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

Abstract

Purpose:To 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. Design:A prospective, observational study.Methods: 15 healthy controls and 15 treated glaucoma patients participated in the study. 8 patients had an intraocular IOP sensor (eyemate-IO ® , 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® TA01i) in all participants without the IOP sensor.Results: Electromagnetic intrusions of IOP sensor readout onto steady-state PERGrecordings 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). Conclusions:During 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.

Diagnostic performance of multifocal photopic negative response, pattern electroretinogram and optical coherence tomography in glaucoma

“…Only PERG 0.8° amplitude and PERG ratio (small/big checksizes’ amplitudes) were used for analysis. Further description of analysis is mentioned elsewhere(Bach and Hoffmann 2008; Preiser et al 2013; Al-Nosairy et al 2020).…”

Implanted Microsensor Continuous IOP Telemetry Suggests Gaze and Eyelid Closure Effects on IOP—A Preliminary Study

“…In the present study, continuous communication between sensor and reader device was established by means of an external antenna attached to the reader and placed around the patient's sensor eye, not touching the eyelids. A figure of the antenna placement around the eye has been published by Al-Nosairy et al 28 In this configuration, data acquisition was possible for a maximum of two hours at a sampling rate of approximately 9 Hz.…”

“…Interestingly, the same patient group demonstrated a more homogenous IOP response to changes in body position in another study. 28 It is possible that IOP responses during ocular movements are more subjectdependent than for other influencing factors such as body posture. Because more patients will likely be implanted with the Eyemate, it will be easier to investigate short-term IOP variability in response to various external stimuli, as well as physiological parameters in future studies.…”

Combined multi-modal assessment of glaucomatous damage with electroretinography and optical coherence tomography/angiography

“…The pupils were dilated only for the mfPhNR recordings. Further details on the procedure and recording, analysis of mfPhNR and ssPERG are given in (Al-Nosairy et al 2020, Al-Nosairy, Thieme & Hoffmann 2020, Preiser et al 2013). Only the ssPERG 0.8° amplitude (ssPERG amplitude) and averaged mfPhNR/b-wave ratio (mfPhNR ratio) were compared to the acquired vascular and structural parameters.…”