Optic Nerve Head Blood Flow, as Measured by Laser Speckle Flowgraphy, Is Significantly Reduced in Preperimetric Glaucoma

ABSTRACT

Purpose: To compare optic nerve head (ONH) blood flow in healthy eyes, eyes with preperimetric glaucoma (PPG), and eyes with mild normal-tension glaucoma (NTG) using laser speckle flowgraphy (LSFG).Methods: In 172 eyes (normal: 44 eyes; PPG: 62 eyes; mild NTG: 66 eyes), LSFG was used to measure mean blur rate in the ONH tissue area (MBR_T), an index of capillary blood flow. Multiple regression analysis was performed to determine factors affecting circumpapillary retinal nerve fiber layer thickness (cpRNFLT), mean deviation (MD) and pattern standard deviation (PSD) of the visual field.Results: Despite similar characteristics in age, refractive error and systemic variables among the study groups, MBR_T in the normal eyes differed significantly from both the PPG and mild NTG eyes (P = 0.001, P < 0.001, respectively). Multiple regression analysis revealed that MBR_T was an independent factor affecting cpRNFLT, MD and PSD (P < 0.001, P = 0.001, P = 0.003, respectively).Conclusion: ONH blood flow was detectibly reduced in eyes with PPG, in close association with structural and visual field damage. This suggests that measuring ONH tissue-area blood flow with LSFG may be a useful way of monitoring glaucoma severity, even in the early stages of glaucoma.

KEYWORDS:

• Laser speckle flowgraphy
• optic nerve head
• ocular blood flow
• preperimetric glaucoma
• glaucoma

Acknowledgments

The authors thank Kunimatsu-Sanuki Shiho and Morin Ryu for valuable comments and Junko Ouchi, Shiori Suzuki, Shizuka Kato, Kenji Tanaka, Ayako Kawakami, Hiromi Ooki, and Yuta Otowa for technical support, and Mr. Tim Hilts for reviewing the manuscript.

Declaration of interest

There were no conflicts of interest in this study.

Funding

Funding was received from Santen Pharmaceutical Co. Ltd.This potential conflict of interest has been reviewed by the Institutional Review Board of the Tohoku Graduate School of Medicine.This study was supported by Santen Pharmaceutical Co. Ltd., by JSPS KAKENHI Grants-in-Aid for Scientific Research (B) (T.N. 26293372) and for Exploratory Research (T.N. 26670751) and by the JST Center for Revitalization Promotion.

Additional information

Funding

Funding was received from Santen Pharmaceutical Co. Ltd.This potential conflict of interest has been reviewed by the Institutional Review Board of the Tohoku Graduate School of Medicine.This study was supported by Santen Pharmaceutical Co. Ltd., by JSPS KAKENHI Grants-in-Aid for Scientific Research (B) (T.N. 26293372) and for Exploratory Research (T.N. 26670751) and by the JST Center for Revitalization Promotion.