眼灌注压对人视乳头微循环的影响

目的 了解眼外负压吸引诱导的眼灌注压改变的条件下，正常人、原发性开角性青光眼(POAG)患者和正常眼压性青光眼患者(NTG)的视乳头微循环的变化，探讨视乳头局部自身调节的幅度。方法正常人8例，POAG患者10例和NTG患者7例，采用眼外负压杯吸引诱导眼压升高，负压增加的幅度为30s50mmHg，同时测量眼压。采用HRF测量视乳头处血流量。将基础状态下视乳头血流值作为基础值，当眼压升高到30mmHg和40mmHg时，分别测量这两点视乳头微循环的血流值，在40mmHg后解除负压吸引，测量负压吸引解除后1min、5min时视乳头微循环的血流值。结果 三组视乳头的基础血流量无明显差异。当眼压升高到30mmHg时，正常组的血流量仍维持稳定，但POAG组和NTG组明显下降，POAG组下降幅度超过25％，NTG组下降幅度超过45％。当眼压升高到40mmHg，正常组视乳头血流量也出现明显下降，其中0NHF下降约30％，POAG组和NTG组下降更明显，POAG组下降幅度超过50％，NTG组下降幅度超过65％。在解除负压吸引后1min，正常组血流量增加的幅度约为31％，POAG组增加约19％，NTG组无明显增加。在负压解除后5min，三组视乳头血流基本恢复到基础状态。结论 正常组视乳头微循环有一定范围的自身调节幅度，可以耐受眼灌注压一定程度的改变，POAG组和NTG组自身调节能力均有不同程度的损害。

Effect of ocular perfusion pressure on microcirculation of human optic nerve head

ObjectiveTo investigate the relationship between blood flow of the optic nerve head(ONHF) and ocular perfusion pressure in human.MethodsEight normal subjects,ten cases with primary open-angle glaucoma (POAG) and seven patients with normal tension glaucoma(NTC) from outpatient and inpatient clinic were recruited.The basic ONHFs of three groups were measured.Scleral suction was used to raise the IOP to 30 and 40 mmHg,and the ONHFs were measured with laser Doppler flowmetry.Then,the ONHFs at 1 and 5 min were measured after suction cup was removed.ResultsThe difference of basic ONHF among the normal,POAG and NTG groups was not significant.When IOP raised to 30 mmHg,the ONHF kept steady in normal group but declined over 25% in POAG group,and decreased about 45% in NTG group.When IOP raised to 40 mmHg,the ONHF in normal group decreased about 30%,and over 50% and 65% in POAG and NTG group,respectively.One minute after the suction cup was removed,the ONHF increased about 31% in normal group and about 19% in POAG group,and no significantly increased in NTG group.Five minutes after the suction cup was removed,the ONHF in three groups was recovered.ConclusionThe microcirculation of optic nerve head in the normal group is autoregulated following perfusion pressure moderately decrease,but in POAG and NTG group,the autoregulation capacity become worse.