Effects Of Severe Carotid Artery Stenosis On Ocular Blood Flow And Visual Function

Objectives To investigate the effects of severe carotid stenosis on ocular blood flow and visual function,and to evaluate the changes in ocular blood flow and visual function before and after surgical treatment of carotid stenosis,with emphasis on assessing changes in blood flow in all layers of the retina.Methods A total of 22 patients,44 eyes,with unilateral severe internal carotid artery stenosis,who were hospitalized in the Department of Vascular Surgery of the Hebei Ge neural Hospital from March 2021 to December 2021 without obvious ocular symptoms,were selected and divided into two groups: the operated eye and the contralateral eye.All subjects underwent carotid ultrasound and CT angiography(CTA)to clarify the degree of internal carotid artery stenosis before enrollment,and all subjects’ basic conditions(including personal and past histories,etc.)were counted.Contrast sensitivity(CS),best corrected visual acuity(BCVA),intraocular pressure(IOP),optical coherence tomography(OCT)and optical coherence tomography angiography(OCTA)were performed before and one week after the surgical treatment of internal carotid artery stenosis in both the operated eye and the contralateral eye.Visual function was observed in both groups: CS and BCVA;retinal and choroidal structures were assessed by OCT: mean retinal thickness(RT),mean choroidal thickness(CT),ganglion cell complex layer(GCC),and peripapillary retinal nerve fiber layer(RNFL);OCTA assessment of retinal and choroidal blood flow: vascular density of superficial capillary plexus(SCP),deep capillary plexus(DCP),choriocapillaris(CC),radial peripapillary capillary(RPC)and the area,perimeter and circularity of the foveal avascular zone(FAZ)in the central macular recess.To evaluate the changes in ocular blood flow and visual function in patients with severe internal carotid artery stenosis before and after surgical treatment.Results 1 Before surgical treatment,there was no statistically significant difference in CS,BCVA and IOP between the operated eye and the contralateral eye in patients with unilateral severe internal carotid artery stenosis(all P>0.05).The CS(Z=-2.001,P=0.045)in the operated side of the eye after surgical treatment improved compared to preoperative,BCVA and IOP were not significantly changed from preoperative(all P>0.05).The CS(Z=-2.471,P=0.013)in the contralateral eye improved compared to the preoperative,BCVA and IOP were not significantly changed from the preoperative period(all P>0.05).There was no statistically significant difference in CS,BCVA and IOP between the operated eye and the contralateral eye after surgery(all P>0.05).2 Before surgical treatment,the mean RT(t=-3.577,P=0.002)and CT(t=-2.978,P=0.007)of the macular area in the operated eye were lower than those in the contralateral eye,and the differences were statistically significant;while the GCC and RNFL were not statistically significant compared with the contralateral eye(all P>0.05).After surgical treatment,RT(t=-2.173,P=0.041)and CT(t=-2.759,P=0.012)were significantly increased in the operated eye compared with the preoperative one,and the difference was statistically significant;GCC and RNFL were not statistically significant compared with the preoperative one(all P>0.05).After surgical treatment,there were no significant changes in RT,CT,GCC and RNFL in the contralateral eye compared with the preoperative one(all P>0.05).The differences in RT,CT,GCC and RNFL between the operated and contralateral eyes after surgery were not statistically significant(all P>0.05).3 Before surgical treatment,the vascular density of SCP(t=-2.431,P=0.024)and CC(t=-2.769,P=0.012)in the macular area of the operated eye were significantly lower than those in the contralateral eye,and the differences were statistically significant;the vessel densities of DCP and RPC as well as the FZA area,FAZ perimeter and FAZ circularity were not statistically significant compared with the contralateral eye(all P>0.05).After surgical treatment,the SCP(t=-2.249,P=0.035)and CC(Z=-2.711,P=0.007)vessel density of the operated eye increased compared with the preoperative one,and the differences were statistically significant;the DCP,RPC,FAZ area,FAZ perimeter and FAZ circularity were not statistically significant before and after treatment(all P>0.05).After surgery,there were no significant differences in SCP,DCP,CC,RPC,FAZ area,FAZ perimeter and FAZ circularity in the contralateral eye compared with those before surgery(all P>0.05).Postoperative comparison of the SCP,DCP,CC,RPC,FAZ area,FAZ perimeter and FAZ circularity between the operated eye and the contralateral eye were not statistically significant(all P>0.05).Conclusions 1 Severe internal carotid artery stenosis alters the morphological structure of the retina and choroid to some extent,reduce blood flow to the SCP and CC.2 Surgical treatment of carotid artery stenosis can effectively improve the visual function of patients,increase the mean RT and CT thickness of the macula,and improve the perfusion of the retina and choroid in the fundus.3 OCTA can detect retinal and choroidal microstructural and blood flow changes in patients with carotid stenosis noninvasively and can be used to assess the efficacy of surgery.Figure 6;Table 9;Reference 162...