Authors:
Seongmin Im
1
;
Jaeyong An
1
;
Jongchan Choi
1
;
Byungphil Mun
1
;
Sung Yang
2
and
Jonghyun Lee
2
Affiliations:
1
School of Mechatronics and Gwangju Institute of Science and Technology, Korea, Republic of
;
2
School of Mechatronics; Graduate Program of Medical System Engineering; Gwangju Institute of Science and Technology, Korea, Republic of
Keyword(s):
Glaucoma drainage device, Polymer, Check Valve, Selectively bonding, Intraocular Pressure, FEA, MEMS.
Related
Ontology
Subjects/Areas/Topics:
Biomechanical Devices
;
Biomedical Engineering
;
Biomedical Instrumentation
;
Biomedical Instruments and Devices
;
Hardware
;
MEMS
;
Sensor Networks
Abstract:
A glaucoma drainage device for the regulation of intraocular pressure is presented. The device consists of three biocompatible polymer layers: the cover (top layer), the diaphragm (intermediate layer), and the baseplate with a cannular (bottom layer). Finite element analyses (FEA) were performed to find optimal design parameters for the targeted cracking pressure: the diameter of orifice, the thickness of intermediate layer, the width of the channel, and the overlapped length of the orifice over valve seat. Top and bottom layers were made by polydimethylsiloxane (PDMS) replica molding process, and an intermediate thin layer with through-holes was fabricated by PDMS fill-in molding method and hydrophobic treatment. The overlapped area of the bottom layer was coated with Cr and Au by using PDMS as a shadow mask. Metal layers are not to be bonded between the bottom and the intermediate layers so that the device showed the enhanced reliability in operation and the higher yield in product
ion. Oxygen plasma treatment was performed for irreversible bonds between separate three PDMS layers. The experimental cracking pressure of the fabricated valve was 2.50 kPa, which is very close to the target value (2.67 kPa). The experiments showed that the proposed polymer check valve can regulate the pressure of the aqueous humour, fluid in an anterior chamber, within the normal intraocular pressure range (15~20mmHg) with a high repeatability.
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