Jianbo Zhou1, Gregory T Smedley. 1. Research & Development, Glaukos Corporation, Laguna Hills, California 92653, USA. jzhou@glaukos.com
Abstract
PURPOSE: To introduce a hypothesis that theorizes the effect of a trabecular bypass, a channel created through the trabecular meshwork, on the facility of outflow and the intraocular pressure (IOP). METHODS: Equations that govern the pressure and circumferential flow in Schlemm's canal are established, based on the linear relationships between pressure drop and flow, the balance of flows in the canal, and a uniform leaking structure of collector channels. Two types of bypasses permitting either unidirectional or bidirectional flow are incorporated through boundary conditions to solve the equations and to derive the facility of outflow and the reduced IOP. RESULTS: In normal healthy eyes, the facility of outflow increases by 13% and 26% in the presence of a unidirectional and bidirectional bypass, respectively. The circumferential flow is significant only in the immediate quadrant to the bypass. The elevated IOP due to the abnormally high resistance in trabecular meshwork in open angle glaucoma is substantially reduced with a single bypass. Mean physiological level of IOP is attained if the bidirectional bypass is placed; slightly higher IOP is attained if a unidirectional bypass is placed. In either case, the higher the baseline IOP, the greater the reduction. The effectiveness of the bypass on IOP reduction is related to the resistances in the canal and the collector channels. Multiple bypasses can be used to further reduce the IOP. CONCLUSION: It is theoretically demonstrated that a single patent trabecular bypass can enhance the facility of outflow and reduce the IOP to physiological levels.
PURPOSE: To introduce a hypothesis that theorizes the effect of a trabecular bypass, a channel created through the trabecular meshwork, on the facility of outflow and the intraocular pressure (IOP). METHODS: Equations that govern the pressure and circumferential flow in Schlemm's canal are established, based on the linear relationships between pressure drop and flow, the balance of flows in the canal, and a uniform leaking structure of collector channels. Two types of bypasses permitting either unidirectional or bidirectional flow are incorporated through boundary conditions to solve the equations and to derive the facility of outflow and the reduced IOP. RESULTS: In normal healthy eyes, the facility of outflow increases by 13% and 26% in the presence of a unidirectional and bidirectional bypass, respectively. The circumferential flow is significant only in the immediate quadrant to the bypass. The elevated IOP due to the abnormally high resistance in trabecular meshwork in open angle glaucoma is substantially reduced with a single bypass. Mean physiological level of IOP is attained if the bidirectional bypass is placed; slightly higher IOP is attained if a unidirectional bypass is placed. In either case, the higher the baseline IOP, the greater the reduction. The effectiveness of the bypass on IOP reduction is related to the resistances in the canal and the collector channels. Multiple bypasses can be used to further reduce the IOP. CONCLUSION: It is theoretically demonstrated that a single patent trabecular bypass can enhance the facility of outflow and reduce the IOP to physiological levels.
Authors: Jens F Jordan; Thomas Wecker; Christian van Oterendorp; Alexandra Anton; Thomas Reinhard; Daniel Boehringer; Matthias Neuburger Journal: Graefes Arch Clin Exp Ophthalmol Date: 2013-10-26 Impact factor: 3.117