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There has to be a better way: evolution of internal filtration glaucoma surgeries
  1. Nils A Loewen1,
  2. Joel S Schuman1,2
  1. 1Department of Ophthalmology, UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
  2. 2Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
  1. Correspondence to Professor Joel S Schuman, Department of Ophthalmology, UPMC Eye Center, University of Pittsburgh School of Medicine, 203 Lothrop Street, Eye and Ear Institute, Suite 816, Pittsburgh, PA 15213, USA; SchumanJS{at}

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Accelerating progress in biomedical engineering1 and the ability to live image and understand delicate outflow structures2 have produced an abundance of new surgical options in the last few years for an ancient disease that stubbornly defies the best hands and minds. Glaucoma, first described by Hippocrates 400 BC as vision loss in the elderly that is different from cataract,3 is now a leading cause of irreversible blindness with increasing prevalence in an aging population.4 Despite the many new arrivals, the concepts behind recent names like Trabectome,5 iStent,6 Hydrus,7 Xen,8 Solx,9 Cypass,10 Canaloplasty,11 ECP12 are not entirely new: open angle glaucoma has been surgically treated for 150–100 years by either increasing external filtration,13 internal filtration (angle surgery;14 suprachoroidal drainage15) or ciliodestruction.16

Development of new devices and technologies was spurred by the realisation that the standard surgeries performed today for glaucoma—trabeculectomy and epibulbar glaucoma drainage device surgery—have unacceptably high failure and complication rates even when performed as primary surgeries.17 While not as rudimentary and unsuccessful as at the time of their inception in the form of guarded external filtration by Sugar in 1962,18 or the gold wire shunt by De Wecker in 1876,19 both present iterations seem almost as primitive given that urgent postoperative interventions have to be performed in astonishing 74% of trabeculectomies and 27% of tube shunts.20 Serious, vision-threatening early postoperative complications occur in 39% of trabeculectomy and 22% of tube shunt patients, while additional serious complications during 5-year follow-up occur in 38% …

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  • Contributors NAL and JSS contributed to this manuscript in concept, design, writing and review.

  • Funding Supported in part by National Institutes of Health contract P30-EY08098 (Bethesda, Maryland, USA), The Eye and Ear Foundation (Pittsburgh, Pennsylvania, USA), and an unrestricted grant from Research to Prevent Blindness (New York, New York, USA).

  • Disclaimer NAL is a trabectome trainer (Neomedix Corp., Tustin, California, USA) JSS receives royalties for intellectual property licensed by Massachusetts Eye and Ear Infirmary and Massachusetts Institute of Technology to Carl Zeiss Meditec, Inc.

  • Competing interests None.

  • Provenance and peer review Commissioned; internally peer reviewed.

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