a systematic review and meta-analysis

Abstract

Objective: To assess the accuracy of using pupillary light reflex (PLR) in detecting glaucoma.

Clinical relevance: Glaucoma is a specific disease of the optic nerve and is often more severe in 1 eye. When large enough, this asymmetry in disease severity can cause a relative afferent pupillary defect (RAPD). Better detection of RAPDs may be one way to identify persons with glaucoma.

Methods: We searched Medline and Embase through June 2012 and searched bibliographies for relevant studies for additional references. Two authors independently reviewed all articles and selected studies that assessed PLRs in patients with glaucoma. We analyzed data using mixed-effect bivariate summary receiver operating characteristic meta-analysis models.

Results: A total of 30 studies were included in this review. An RAPD was observed in 9% to 82% of patients with glaucoma. Eleven studies with a total of 7271 participants were included in the analysis, and the pooled estimate corresponded to a sensitivity of 0.63 (95% confidence interval [CI], 0.43-0.80) and a specificity of 0.93 (95% CI, 0.85-0.97). After excluding 2 studies that used the swinging flashlight test, the sensitivity increased to 0.74 (95% CI, 0.59-0.85) with a specificity of 0.85 (95% CI, 0.77-0.90). Study designs and different pupil measurement techniques explained part of the heterogeneity between studies.

Conclusions: Patients with glaucoma frequently have an abnormal PLR and comparing the responses between the 2 eyes can in part distinguish between those with glaucoma and those without the disease. Newer instruments and analytic approaches to assess pupil function may improve the performance of pupil screening.

Figure 1

Flow of study selection.

Figure 2

Methodological quality summary for each included study.

Figure 3

Forest plot of included studies. The estimated sensitivity and specificity of the study (square) and its 95% CI (horizontal line) are shown. The diamonds represent the summary estimates of all 11 studies (COMBINED N=11, A+C+D) or the sensitivity analysis of 9 studies, excluding 2 that used SFT (COMBINED N=9, C+D). Swinging flashlight test (A), pupillography (C), and pupil perimetry (D). Numbers in parentheses indicate the corresponding reference.

Figure 4

A, The summary receiver operating curve (SROC) plot for detection of glaucoma. The solid line is the summary receiver operating characteristic curve along with its 95% prediction region, which gives an indication of between study heterogeneity. The solid square represents the summary sensitivity and specificity points along its 95% confidence intervals. Swinging flashlight test (SFT) (A), pupillography (C), and pupil perimetry (D). Numbers in brackets indicate the corresponding reference. B, The summary receiver operating curve plot of the sensitivity analysis, excluding 2 studies that used the SFT in pupil assessment. C, Pupillography. D, Pupil perimetry. Numbers in brackets indicate the corresponding reference.