Effect of naftidrofuryl (praxilene) on optic nerve head blood flow in the patient with glaucoma]

PURPOSE: To evaluate the effects of an S2 specific antiserotonine agent (Naftidrofuryl) on the optic nerve head blood flow in glaucomatous patient. PATIENTS AND METHOD: 11 glaucomatous subjects were enrolled in the study. After administration of 200 mg naftidrofuryl twice daily for 7 days: values of optic nerve head blood flow (Fonh), velocity and volume were recorded in the temporal rim and cup of the optic nerve head. Blood flow measurements were performed by laser doppler flow-metry at day 0 and day 7 before and one and two hours after drug administration. RESULTS: Our study showed a significant improvement of perfusion pressure (p = 0.02) at day 7 and an increase of mean ophthalmique artery pressure (p = 0.03). DISCUSSION: Our preliminary results on a small number of patients and a short follow-up indicate that the use of naftidrofuryl may enhance optic nerve head blood flow in glaucomatous patients. Further studies may confirm these results.     

Blood flow per unit retinal nerve fibre tissue volume is lower in the human inferior retina

AIM: To determine if perfusion per unit tissue volume of retinal nerve fibre layer and optic nerve head in the inferior sector is lower than in the superior sector. METHODS: Heidelberg retinal tomogram (HRT) for topographic measurement of optic nerve head and retinal nerve fibre layer and Heidelberg retinal flowmeter (HRF) for retinal blood flow were performed on 19 normal healthy subjects. Measurements from the superior and inferior sectors were compared. The perfusion/nerve fibre ratio (PNR); the blood flow per unit retinal nerve fibre tissue volume, was calculated in each sector with a formula; HRF flow measurements divided by HRT measurements. RESULTS: Retinal nerve fibre layer thickness in the inferior retina was significantly higher than in the superior retina (p<0.05). There were, however, no differences in retinal blood flow between the superior and inferior retinal sectors. The PNR in the inferior sector were significantly lower than in the superior sector (p=0.047 for HRF mean flow/rim volume and p = 0.0282 for HRF 75th percentile flow/rim volume). CONCLUSIONS: The inferior sector of retinal nerve fibre layer and optic nerve head may have lower blood flow per unit nerve tissue volume compared to the superior sector. This result suggests that the inferior sector is more vulnerable to elevated intraocular pressure (IOP) and ischaemic insults in glaucomatous optic neuropathy.     

Use of magnetic resonance imaging to differentiate optic neuritis and nonarteritic anterior ischemic optic neuropathy

OBJECTIVE: To determine if magnetic resonance imaging (MRI) of the optic nerves obtained during the acute phase can distinguish patients with optic neuritis (ON) from those with nonarteritic anterior ischemic optic neuropathy (NAION). DESIGN: Retrospective, neuroradiologic, observational study. PARTICIPANTS: Sixty-four patients diagnosed as having either ON or NAION who were diagnosed by clinical criteria and imaged by MRI. METHODS: Demographic information on the MRI scans was masked and the patients were presented randomly and in a blinded fashion to a neuroradiologist (JDR) for determination of abnormalities. Reproducibility was assessed by presenting 10 of the scans a second time to the same neuroradiologist. MAIN OUTCOME MEASURES: The presence or absence and location of abnormal MRI signals of the optic nerve. RESULTS: Evaluation of reproducibility revealed identical interpretations of the ten scans submitted a second time. The optic nerve was abnormal in the clinically affected eye in 31 of the 32 ON patients but in only 5 of the 32 NAION patients. Thirty of the 31 ON patients who received gadolinium had enhancement, and 27 of the 32 ON patients had increased short T(1) inversion recovery signal in the clinically affected optic nerve. The five NAION patients with abnormal scans in the clinically affected eye had increased short T(1) inversion recovery signal, and in two of these, there also was enhancement of the optic nerve. For the ON patients, enhancement involved the entire length of the intraorbital optic nerve in 18 cases and the intracranial segment of the optic nerve in 19 cases. CONCLUSIONS: Our study shows that MRI scanning of the optic nerve shows significantly different results between patients clinically diagnosed with either ON or NAION.     

Glaucoma progression is associated with decreased blood flow velocities in the short posterior ciliary artery

BACKGROUND: An altered perfusion of the optic nerve head has been proposed as a pathogenic factor in glaucoma. AIM: To investigate potential differences in the ocular haemodynamics of patients having glaucoma with progressive versus stable disease, as well as healthy volunteers. METHODS: Peak-systolic velocity (PSV), end-diastolic velocity (EDV) and resistivity index in the short posterior ciliary artery (SPCA), central retinal artery (CRA) and ophthalmic artery were recorded in 114 consecutive patients having glaucoma with an intraocular pressure (IOP) < or =21 mm Hg, as well as in 40 healthy volunteers, by colour Doppler imaging (CDI). RESULTS: Of the 114 patients with glaucoma, 12 showed glaucoma progression (follow-up period: mean 295 (standard deviation (SD) (18) days). CDI measurements in these patients showed decreased PSV and EDV in the SPCA (p<0.001 and p<0.05, respectively) and decreased PSV in the CRA compared with patients with stable glaucoma and healthy controls (p<0.05). No differences in flow velocities were found for the ophthalmic artery. IOP and systemic blood pressure was similar in all the three groups. CONCLUSIONS: Progressive glaucoma is associated with decreased blood flow velocities in the small retrobulbar vessels supplying the optic nerve head. The detected difference could represent a risk factor for progression of glaucomatous optic neuropathy.     

