Comparison of two prototypes of a magnetically adjustable glaucoma implant in rabbits
Creators: name: Schwerk, Birthe
name: Harder, Lisa
name: Windhövel, Claudia
name: Hewicker-Trautwein, Marion
name: Wagner, Anna
name: Bach, Jan-Peter
name: Voigt, Lena Carolin
name: Hinze, Ulf
name: Chichkov, Boris
name: Haferkamp, Heinz
name: Lubatschowski, Holger
name: Nikolic, Stephan
name: Nolte, Ingo
Publisher: name: San Francisco, CA : Public Library of Science (PLoS)
Year: 2019
Subjects: subject: dexamethasone
subject: meloxicam
subject: neomycin
subject: polymyxin
subject: animal cell
subject: animal experiment
subject: animal model
subject: Article
subject: biocompatibility
subject: blepharospasm
subject: controlled study
subject: disease severity
subject: erythema
subject: eye inflammation
subject: eye swelling
subject: female
subject: foreign body reaction
subject: geometry
subject: histology
subject: hyperemia
subject: implantation
subject: in vivo study
subject: intraocular hemorrhage
subject: intraocular hypotension
subject: intraocular pressure
subject: iris disease
subject: iris hyperemia
subject: Leporidae
subject: lymphocyte
subject: macrophage
subject: magnetically adjustable glaucoma implant
subject: New Zealand White (rabbit)
subject: nonhuman
subject: ocular fibrosis
subject: operation duration
subject: ophthalmoscopy
subject: pilot study
subject: slit lamp microscopy
subject: thickness
subject: tonometry
subject: Dewey Decimal Classification::500 | Naturwissenschaften
subject: Dewey Decimal Classification::600 | Technik::610 | Medizin, Gesundheit

description: Glaucoma drainage devices are used in surgical glaucoma therapy. Success of controlling the intraocular pressure is limited due to fibrous implant encapsulation and fibrin coating on the implant which lead to drainage obstructions. An innovative implant with a magnetically adjustable valve was developed. The valve opening of the implant should eliminate inflammatory products from the outflow area and affect fibrous tissue formation to achieve a sufficient long-term aqueous humour outflow. Lifting of this valve should disturb cell adhesion by exerting mechanical forces. Before testing this hypothesis, the flow characteristics of glaucoma drainage devices, especially the outflow resistance by regular IOP, should be considered in a pilot study, as they are important in preventing too low postoperative intraocular pressure known as ocular hypotony. Therefore, two prototypes of the innovative implant differing in their valve area design were examined regarding their flow characteristics in a limited animal experiment lasting two weeks. Ten healthy New Zealand White rabbits were divided into two groups (A &amp; B) with different implanted prototypes. Daily, tonometry and direct ophthalmoscopy were performed to assess the intraocular pressure and the inflammatory reaction of the eye. After two weeks, the rabbits were euthanised to evaluate the initially histological inflammatory reaction to the implant. In group A, one case of hypotony emerged. When considering the entire observation period, a highly statistically significant difference between the intraocular pressure in the operated eye and that in the control eye was detected in group A (p &lt; 0.0001) in contrast to group B (p = 0.0063). The postoperative inflammatory signs decreased within two weeks. Histologically, a typical but low level foreign body reaction with macrophages and lymphocytes as well as mild to moderate fibrosis was seen after the short experimental period. Based on our tonometric results, prototype B seems to be the system of choice for further research assessing its long-term function and biocompatibility.