A novel 8-mm Schlemm's canal scaffold reduces outflow resistance in a human anterior segment perfusion model

Vikas Gulati, Shan Fan, Cassandra L. Hays, Thomas W. Samuelson, Iqbal Ike K Ahmed, Carol B Toris

Research output: Contribution to journalArticle

24 Scopus citations


Purpose. To study the effect on outflow facility and outflow resistance of a nitinol microstent implanted into Schlemm's canal. Methods. Using a constant pressure perfusion method, outflow facility and outflow resistance were measured in 26 pairs of dissected anterior segments from donated human eyes. Measurements were made at perfusion pressures of 10, 20, 30 and 40 mm Hg. The Hydrus Microstent was placed in Schlemm's canal of one eye and the contralateral eye underwent a sham procedure. Outflow facility and outflow resistance were measured again after the microstent implantation or sham procedure. Results. The Hydrus Microstent significantly increased outflow facility from 0.33 ± 0.17 μL/min/mm Hg to 0.52 ± 0.19 μL/min/mm Hg (P < 0.001). Outflow resistance was significantly reduced from 4.38 ± 3.03 mm Hg/μL/min at baseline to 2.34 ± 1.04 mm Hg/μL/min (P < 0.001) with the microstent. There was a linear correlation between outflow resistance at baseline and decrease in outflow resistance with the microstent (R2 = 0.89, P < 0.0001). Conclusions. The increase in outflow facility and decrease in resistance supports the potential use of the Hydrus Microstent as a surgical option to reduce intraocular pressure (IOP). The IOP-lowering effect may be higher in eyes with higher outflow resistance (and IOP) as compared with eyes with lower outflow resistance (and IOP).

Original languageEnglish (US)
Pages (from-to)1698-1704
Number of pages7
JournalInvestigative Ophthalmology and Visual Science
Issue number3
Publication statusPublished - Apr 2 2013


ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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