The vascular pattern of the optic nerve and its potential relevance in glaucoma

Evidence that vascular factors contribute to the pathogenesis and development of glaucomatous optic neuropathy continues to accumulate. A higher than expected prevalence of systemic vascular disorders in individuals with glaucoma has been documented. New sophisticated in vivo analysis techniques, such as ultrasound color Doppler imaging, suggest that decreased blood flow velocity and increased vascular resistance are present in the vessels serving the optic nerve of human subjects with glaucoma, implying the presence of either organic or functional vascular disorders in these individuals. Recognizing that different analysis techniques have led to conflicting observations, experimental models have been developed to provide an additional tool with which to interpret the effects of compromised optic nerve perfusion.     

Effect of dorzolamide and timolol on ocular blood flow in patients with primary open angle glaucoma and ocular hypertension

BACKGROUND: There is evidence that perfusion abnormalities of the optic nerve head are involved in the pathogenesis of glaucoma. There is therefore considerable interest in the effects of topical antiglaucoma drugs on ocular blood flow. A study was undertaken to compare the ocular haemodynamic effects of dorzolamide and timolol in patients with primary open angle glaucoma (POAG) or ocular hypertension (OHT). METHODS: One hundred and forty patients with POAG or OHT were included in a controlled, randomised, double blind study in two parallel groups; 70 were randomised to receive timolol and 70 to receive dorzolamide for a period of 6 months. Subjects whose intraocular pressure (IOP) did not respond to either of the two drugs were switched to the alternative treatment after 2 weeks. Scanning laser Doppler flowmetry was used to measure blood flow in the temporal neuroretinal rim and the cup of the optic nerve head. Pulsatile choroidal blood flow was assessed using laser interferometric measurement of fundus pulsation amplitude. RESULTS: Five patients did not respond to timolol and were changed to the dorzolamide group, and 18 patients changed from dorzolamide treatment to timolol. The effects of both drugs on IOP and ocular perfusion pressure were comparable. Dorzolamide, but not timolol, increased blood flow in the temporal neuroretinal rim (8.5 (1.6)%, p<0.001 versus timolol) and the cup of the optic nerve head (13.5 (2.5)%, p<0.001 versus timolol), and fundus pulsation amplitude (8.9 (1.3)%, p<0.001 versus timolol). CONCLUSIONS: This study indicates augmented blood flow in the optic nerve head and choroid after 6 months of treatment with dorzolamide, but not with timolol. It remains to be established whether this effect can help to reduce visual field loss in patients with glaucoma.     

Optic nerve oxygenation

The oxygen tension of the optic nerve is regulated by the intraocular pressure and systemic blood pressure, the resistance in the blood vessels and oxygen consumption of the tissue. The oxygen tension is autoregulated and moderate changes in intraocular pressure or blood pressure do not affect the optic nerve oxygen tension. If the intraocular pressure is increased above 40 mmHg or the ocular perfusion pressure decreased below 50 mmHg the autoregulation is overwhelmed and the optic nerve becomes hypoxic. A disturbance in oxidative metabolism in the cytochromes of the optic nerve can be seen at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human glaucoma patients is six times higher at a perfusion pressure of 30 mmHg, which corresponds to a level where the optic nerve is hypoxic in experimental animals, as compared to perfusion pressure levels above 50 mmHg where the optic nerve is normoxic. Medical intervention can affect optic nerve oxygen tension. Lowering the intraocular pressure tends to increase the optic nerve oxygen tension, even though this effect may be masked by the autoregulation when the optic nerve oxygen tension and perfusion pressure is in the normal range. Carbonic anhydrase inhibitors increase the optic nerve oxygen tension through a mechanism of vasodilatation and lowering of the intraocular pressure. Carbonic anhydrase inhibition reduces the removal of CO2 from the tissue and the CO2 accumulation induces vasodilatation resulting in increased blood flow and improved oxygen supply. This effect is inhibited by the cyclo-oxygenase inhibitor, indomethacin, which indicates that prostaglandin metabolism plays a role. Laboratory studies suggest that carbonic anhydrase inhibitors might be useful for medical treatment of optic nerve and retinal ischemia, potentially in diseases such as glaucoma and diabetic retinopathy. However, clinical trials and needed to test this hypotheses.     

