Interaction of intraocular pressure and ganglion cell function in open angle glaucoma

PurposeTo test the feasibility of simultaneous steady-state pattern electroretinogram (PERG) and intraocular pressure (IOP) measurements with an IOP sensor and to test a model for IOP manipulation during lateral decubitus positioning (LDP) and its impact on the PERG. DesignA prospective, observational study. Methods15 healthy controls and 15 treated glaucoma patients participated in the study. 8 patients had an intraocular IOP sensor (eyemate-IO(R), Implandata Ophthalmic Products GmbH) in the right eye (GLAIMP) and 7 had no sensor and with glaucoma in the left eye. (1) We tested the feasibility of simultaneous IOP and PERG recordings by comparing PERGs with and without simultaneous IOP-read out in GLAIMP. (2) All participants were positioned in the following order: sitting1 (S1), right LDP (LDR), sitting2 (S2), left LDP (LDL) and sitting3 (S3). For each position, PERG amplitudes and IOP were determined with rebound tonometry (Icare(R) TA01i) in all participants without the IOP sensor. ResultsElectromagnetic intrusions of IOP sensor readout onto steady-state PERG-recordings had, due to different frequency ranges, no relevant effect on PERG amplitudes. IOP and PERG measures were affected by LDP, e.g., IOP was increased during LDR vs S1 in the lower eyes of GLAIMP and controls (P < 0.001 and P < 0.05, respectively) and PERG amplitude was decreased (P < 0.05 and P < 0.01, respectively). ConclusionsDuring LDP, IOP and PERG measurements changed more in the lower eye. IOP changes induced by LDP may be a model for studying the interaction of IOP and ganglion cell function.