Improvement in outflow facility by two novel microinvasive glaucoma surgery implants

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

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Purpose. To determine improvement in outflow facility (C) in human anterior segments implanted with a novel Schlemm's canal scaffold or two trabecular micro-bypasses. Methods. Human anterior segments were isolated from 12 pairs of eyes from donors with no history of ocular disease and then perfused at 50, 40, 30, 20, and 10 mm Hg pressures for 10 minutes each. Baseline C was calculated from perfusion pressures and flow rates. The scaffold was implanted into Schlemm's canal of one anterior segment, and two micro-bypasses were implanted three clock-hours apart in the contralateral anterior segment. Outflow facility and resistance were compared at various standardized perfusion pressures and between each device. Results. Compared to baseline, C increased by 0.16 ± 0.12 μL/min/mm Hg (74%) with the scaffold, and 0.08 ± 0.12 μL/min/mm Hg (34%) with two micro-bypasses. The scaffold increased C at perfusion pressures of 50, 40, 30, and 20 mm Hg (P < 0.005). Two micro-bypasses increased C at a perfusion pressure of 40 mm Hg (P < 0.05). Conclusions. Both implants effectively increased C in human eyes ex vivo. The scaffold increased C by a greater percentage (73% vs. 34%) and at a greater range of perfusion pressures (20 to 50 mm Hg vs. 40 mm Hg) than the two micro-bypasses, suggesting that the 8-mm dilation of Schlemm's canal by the scaffold may have additional benefits in lowering the outflow resistance. The Hydrus Microstent scaffold may be an effective therapy for increasing outflow facility and thus reducing the IOP in patients with glaucoma.

Original languageEnglish (US)
Pages (from-to)1893-1900
Number of pages8
JournalInvestigative Ophthalmology and Visual Science
Volume55
Issue number3
DOIs
StatePublished - Jan 1 2014

Fingerprint

Glaucoma
Pressure
Perfusion
Eye Diseases
Dilatation
Tissue Donors
Equipment and Supplies

Keywords

  • Drainage device
  • Glaucoma anterior segment
  • Outflow facility
  • Schlemm's canal

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

Improvement in outflow facility by two novel microinvasive glaucoma surgery implants. / Hays, Cassandra L.; Gulati, Vikas; Fan, Shan; Samuelson, Thomas W.; Ahmed, Iqbal Ike K; Toris, Carol B.

In: Investigative Ophthalmology and Visual Science, Vol. 55, No. 3, 01.01.2014, p. 1893-1900.

Research output: Contribution to journalArticle

@article{582fbc88ae024072a5c671f75beaabda,
title = "Improvement in outflow facility by two novel microinvasive glaucoma surgery implants",
abstract = "Purpose. To determine improvement in outflow facility (C) in human anterior segments implanted with a novel Schlemm's canal scaffold or two trabecular micro-bypasses. Methods. Human anterior segments were isolated from 12 pairs of eyes from donors with no history of ocular disease and then perfused at 50, 40, 30, 20, and 10 mm Hg pressures for 10 minutes each. Baseline C was calculated from perfusion pressures and flow rates. The scaffold was implanted into Schlemm's canal of one anterior segment, and two micro-bypasses were implanted three clock-hours apart in the contralateral anterior segment. Outflow facility and resistance were compared at various standardized perfusion pressures and between each device. Results. Compared to baseline, C increased by 0.16 ± 0.12 μL/min/mm Hg (74{\%}) with the scaffold, and 0.08 ± 0.12 μL/min/mm Hg (34{\%}) with two micro-bypasses. The scaffold increased C at perfusion pressures of 50, 40, 30, and 20 mm Hg (P < 0.005). Two micro-bypasses increased C at a perfusion pressure of 40 mm Hg (P < 0.05). Conclusions. Both implants effectively increased C in human eyes ex vivo. The scaffold increased C by a greater percentage (73{\%} vs. 34{\%}) and at a greater range of perfusion pressures (20 to 50 mm Hg vs. 40 mm Hg) than the two micro-bypasses, suggesting that the 8-mm dilation of Schlemm's canal by the scaffold may have additional benefits in lowering the outflow resistance. The Hydrus Microstent scaffold may be an effective therapy for increasing outflow facility and thus reducing the IOP in patients with glaucoma.",
keywords = "Drainage device, Glaucoma anterior segment, Outflow facility, Schlemm's canal",
author = "Hays, {Cassandra L.} and Vikas Gulati and Shan Fan and Samuelson, {Thomas W.} and Ahmed, {Iqbal Ike K} and Toris, {Carol B}",
year = "2014",
month = "1",
day = "1",
doi = "10.1167/iovs.13-13353",
language = "English (US)",
volume = "55",
pages = "1893--1900",
journal = "Investigative Ophthalmology and Visual Science",
issn = "0146-0404",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "3",

}

TY - JOUR

T1 - Improvement in outflow facility by two novel microinvasive glaucoma surgery implants

AU - Hays, Cassandra L.

