Quantification of Retinal Microvascular Density Using Optic Coherence Tomography Angiography in Primary Angle Closure Disease

ABSTRACT

Purpose: To evaluate the microvascular density of the peripapillary and parafoveal areas of the eyes with primary angle closure disease (PACD) using optical coherence tomography angiography (OCTA).

Materials and methods: An observational study was conducted with 76 PACD patients (29 eyes with primary angle closure suspect, 22 eyes with primary angle closure [PAC], and 25 eyes with primary angle closure glaucoma [PACG]) and 27 control eyes. OCTA was performed for all subjects to acquire a 4.5 × 4.5 mm scanning area centered on the optic discs and a 3 × 3 mm parafoveal cubes. Peripapillary and parafoveal vessel density (VD) were compared between these four groups, and the relationship between VD values and structural and functional changes was evaluated.

Results: Among all four groups, the peripapillary VD of the PACG eyes was the lowest in all six sections (all P < .01), while the parafoveal VD was lower than that of the normal group only in the average, superior, and inferior areas (all P < .05). The PAC group had lower peripapillary VD than the normal group (62.6[55.2–67.4] vs. 66.7[54.7–69.3], P = .01), while their retinal nerve fiber layer (RNFL) and ganglion cell complex thickness were not significantly different than those of the control group (all P > .05). In addition, the stages of PACD, visual field mean deviation, and RNFL thickness were shown to be predictors of the peripapillary VD in the multiple linear regression analysis.

Conclusions: The PAC eyes had lower peripapillary VD than normal eyes when their RNFL and GCC thickness did not differ. This suggests that a reduction in retinal VD may occur before structural loss in PAC eyes. Retinal VD measurement may be a useful tool for the assessment of PACD.

KEYWORDS:

• Peripapillary vessel density
• parafoveal vessel density
• primary angle-closure disease
• optical coherence tomography angiography
• primary angle closure glaucoma

Declaration of interest statement

The authors declare that they have no competing interests. The authors alone are responsible for the contest and writing of the paper. 


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Funding

This research project was supported by the State Key Program of National Natural Science Foundation of China [81430007], the subject of major projects of National Natural Science Foundation of China [81790641], National Natural Science Foundation of China [81870661], the Shanghai Committee of Science and Technology, China [17410712500], the Shanghai Shenkang Hospital Development Center Clinical Science and Technology Innovation project [SHDC12018110], and the top priority of clinical medicine center of Shanghai [2017ZZ01020]. The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.