The impact of intraocular pressure elevation on optic nerve head and choroidal blood flow

Naoki Kiyota, Yukihiro Shiga, Kohei Ichinohasama, Masayuki Yasuda, Naoko Aizawa, Kazuko Omodaka, Naoto Honda, Hiroshi Kunikata, Toru Nakazawa

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

PURPOSE. To use laser speckle flowgraphy (LSFG) to assess blood flow (BF) in the optic nerve head (ONH) tissue and choroid during elevated intraocular pressure (IOP). METHODS. This prospective study included 20 eyes of 20 healthy volunteers. The testing protocol had a baseline phase, two elevated IOP phases (+10 and +20 mm Hg), and a recovery phase. IOP was elevated by pushing against the eyelid with a novel tubular device attached to the LSFG apparatus. Measurement parameters in each phase included: LSFGderived mean blur rate (MBR) and flow acceleration index (FAI); systemic parameters, and IOP. The % change against baseline was calculated for each phase. The protocol was repeated five times to calculate the coefficient of variation (CV) for % change MBR and to determine the effect of mydriasis on % change MBR. We compared % change MBR and FAI and evaluated the relationship between % change ocular perfusion pressure (OPP) and MBR in the choroid and ONH tissue. RESULTS. The % change MBR was highly reproducible (CV: 6.1–8.7%) and not affected by mydriasis (P = 0.57–0.96). The % change MBR and FAI were higher in the ONH tissue than choroid during IOP elevation (P = 0.04). The % change OPP and MBR showed positive linear correlations and two-segmental linear correlations in the choroid and ONH tissue, respectively (P < 0.01). CONCLUSION. Hemodynamics during IOP elevation differ in the choroid and ONH tissue. LSFG enables highly reproducible assessment of the dynamic autoregulation of ocular BF in the ONH tissue.

Original languageEnglish
Pages (from-to)3488-3496
Number of pages9
JournalInvestigative Ophthalmology and Visual Science
Volume59
Issue number8
DOIs
Publication statusPublished - 2018 Jul

Keywords

  • Autoregulation
  • Laser speckle flowgraphy
  • Ocular blood flow

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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