Preliminary Report of the Association of Pulsatile Translaminar Pressure Gradient with Glaucomatous Damage

Abstract

 

Purpose

 

To evaluate the influence of Ocular Pulse Amplitude (OPA) on the translaminar pressure gradient and its association with glaucomatous damage. Translaminar pressure gradient is defined as intraocular pressure (IOP) minus intracranial pressure (ICP).

 

Methods

 

To date, 7 subjects in four groups have been prospectively enrolled: 1 ocular hypertension (OHT), 2 primary open angle glaucoma (POAG), 2 normal tension glaucoma (NTG), and 2 normal (NRM) control. Data acquisition includes Goldmann Applanation Tonometry (GAT), PASCAL Dynamic Contour Tonometry (DCT), Optical Response Analyzer (ORA), CorVis ST, Galilei Dual-Scheimpflug Analysis, Optical Coherence Tomography (OCT), Heidelberg Retinal Tomography (HRT), Humphrey visual field, blood pressure, and slit lamp examination. A lumbar puncture (LP) was then performed in the lateral decubitus position, under ultrasound guidance with a 27 gauge pencil point needle and an electronic transducer to record cerebrospinal fluid (CSF) waveform as a surrogate for ICP. A survey was conducted 3 days post-LP to assess presence of post dural puncture headache and/or other symptoms. CSF waveforms were compared to ocular pulse waveforms for analysis between groups.

 

Results

 

One subject from each group is shown in Figure 1. Note that both subjects with glaucoma were treated, and thus both IOP and OPA are expected to be lower during study measurements than on initial presentation. Subject in OHT group was not treated. The lowest mean but highest peak to valley amplitude in the translaminar pressure gradient was in the POAG subject. Figure 2 highlights peak to valley amplitudes in translaminar gradient with CSF pressure adjusted to IOP. No LP-related complications were reported at 3 days following procedure.

 

Conclusions

 

Although enrollment is too low to draw definitive conclusions, early results indicate that differences may exist in the magnitude of the pulsatile component of the translaminar pressure gradient between groups, with greater magnitude of translaminar pulsations associated with glaucomatous damage. Future subjects will have IOP and CSF pressure waveforms recorded simultaneously to allow direct subtraction. Recruitment is ongoing.

 

 

IOP (solid lines) and CSF pressure (dotted lines) of subjects with OHT (blue), NRM (green), NTG (yellow) and POAG (red).

 

 

Peak to Valley differences are highlighted by adjusting CSF to IOP value for subtraction of one cycle.

 

Keywords: 568 intraocular pressure • 577 lamina cribrosa