Biostatistical evidence for two distinct chronic open angle glaucoma populations

Area of Science:

• Ophthalmology
• Vascular Biology
• Medical Diagnostics

Background:

• Glaucoma is an optic neuropathy often associated with elevated intraocular pressure.
• However, distinct pathophysiological mechanisms may underlie low-tension glaucoma (LTG) and high-tension glaucoma (HTG).
• Understanding these differences is crucial for targeted treatment strategies.

Purpose of the Study:

• To investigate potential distinct pathophysiological profiles in patients with low-tension glaucoma and high-tension glaucoma.
• To identify correlations between clinical parameters and underlying vascular or rheological factors.

Main Methods:

• A cohort of 26 LTG eyes and 34 HTG eyes were analyzed.
• Fifty-one measurements were collected per patient, including visual field indices (e.g., mean deviation), finger blood flow, and hematological, coagulation, biochemical, and rheological variables.
• Multivariate analysis was employed to identify distinct patient subgroups.

Main Results:

• Multivariate analysis identified two distinct patient groups, irrespective of initial glaucoma tension classification.
• A smaller group (15 patients) exhibited vasospastic finger blood flow and a significant positive correlation between mean deviation (MD) and highest intraocular pressure (IOP) (r = 0.715, p = 0.0008).
• A larger group (45 patients) displayed disturbed coagulation and biochemical markers, suggesting underlying vascular disease, with no correlation between MD and IOP.

Conclusions:

• Glaucoma patients can be categorized into at least two distinct pathophysiological groups based on vascular and rheological assessments.
• One group is characterized by vasospasm and a direct relationship between visual field severity and IOP.
• The other group shows markers of systemic vascular disease and a dissociation between visual field damage and IOP.