Forty-eight PACG patients(60 eyes)and 33 healthy people(33 eyes)were enrolled in this study. Ten eyes of PACG patients and 6 eyes of healthy subjects were excluded due to poor OCTA image quality. Therefore, 41 PACG patients (50 eyes) and 27 healthy subjects (27 eyes) were enrolled. Demographics and clinical characteristics of study subjects are listed in Table 1. The axial length of PACG eyes was significantly different from that of healthy eyes(p<0.001), and there were no significant differences in age, sex, intraocular pressure at examination and ocular perfusion pressure(p>0.05).The VF mean deviation in PACG eyes was −18.3±9.9db.
Table 1 Demographic and clinical characteristics of the study population
|
Healthy eyes(n=27)
|
PACG eyes(n=50)
|
P value
|
Gender(male/Female)
|
7:20
|
17:24
|
0.190*
|
Age(year)
|
61.9±7.6
|
62.3±7.9
|
0.843
|
SBP(mmHg)
|
137.6±12.3
|
135.6±20.6
|
0.877†
|
DBP(mmHg)
|
84.8±7.2
|
80.7±10.0
|
0.074†
|
OPP(mmHg)
|
57.4±6.8
|
54.1±9.7
|
0.162†
|
BCVA(log MAR)
|
0.6±0.2
|
0.5±0.2
|
0.163
|
IOP at imaging(mmHg)
|
13.9±2.9
|
15.1±3.7
|
0.087†
|
Al(mm)
|
23.6±0.9
|
22.4±1.1
|
<0.001†
|
VF MD(dB)
|
-
|
-18.3±9.9
|
-
|
PACG , primary angle closure glaucoma; SBP, systolic blood pressure; DBP, diastolic blood pressure; OPP, ocular perfusion pressure; BCVA, best-corrected visual acuity; IOP, intraocular pressure; AL, axial length; VF MD , visual field mean deviation
Unless otherwise illustrated, the comparison was made by using independent sample t test.
*The comparison was performed by using the chi-square test.
†The comparison was performed by using the Mann–Whitney test.
Table 2 shows data of peripapillary vessel density and RNFL thickness on the mean average, quadrant, and clock-hour regions. Compared with the control group, the peripapillary vessel density of glaucoma in all measured sectors decreased to different degrees and the difference was significant(P<0.05), with 7 o'clock decreased most. Except for 3 o'clock (P>0.05), peripapillary RNFL in all measured sectors showed significant difference between the glaucoma group and control group(P<0.05). Three o'clock sector was a less important sector in glaucomatous diagnosis. Fig 2 shows a decrease in infratemporal and supratemporal peripapillary vessel density sectors of glaucoma and atrophy of RNFL thickness in corresponding regions.
Table 2 Peripapillary retinal nerve fiber layer thickness and peripapillary vessel density in healthy and glaucomatous eyes
Parametres
|
RNFL thickness
|
Peripapillary vessel density
|
|
Healthy eyes(n=27)
|
PACG eyes(n=50)
|
P value
|
Healthy eyes(n=27)
|
PACG eyes(n=50)
|
P value
|
Average
|
113.0±9.6
|
78.3±26.1
|
<0.001*
|
54.8±2.5
|
46.0±5.6
|
<0.001*
|
Temporal
|
85.4±10.3
|
64.0±18.4
|
<0.001*
|
54.8±5.4
|
47.1±6.8
|
<0.001
|
Superior
|
142.7±19.2
|
92.9±38.2
|
<0.001*
|
57.3±2.7
|
48.5±6.6
|
<0.001*
|
Nasal
|
76.7±14.5
|
65.7±21.3
|
0.019
|
49.0±5.5
|
42.2±7.2
|
<0.001
|
Inferior
|
147.6±12.9
|
86.8±40.4
|
<0.001*
|
58.3±3.0
|
46.4±6.5
|
<0.001*
|
9
|
72.1±7.9
|
60.6±14.4
|
0.001*
|
50.3±7.1
|
46.4±6.6
|
0.018
|
10
|
100.1±14.0
|
69.0±26.6
|
<0.001*
|
58.4±4.9
|
49.5±7.7
|
<0.001*
|
11
|
148.3±24.8
|
91.2±42.1
|
<0.001*
|
59.2±3.6
|
47.9±8.9
|
<0.001*
|
12
|
144.8±30.8
|
98.2±43.2
|
<0.001
|
56.9±3.6
|
50.1±7.3
|
<0.001*
|
1
|
135.1±23.5
|
89.1±37.5
|
<0.001*
|
55.9±3.9
|
47.8±6.9
|
<0.001*
|
2
|
90.9±22.2
|
75.4±28.8
|
0.018
|
51.0±5.9
|
44.4±8.4
|
0.001*
|
3
|
66.7±14.5
|
60.4±19.1
|
0.137
|
46.7±7.0
|
40.6±8.1
|
0.001
|
4
|
72.5±12.0
|
60.2±22.8
|
0.003*
|
49.5±5.0
|
41.3±8.4
|
<0.001*
|
5
|
123.1±16.2
|
86.2±38.1
|
<0.001*
|
55.7±4.7
|
44.7±7.9
|
<0.001*
|
6
|
157.9±20.1
|
102.5±46.8
|
<0.001*
|
58.7±4.1
|
49.0±6.9
|
<0.001*
|
7
|
161.3±25.8
|
82.5±43.2
|
<0.001*
|
60.4±4.7
|
45.3±8.8
|
<0.001*
|
8
|
82.7±17.0
|
62.0±19.9
|
<0.001*
|
55.2±6.4
|
45.5±8.1
|
<0.001
|
RNFL, retinal nerve fiber layer; PACG , primary angle closure glaucoma
Unless otherwise illustrated, the comparison was made by using independent sample t test.
