UC Irvine

Background/aims

To investigate the relationship between the foveal avascular zone (FAZ) parameters assessed by optical coherence tomography angiography (OCTA) and central visual field parameters in glaucoma and healthy subjects.

Methods

One hundred and eighty-eight subjects (248 eyes), including 24 healthy (38 eyes), 37 glaucoma suspect (42 eyes, and 127 primary open angle glaucoma (POAG) patients (168 eyes), underwent imaging using OCTA and standard automated perimetry using the 24-2 and 10-2 Swedish Interactive Thresholding Algorithm. OCTA-based and OCT-based FAZ parameters (superficial FAZ area, FAZ circumference), foveal vessel density (FD300) and foveal thickness were measured. The correlation between FAZ parameters and visual field parameters was assessed using linear mixed model.

Results

Axial length adjusted-FAZ area was not different among the three groups (mean (95% CI)): in healthy 0.31 (0.27 to 0.36) mm², glaucoma suspect 0.29 (0.26 to 0.31) mm² and POAG eyes 0.28 (0.27 to 0.30) mm² (p=0.578). FD300 was lower in glaucoma suspect 49.1% (47.9% to 50.4%) and POAG eyes 48.7% (48.1% to 49.4%) than healthy eyes 50.5% (49.3% to 51.7%) though the difference was not statistically significant (p=0.071). Lower FD300 was associated with worse 24-2 and 10-2 visual field mean deviation and foveal threshold in multivariable linear mixed models (all p<0.05). In addition, a smaller FAZ area was associated with lower intraocular pressure (IOP) (p=0.026).

Conclusions

The FD300, but not the FAZ area was correlated with 10° central visual field mean deviation and foveal threshold in healthy, glaucoma suspect and POAG eyes. In contrast, a smaller FAZ area was associated with lower IOP.