Steeper structure-function relationship in eyes with than without a parapapillary deep-layer microvasculature...

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Visual field (VF) loss in glaucoma shows significant variability relative to retinal nerve fiber layer (RNFL) thickness.
• The underlying reasons for this structure-function relationship variability remain unclear.
• Choroidal microvasculature dropout (MvD) is a potential factor influencing glaucoma progression.

Purpose of the Study:

• To investigate the impact of choroidal microvasculature dropout (MvD) on the structure-function relationship in primary open-angle glaucoma (POAG).
• To compare visual field sensitivity and RNFL thickness in POAG patients with and without MvD.

Main Methods:

• Cross-sectional study comparing 71 POAG patients with MvD (MvD+ group) to 71 age- and inferotemporal (IT) RNFL thickness-matched POAG patients without MvD (MvD- group).
• MvD presence was determined using optical coherence tomography angiography.
• Visual field sensitivity was averaged for the IT RNFL sector using total and pattern deviation maps.

Main Results:

• The slope of log-scale RNFL thickness versus VF defect was significantly steeper in the MvD+ group compared to the MvD- group (P=0.004 for total deviation, P<0.001 for pattern deviation).
• Both total and pattern VF deviation were significantly worse in the MvD+ group (P=0.002 and P=0.007, respectively).
• These findings were consistent across subgroups with thick and thin RNFL thickness.

Conclusions:

• Parapapillary MvD is associated with a poorer function of remaining retinal axons in POAG.
• MvD may contribute to the observed variability in visual field loss at a given RNFL thickness.
• Further research into MvD's role in glaucoma pathogenesis is warranted.