高眼压下视乳头形态和血流改变的顺序研究

Study on the sequence of morphological and angiographic changes due to intraocular pressure elevation in the optic nerve head

目的:探索机械压力导致的高眼压下视乳头形态学改变和视网膜血管密度改变的顺序。方法:前瞻性研究。纳入健康志愿者34例34眼。A组23例,其测试流程包括基线,两段高眼压期(15mmHg和30mmHg分别持续2min)和恢复期。B组11例,其高眼压期为眼压升高15mmHg持续10min。每阶段均采用OCT测量视乳头的布氏膜开口距离(BMO)、视乳头表面深度(ONHSD)和黄斑中心凹下脉络膜厚度(SFCT),并采用OCTA测量血管密度。结果:A组第一次眼压升高后,视乳头血管密度下降[浅层毛细血管丛,从(67.39±7.65)%降至(43.78±5.89)%,P<0.05],BMO距离、ONHSD和黄斑血管密度、SFCT均无改变。在第二次眼压升高后,视乳头及黄斑区的血管密度均下降,BMO距离、ONHSD增加(均P<0.05)。B组眼压升高后,视乳头及黄斑区的血管密度均下降,BMO距离增加,SFCT不变。视乳头的血管密度降低与BMO距离增加没有相关性(r=0.050,P>0.05)。结论:视乳头组织相对于形态学改变,更容易出现血流改变。在眼压升高过程中,视乳头和黄斑区的血流动力学改变特征不同。

AIM:To figure out the sequence of vessel density(VD)changes in the retina and deformation induced by mechanical force in the optic nerve head(ONH)tissue during intraocular pressure(IOP)elevation.METHODS:This prospective study tested 34 eyes from 34 healthy volunteers.Group A had 23 subjects.Their testing protocol included a baseline phase,two elevated IOP phases(15 mmHg and 30 mmHg respectively for 2min),and a recovery phase.Group B had 11 subjects,and their protocol included an IOP elevation of 15 mmHg for 10min.In each phase the deformation in the ONH and macular region were scanned by optical coherence tomography(OCT),and Bruch’s membrane opening(BMO)distance,the optic nerve head surface depth(ONHSD),the subfoveal choroidal thickness(SFCT)were measured,the VD was measured by OCTA.RESULTS:After the first IOP elevation in group A,the VD in the ONH decreased(superficial capillary plexuses,from 67.39±7.65%to 43.78±5.89%,P<0.05),the BMO distance,the ONHSD,the VD in the macula and the SFCT did not change.After the second IOP elevation,the VD in the ONH and in the macular region both decreased,the BMO distance and ONHSD increased(all P<0.05).After the IOP elevation in group B,the VD in the ONH and in the macular region decreased significantly,the BMO distance increased,the SFCT did not change.ONH VD reduction is not associated with BMO distance increment(r=0.050,P>0.05).CONCLUSION:The ONH tissue is more sensitive to hemodynamics than to morphological change.Hemodynamics during IOP elevation differs in the ONH and the macular tissue.