Diagnostic performance of laser speckle flowgraphy in glaucoma: a systematic review and meta-analysis

Purpose To evaluate the diagnostic value of laser speckle flowgraphy (LSFG) in glaucoma by investigating the mean blur rate (MBR) in the optic nerve head. Methods Systematic literature search was performed in the CENTRAL, Web of Science, PubMed, and EMBASE databases to obtain relevant studies published until December 2020 without restrictions. The Newcastle-Ottawa Scale (NOS) was used for study quality assessment. The outcome measures included the MBRs of the entire (MA), vascular (MV), and tissue (MT) areas. Subgroup analyses were performed according to glaucoma type. All data were analyzed using RevMan and Comprehensive Meta-Analysis 3.3 software. Results Fifteen studies, including 692 glaucomatous and 386 healthy eyes, were included. Of these, 11 studies reported the MA, MV, and MT, three studies only reported MT, and one study only reported MV. All were classified as case-control studies and had good NOS scores. The meta-analysis showed that the MA and MT were significantly reduced in glaucomatous eyes (mean difference [MD] - 5.59, 95% confidence interval [CI] - 6.19 to - 4.99, p = 0.1; MD - 2.2, 95% CI - 2.49 to - 1.91, p = 0.07, respectively) with moderate heterogeneity (p = 0.1, I-2 = 38%; p = 0.07, I-2 = 39%, respectively). There was also a significant difference in the MV between glaucomatous and healthy eyes (MD - 5.92, 95% CI - 7.77 to - 4.07) with significant heterogeneity (p = 0.0003, I-2 = 69%). The subgroup analyses revealed significant differences in the MBR among different glaucoma types. Conclusions Glaucoma is closely related to ocular blood flow changes. This meta-analysis suggests that LSFG is a feasible diagnostic tool for glaucoma. However, further longitudinal prospective studies are needed.

Automated summary

By analyzing 15 studies, it was found that LSFG has the potential feasibility for diagnosing glaucoma, by showing the mean blur rate (MBR) in the optic nerve head and demonstrating significant differences in MBR among different glaucoma types.