*The comparison was performed by using the Mann–Whitney test.
AUCs of peripapillary vessel density was between 0.658 in 9 o'clock sector and 0.944 in the inferior quadrant. AUCs of RNFL thickness was between 0.596 in 3 o'clock sector and 0.922 in 7 o'clock sector. Inferior quadrant vessel density had the highest diagnostic ability (AUCs0.944), followed by 7 clock-hour peripapillary vessel density (AUCs0.937), average vessel density (AUCs0.926) and 7 o'clock RNFL thickness (0.922). Except 4 o'clock, there was no statistical difference between the diagnostic ability of peripapillary vessel density and RNFL. The diagnostic ability of 4 o'clock vessel density was higher than that of RNFL (Table 3).
Table 3 Areas under the receiver operating characteristics curves comparison for glaucomatous discrimination ability between Peripapillary vessel density and RNFL thickness
|
Control and glaucomatous eyes
|
|
Parametres
|
Peripapillary vessel density
|
RNFL thickness
|
P value
|
Optic disc
|
AUC
|
95%CI
|
AUC
|
95%CI
|
Average
|
0.926
|
0.844-0.973
|
0.885
|
0.792-0.947
|
0.265
|
Temporal
|
0.814
|
0.709-0.893
|
0.832
|
0.729-0.907
|
0.727
|
Superior
|
0.880
|
0.786-0.943
|
0.859
|
0.760-0.927
|
0.655
|
Nasal
|
0.769
|
0.659-0.857
|
0.664
|
0.548-0.768
|
0.054
|
Inferior
|
0.944
|
0.866-0.983
|
0.904
|
0.815-0.959
|
0.290
|
9
|
0.658
|
0.541-0.762
|
0.739
|
0.626-0.832
|
0.235
|
10
|
0.834
|
0.732-0.909
|
0.843
|
0.743-0.916
|
0.848
|
11
|
0.875
|
0.780-0.939
|
0.877
|
0.782-0.941
|
0.968
|
12
|
0.796
|
0.688-0.879
|
0.810
|
0.705-0.890
|
0.801
|
1
|
0.834
|
0.732-0.909
|
0.856
|
0.757-0.925
|
0.667
|
2
|
0.735
|
0.622-0.829
|
0.673
|
0.557-0.776
|
0.202
|
3
|
0.714
|
0.600-0.812
|
0.596
|
0.478-0.706
|
0.074
|
4
|
0.811
|
0.705-0.891
|
0.675
|
0.558-0.777
|
0.022
|
5
|
0.881
|
0.788-0.944
|
0.814
|
0.710-0.894
|
0.161
|
6
|
0.881
|
0.787-0.943
|
0.837
|
0.735-0.911
|
0.332
|
7
|
0.937
|
0.857-0.979
|
0.922
|
0.838-0.971
|
0.676
|
8
|
0.825
|
0.721-0.902
|
0.787
|
0.679-0.872
|
0.487
|
RNFL, retinal nerve fiber layer; AUCs, areas under the receiver operating characteristics curves; CI, confidence interval;
IOP, average RNFL thickness and VF mean deviation were correlated with average peripapillary vessel density. The P value of IOP was close to 0.05, indicating that the correlation between average peripapillary vessel density and average RNFL ,VF mean deviation were stronger than any other variables (Table 4).
Table 4 The correlation between peripapillary vessel density and glaucomatous related factors
|
Peripapillary vessel density
|
|
r
|
P
|
Age(year)
|
-0.170
|
0.238
|
Sex
|
0.041
|
0.863
|
IOP(mmHg)
|
-0.318
|
0.024*
|
Mean OPP(mmHg)
|
0.141
|
0.329
|
RNFLthickness(μm)
|
0.750
|
<0.001
|
VF MD(dB)
|
0.749
|
<0.001*
|
IOP, intraocular pressure;OPP, ocular perfusion pressure; RNFL, retinal nerve fiber layer; VF MD , visual field mean deviation
Unless otherwise illustrated, correlation analysis was made by using Pearson correlation test.
* Correlation analysis was made by using Spearman correlation test.