AU - Gulati, Vikas

AU - Fan, Shan

AU - Samuelson, Thomas W.

AU - Ahmed, Iqbal Ike K

AU - Toris, Carol B

PY - 2014/1/1

Y1 - 2014/1/1

N2 - Purpose. To determine improvement in outflow facility (C) in human anterior segments implanted with a novel Schlemm's canal scaffold or two trabecular micro-bypasses. Methods. Human anterior segments were isolated from 12 pairs of eyes from donors with no history of ocular disease and then perfused at 50, 40, 30, 20, and 10 mm Hg pressures for 10 minutes each. Baseline C was calculated from perfusion pressures and flow rates. The scaffold was implanted into Schlemm's canal of one anterior segment, and two micro-bypasses were implanted three clock-hours apart in the contralateral anterior segment. Outflow facility and resistance were compared at various standardized perfusion pressures and between each device. Results. Compared to baseline, C increased by 0.16 ± 0.12 μL/min/mm Hg (74%) with the scaffold, and 0.08 ± 0.12 μL/min/mm Hg (34%) with two micro-bypasses. The scaffold increased C at perfusion pressures of 50, 40, 30, and 20 mm Hg (P < 0.005). Two micro-bypasses increased C at a perfusion pressure of 40 mm Hg (P < 0.05). Conclusions. Both implants effectively increased C in human eyes ex vivo. The scaffold increased C by a greater percentage (73% vs. 34%) and at a greater range of perfusion pressures (20 to 50 mm Hg vs. 40 mm Hg) than the two micro-bypasses, suggesting that the 8-mm dilation of Schlemm's canal by the scaffold may have additional benefits in lowering the outflow resistance. The Hydrus Microstent scaffold may be an effective therapy for increasing outflow facility and thus reducing the IOP in patients with glaucoma.

AB - Purpose. To determine improvement in outflow facility (C) in human anterior segments implanted with a novel Schlemm's canal scaffold or two trabecular micro-bypasses. Methods. Human anterior segments were isolated from 12 pairs of eyes from donors with no history of ocular disease and then perfused at 50, 40, 30, 20, and 10 mm Hg pressures for 10 minutes each. Baseline C was calculated from perfusion pressures and flow rates. The scaffold was implanted into Schlemm's canal of one anterior segment, and two micro-bypasses were implanted three clock-hours apart in the contralateral anterior segment. Outflow facility and resistance were compared at various standardized perfusion pressures and between each device. Results. Compared to baseline, C increased by 0.16 ± 0.12 μL/min/mm Hg (74%) with the scaffold, and 0.08 ± 0.12 μL/min/mm Hg (34%) with two micro-bypasses. The scaffold increased C at perfusion pressures of 50, 40, 30, and 20 mm Hg (P < 0.005). Two micro-bypasses increased C at a perfusion pressure of 40 mm Hg (P < 0.05). Conclusions. Both implants effectively increased C in human eyes ex vivo. The scaffold increased C by a greater percentage (73% vs. 34%) and at a greater range of perfusion pressures (20 to 50 mm Hg vs. 40 mm Hg) than the two micro-bypasses, suggesting that the 8-mm dilation of Schlemm's canal by the scaffold may have additional benefits in lowering the outflow resistance. The Hydrus Microstent scaffold may be an effective therapy for increasing outflow facility and thus reducing the IOP in patients with glaucoma.

KW - Drainage device

KW - Glaucoma anterior segment

KW - Outflow facility

KW - Schlemm's canal

UR - http://www.scopus.com/inward/record.url?scp=84897130319&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84897130319&partnerID=8YFLogxK

U2 - 10.1167/iovs.13-13353

DO - 10.1167/iovs.13-13353

M3 - Article

C2 - 24550367

AN - SCOPUS:84897130319

VL - 55

SP - 1893

EP - 1900

JO - Investigative Ophthalmology and Visual Science

JF - Investigative Ophthalmology and Visual Science

SN - 0146-0404

IS - 3

ER -