AIM: To investigate the difference of the optic vessel density in early primary open angle glaucoma(POAG), ocular high tension subjects and healthy subjects.

METHODS: A cross-sectional study. From January 2019 to April 2021, patients were selected in the Department of Glaucoma in Fuzhou Southeast Eye Hospital. There were 45 patients(70 eyes)of early POAG group, including 32 males(49 eyes)and 13 females(21 eyes)with age of 48.50(26.75, 64.50)years. There were 37 patients(65 eyes)of ocular high tension group, including 17 males(29 eyes)and 20 females(36 eyes)with age of 37.00(27.00, 47.00)years. There were 51 patients(94 eyes)of healthy group, including 23 males(39 eyes)and 28 females(55 eyes)with age of 46.00(34.50, 56.50)years. Ophthalmic examinations including best-corrected visual acuity(BCVA), intraocular pressure, central corneal thickness(CCT), mean deviations(MD), retinal nerve fiber layers thickness(RNFL)were measured in three groups. The center area, the inner circle area, the outer circle area, and the whole area of the optic vessel density in three groups were measured via optical coherence tomography angiography(OCTA)device.

RESULTS: The difference of the intraocular pressure in early POAG group-ocular high tension group was not significant(H=146.876,P<0.001), while significantly in early POAG group-healthy group and ocular high tension group-healthy group(all P<0.01). Significant differences in BCVA, MD, and RNFL were observed in early POAG group-ocular high tension group(P=0.005, P=0.01, P<0.01)and early POAG group-healthy group(P=0.013, P<0.01, P<0.01), while the difference was not found in ocular high tension group-healthy group(P=1.000, P=0.660, P=1.000). There was no difference of CCT in early POAG group-healthy group(P=0.074), and significant differences were observed in early POAG group-ocular high tension group and ocular high tension group-healthy group(P=0.006, P<0.01). The optic vessel density comparison in the center area, the inner circle area, and the whole area were significantly different in early POAG group-ocular high tension group(all P<0.01)and in early POAG group-healthy group(all P<0.01), which indicated that the optic vessel density was obviously less in the early POAG group than the other two groups. The optic vessel density had no significant difference in ocular high tension group-healthy group in these areas(all P=1.000). In the outer circle area, there were no significant differences of the optic vessel density in early POAG group-ocular high tension group and early POAG group-healthy group(P=0.067, P=0.877), while significant difference was observed in early POAG group-healthy group(P=0.001).

CONCLUSION: The optic vessel density was decreased in early POAG comparing with ocular high tension subjects and healthy subjects, which was agree with the changes of MD, RNFL. The optic vessel density decreased firstly from the center area and the inner circle area for early POAG.