A recent prospective study published in Diagnostics found further evidence connecting lowered intracranial pressure (ICP) to the development of normal-tension glaucoma (NTG).
Give me some background.
Researchers have recently focused on the potential role of ICP and translaminar pressure difference (TPD) in glaucomatous optic neuropathy.
While conflicting data exists about the influence of ICP on NTG and visual field (VF) changes, overall, the literature largely supports the impact of reduced ICP in the development and progression of glaucoma.
What’s the connection to this study?
In this study, investigators sought to assess the relationship between ICP and VF zones in patients diagnosed with NTG.
Tell me about it.
The study included 80 subjects (average age of 59.5; 24% male) with early-stage NTG. Each participant was selected from the 300 NTG patients referred to the Eye Clinic at the Lithuanian University of Health Sciences between January and October 2018, and were evaluated for inclusion based on IOP (Goldmann), visual perimetry (Humphrey), and non-invasive ICP.
The VFs of each patient were divided into five zones: nasal, temporal, peripheral, central, and paracentral. The average pattern deviation (PD) scores were calculated in each zone.
Investigators used a novel method of a non-invasive ICP measurement technology—created by investigator Arminas Rgauskas, a professor at the Kaunas University of Technology, Lithuania—with a two-depth Transcranial Doppler diagnostic tool to measure the ICP of each patient.
What did they find?
The study identified a mean ICP value of 8.5 (2.4) mmHg in NTG patients. A higher translaminar pressure difference (TPD) was associated with lower mean deviation (p = 0.01) and higher pattern standard deviation (p = 0.01).
Anything else?
ICP was significantly related with the lowest averaged pattern deviation scores in the nasal VF zone (p < 0.001). No significant correlations were recorded between ICP and other VF zones with the most negative mean PD value (p > 0.05).
The take home.
While the study shows the potential of using higher TPD (or, based on the formula, lowered ICP) to estimate risk level and categorization, the authors noted that more research is needed to understand the pathophysiological connection between ICP and glaucoma, specifically as a biomarker for NTG.