Structural Characterization of Glaucoma Patients with Low Ocular Blood Flow

ABSTRACT

Purpose: There is an unclear relationship between ocular blood flow (OBF) and the structural characteristics of the optic nerve head (ONH) in glaucoma, a multifactorial disease. This study used laser speckle flowgraphy (LSFG) to identify low-OBF glaucoma patients and investigated the ONH in these patients.

Materials and Methods: In 533 eyes with glaucoma, we determined confounding factors for LSFG-measured OBF (tissue-area mean blur rate: MT) and corrected MT with a linear mixed-effects model (LMM). Structural ONH data (from fundus stereo photography), OCT data, and clinical characteristics were then compared in patients with corrected MT in the upper and lower quartiles using the LMM.

Results: Single regression showed significant correlations between MT and age, spherical equivalent (SE), central corneal thickness (CCT), and a weighted count of retinal ganglion cells (wRGC), but not axial length or systemic blood pressure. Gender also significantly influenced MT; MT was corrected for these correlated factors and also glaucoma type with the LMM. The lower-quartile MT group had a significantly larger cup area and cup-disc area ratio and lower temporal quadrant circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and macular ganglion cell complex (GCC) than the upper-quartile group.

Conclusions: Low-OBF glaucoma patients were characterized by a larger cup-disc ratio, and higher susceptibility to damage in the temporal disc and the macular area.

KEYWORDS:

• Ocular blood flow
• optical coherence tomography
• stereo photography
• quantitative topography
• glaucoma

Acknowledgments

The authors thank Mr. Tim Hilts for editing this manuscript and Ms. Junko Ouchi and Ms. Seri Fukuoka for technical assistance.

Declaration of interest

Co-authors GA, TK, and MA are employed by Topcon Corporation, a commercial company. There are no patents, products in development or marketed products to declare. The other authors have no potential conflicts of interest associated with this manuscript.

Sources of support

Topcon Corporation provided support in the form of salaries for authors GA, TK, and MA, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section. This paper was supported in part by JST grants from JSPS KAKENHI Grants-in-Aid for Scientific Research (B) (T.N. 17H04349) and for Exploratory Research (T.N. 16K15730), by the JST Center for Revitalization Promotion and KAKENHI Grant-in-Aid for young scientists (B) (K.O. 17K16957), and by the Public Trust Suda Memorial Fund for Glaucoma Research, and was a joint research project with the Topcon Corporation.

Précis:

We investigated a glaucoma subgroup with low ocular blood flow after adjusting for confounding factors; the optic nerve head in this group had a characteristic structure and higher susceptibility in the temporal area.

Additional information

Funding

This work was supported by the the Public Trust Suda Memorial Fund for Glaucoma Research; JST grants for Exploratory Research [T.N. 16K15730]; JST Center for Revitalization Promotion and KAKENHI Grant-in-Aid for young scientists (B) [K.O. 17K16957]; JST grants from JSPS KAKENHI Grants-in-Aid for Scientific Research (B) [T.N. 17H04349].