Development of a microstent system for minimally invasive glaucoma surgery

AbstractGlaucoma is the leading cause of irreversible blindness worldwide. An increased intraocular pressure (IOP) is known as major risk factor. Currently, drainage devices that are implanted by means of minimally invasive glaucoma surgery (MIGS) represent a promising approach for IOP low-ering. Commercially available devices for MIGS suffer from unregulated drainage involving ocular hypotony. Further-more, long term drainage capability of current devices is limited by fibrotic encapsulation processes. Therefore, our group focusses on the development of a valved drug-eluting microstent for MIGS. Within the current work, we developed two alternative injector devices for minimally invasive mi-crostent implantation. Both injector devices were based on a cannula in which the microstent is loaded and a mandrel inside the cannula. Injector device A is designed to push the microstent out of the cannula and injector device B is de-signed to withdraw the cannula above the microstent. Manu-facturing of injector devices was conducted using rapid prototyping. Simplified polymeric microstents were manu-factured from polycarbonate based silicone elastomer. Simulated use was performed in a silicone eye model. The presented injector devices were suitable for minimally in-vasive ab interno microstent implantation into suprachoroidal space. Ongoing miniaturization of the microstent system will allow the use of a 22 G cannula in future ex vivo experiments.

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Canaloplasty ab interno (AbiC) – 2-Year-Results of a Novel Minimally Invasive Glaucoma Surgery (MIGS) Technique

Klinische Monatsblätter für Augenheilkunde ◽

10.1055/a-1250-8431 ◽

2020 ◽

Author(s):

Sara Kazerounian ◽

Michael Zimbelmann ◽

Martin Lörtscher ◽

Sufian Hommayda ◽

Irene Tsirkinidou ◽

...

Keyword(s):

Minimally Invasive ◽

Open Angle Glaucoma ◽

Glaucoma Surgery ◽

Eye Drops ◽

Medication Usage ◽

Minimally Invasive Glaucoma Surgery ◽

The Mean ◽

Ab Interno

Abstract Purpose The aim of this study is to evaluate the long-term efficacy of a novel minimally invasive glaucoma surgery technique (MIGS), Ab interno Canaloplasty (AbiC). Material and Methods For this retrospective cohort study, we analysed the data of 25 eyes of 23 patients with open angle glaucoma who underwent an AbiC (6 eyes) or in case of an additional cataract, a combined cataract-AbiC procedure (“phacocanaloplasty ab interno”, 19 eyes), respectively. Postoperatively, we investigated the intraocular pressure (IOP) and the number of still required IOP-lowering medication, as well as surgery-related complications. Results Overall, the mean baseline IOP of 20.24 mmHg ± 5.92 (n = 25) was reduced to 10.64 mmHg ± 2.77 (n = 25, p < 0.001), 12.55 mmHg ± 3.33 (n = 22, p < 0.001) and 13.67 mmHg ± 2.15 (n = 21, p < 0.001) at 1 day, 1 year and 2 year follow-up visit, respectively. Compared to baseline, this implies a reduction in IOP of 47.4, 37.9 and 32.5%. An average glaucoma medication usage of 1.92 ± 1.04 was registered at baseline visit and was reduced to 0,05 ± 0,23 after 2 years of follow-up. 80% of patients were off medication. In 5 eyes (20%) further antiglaucomatous eye drops or surgical treatment were administered. The only surgical complications were hyphema in 5 eyes (20%) and a localized peripheral detachment of the Descemetʼs membrane in one eye (4%) with no late sequelae. Conclusion AbiC performed independently or combined with cataract surgery seems to be a safe and effective MIGS-technique with good long-term regulation of IOP and low risk profile.

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Microhook ab interno trabeculotomy, a novel minimally invasive glaucoma surgery

Clinical Ophthalmology ◽

10.2147/opth.s152406 ◽

2017 ◽

Vol Volume 12 ◽

pp. 43-48 ◽

Cited By ~ 7

Author(s):

Masaki Tanito

Keyword(s):

Minimally Invasive ◽

Glaucoma Surgery ◽

Minimally Invasive Glaucoma Surgery ◽

Ab Interno

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Suprachoroidal MIGS Devices

Minimally Invasive Glaucoma Surgery ◽

10.1007/978-981-15-5632-6_8 ◽

2020 ◽

pp. 105-119

Author(s):

Julian Garcia-Feijoo ◽

Jose Maria Martinez-de-la-Casa ◽

Lucia Perucho

Keyword(s):

Glaucoma Surgery ◽

Cell Loss ◽

Term Efficacy ◽

Suprachoroidal Space ◽

Early Results ◽

Outflow Pathway ◽

Implanted Devices ◽

Ab Interno

Abstract The suprachoroidal outflow pathway has the potential to reduce intraocular pressure (IOP) significantly but has been associated with sight-threatening complications including severe and prolonged hypotony. Historically, suprachoroidal devices have been implanted ab externo requiring a conjunctival peritomy and scleral flap dissection. Additionally, the long-term efficacy of previous attempts to harness this space has been disappointing due to occlusion of implanted devices by fibrosis in the suprachoroidal space. More recently, there have been a number of suprachoroidal devices that are injected ab interno., including the CyPass Micro-Stent (Alcon Laboratories Inc., Fortworth, Texas, USA), the iStent Supra (Glaukos Corporation, San Clemente, CA, USA) and the MINIject (iSTAR Medical Isnes, Belgium). These have utilized a clear corneal entry, thereby sparing the conjunctiva. Early results with these ab-interno devices showed safety and efficacy in IOP-lowering that is similar to Schlemm’s canal minimally invasive glaucoma surgery devices and procedures. Despite the ab-interno approach, their long-term efficacy also seems to be limited by fibrosis. In addition, the first commercially available ab-interno suprachoroidal device, the CyPass Micro-Stent, has been voluntarily withdrawn globally by the manufacturer in August 2018, after 5-year follow-up data demonstrated a higher level of endothelial cell loss with the device than in controls. The iStent Supra and MINIject are not yet available commercially.

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