Abstract:

 Objective To investigate abnormalities of nailfold microcirculation in patients with primary open angle glaucoma (POAG).  Design Prospective comparative case series.  Participants 51 patients with POAG (POAG group) including 34 patients with high tension glaucoma (HTG group) and 17 patients with normal tension glaucoma (NTG group) diagnosed in Beijing Tongren Hopistal and 70 normal healthy subjects (control group). Methods  Nailfold capillaroscope (JH-1004 microscope) was used to examine the fourth digit of nondominant hand of each subject. The hemorrhages of nail fold capillaries were observed. Capillary density, avascular zone (distance in proximal area of two capillaries), arterial limb diameter and venous limb diameter of capillaries (the widest diameter of limb) were measured.  Case number and score of avascular zones>200 μm, capillary hemorrhages, dilated capillaries (a capillary with arterial limb wider than 15 μm or with venous limb wider than 20 μm) were analyzed. We coded nailfold microcirculation into 4 categories according to the severity respectively. (e.g., 0 for no dilated capillary, 1 for 1 dilated capillary category, 2 for 2 dilated capillary categories, 3 for 3 or more dilated capillary categories). Main Outcome Measures  Nailfold capillary density, number of cases of avascular zones > 200 μm, hemorrhages, dilated capillaries and severity score of abnormal conditions. Results The capillary density of HTG group, NTG group and control group were 9(9,10),10(9,10) and 10(9,10) ( χ2=4.123, P=0.127). The subjects with avascular zones in HTG group, NTG group and control group were 20(58.8%), 8(47.1%) and 27(38.6%) (χ2=3.894, P=0.143). The subjects with hemorrhages in HTG group, NTG group and control group were 15(44.1%), 6(35.3%) and 18(25.7%) (χ2=3.633, P=0.163). The subjects with dilated capillaries in HTG group, NTG group and control group were 18(52.9%),7(41.2%)and 21(30.0%) (χ2=5.195, P=0.074). The difference between POAG and control group was significant ( χ2=4.492, P=0.034). The severity score of avascular zones in HTG group, NTG group and control group were 1(0,1.25), 0(0,1) and 0(0,1) (χ2=3.842, P=0.146). The severity score of hemorrhages in HTG group, NTG group and control group were 0(0,1), 0(0,1) and 0(0,1) (χ2=3.156, P=0.206). The severity score of dilated capillaries in HTG group, NTG group and control group were 1(0,2), 0(0,1) and 0(0,1) (χ2=8.125, P=0.017). There is significant difference between HTG and control group (Z=-2.904, P=0.004).  Conclusion  The dilated capillaries in nailfold capillaroscopy are more frequent in POAG patients with the higher severity of dilated capillaries in HTG, which implied that microcirculation abnormalities may play a role in the pathogenesis of POAG. There is no significant difference of nailfold microcirculation between HTG and NTG. The reasons may involve the limited sample size and indicators about nailfold microcirculation. (Ophthalmol CHN, 2019, 28: 17-23)

Key words: primary open angle glaucoma, nailfold capillary