Correlation of Visual Field With Peripapillary Vessel Density Through Optical Coherence Tomography Angiography in...

Area of Science:

• Ophthalmology
• Medical Imaging
• Glaucoma Research

Background:

• Normal-tension glaucoma (NTG) is a progressive optic neuropathy characterized by visual field defects despite normal intraocular pressure.
• Assessing structural and functional changes in NTG is crucial for early diagnosis and management.
• Optical coherence tomography angiography (OCTA) offers high-resolution imaging of retinal microvasculature.

Purpose of the Study:

• To investigate retinal vessel density (VD) in healthy and NTG eyes using OCTA.
• To determine the correlation between VD and retinal nerve fiber layer (RNFL) thickness and visual field (VF) defects in NTG.
• To compare the diagnostic utility of VD versus RNFL thickness in different stages of NTG.

Main Methods:

• A study included 74 NTG eyes and 24 healthy eyes.
• OCTA was used to measure peripapillary and macular VD.
• RNFL thickness and VF data were analyzed and correlated with VD using sector-based analysis.

Main Results:

• NTG eyes showed significantly lower peripapillary VD, macular VD, RNFL thickness, and ganglion cell complex thickness.
• Anatomic correlations between VD and VF defects were stronger in the peripapillary region, especially the inferotemporal sector, compared to RNFL thickness and VF correlations.
• VD correlated with VF defects across all stages of NTG, while RNFL thickness correlated only in moderate to severe stages.

Conclusions:

• Retinal VD is reduced in the peripapillary and macular areas of NTG eyes.
• Peripapillary microvascular dropout, assessed by VD, shows a more accurate anatomic correlation with functional VF defects than RNFL thickness, particularly in early NTG.
• VD measurement is a valuable tool for detecting NTG, especially in patients unable to complete VF examinations.