Anterior optic nerve capillary blood flow response to diurnal variation of mean ocular perfusion pressure in early untreated primary open-angle glaucoma

PURPOSE: To examine the impact of diurnal variation in intraocular pressure (IOP) and mean ocular perfusion pressure (MOPP) on the variation in anterior optic nerve capillary blood flow (BF) in patients with untreated early primary open-angle glaucoma (uPOAG) and healthy volunteers. METHODS: Fourteen patients with uPOAG (age, 56.3 +/- 12 years [SD]; seven men) and 14 normal subjects (age, 57.6 +/- 9.9 years; five men) were examined. Diurnal IOP, systolic (SBP) and diastolic (DBP) blood pressures, and optic nerve head (ONH) topography were measured every hour; and diurnal BF was measured by flowmeter every 2 hours between 0700 and 2200 hours. A perfusion image analyzer was used to calculate the mean BF within the rim (mean rim flow, MRF). The local flow (LF) was calculated using the median and mean flow rates within a 10 x 10-pixel window placed on the rim in the area of maximum topography fluctuation (MTF). The MOPP was then calculated. Mixed-effect linear models were used to analyze the repeated measures data in which both fixed and random effects were included. RESULTS: IOP, BP, and MOPP had significant diurnal variation (P < 0.040). LF measured at the sector of MTF significantly changed in patients with uPOAG (P = 0.006) but not in normal subjects (P = 0.660). MRF did not show significant diurnal change in either group (P = 0.130, P = 0.770). LF increased significantly after lunch in the uPOAG group (P = 0.001). SBP had a significant effect on LF over the course of the day in the uPOAG group (P = 0.043). The diurnal change in IOP, BP, and MOPP did not have a significant effect on MTF in either group. In uPOAG, the local flow, in areas of greatest topographical change, correlated inversely with IOP at 0700 hours (P < or = 0.002). CONCLUSIONS: The mean rim flow did not change during the day, implying that the anterior optic nerve capillary blood flow was autoregulated in both normal subjects and in patients with uPOAG, despite significant changes in IOP and MOPP. However, the regions of greatest diurnal change in rim topography (MTF) had significant diurnal change in capillary blood flow in patients with uPOAG but not in normal subjects.     

Effect of topical dorzolamide on optic nerve head blood flow

· Purpose: The topical carbonic anhydrase inhibitor dorzolamide has proven effective in lowering intraocular pressure in glaucoma patients. Because an impaired blood supply of the optic nerve has to be regarded as a major pathogenic risk factor it seems important to examine the effect of this new antiglaucomatous drug on capillary optic nerve head blood flow. · Methods: In a double-masked, randomized clinical trial, dorzolamide eye drops were applied to both eyes of 15 healthy subjects (8 female, 7 male, mean age 30.6 years) three times daily for 3 days. The control group (15 healthy volunteers, 9 female, 6 male, mean age 30.8 years) received a placebo preparation according to the same protocol. Intraocular pressure (IOP), blood pressure, heart rate, capillary optic nerve head blood flow and retinal blood flow were measured at baseline (1D0), 90 min after single instillation (1D90), and after 3 days of therapy (3D). Scanning laser Doppler flowmetry (Heidelberg Retina Flowmeter) and laser Doppler flowmetry according to Riva (Oculix 4000) were used to measure optic nerve head blood flow. · Results: IOP dropped in dorzolamide-treated subjects from 12.5 mmHg to 11.0/10.5 mmHg (1D0, 1D90, 3DO) and in the control group from 13.0 mmHg to 12.5/12.5 mmHg. Optic nerve blood flow as measured by scanning laser Doppler flowmetry showed no significant changes in dorzolamide-treated volunteers (temporal 310/329/315 AU, nasal 387/402/399 AU) or in the placebo group (temporal 238/306/276 AU, nasal 356/382/379 AU). Also as measured by laser Doppler flowmetry optic nerve head blood flow did not show significant changes in dorzolamide-treated volunteers (temporal 12.98/12.6/11.7 AU, nasal 16.6/16.9/15.7 AU) or in the placebo group (temporal 11.9/12.4/12.4 AU, nasal 16.1/15.8/17.7 AU). The systemic parameters blood pressure and heart rate remained unchanged during the treatment period. · Conclusion: The results showed the expected drop in IOP. However, capillary optic nerve head blood flow, measured by two different techniques, did not change during therapy. This may be due to the effective autoregulation in human optic nerve head circulation, which seems not to be affected by dorzolamide. Received: 16 February 1998 Revised version received: 9 September 1998 Accepted: 12 October 1998     

Effect of timolol on anterior optic nerve blood flow in patients with primary open-angle glaucoma as assessed by the Heidelberg retina flowmeter

PURPOSE: To evaluate the effect of 0.5% timolol maleate on the capillary circulation of the anterior optic nerve head in patients with primary open-angle glaucoma and to compare the results with those obtained in a healthy control group. PATIENTS AND METHODS: Twelve patients with nonprogressive glaucoma and 12 age- and sex-matched healthy volunteers were included in this prospective study. Optic nerve head perfusion was examined by the Heidelberg Retina Flowmeter (HRF) in both groups. A 3-week washout period preceded the baseline measurement in the glaucoma group, and ONH blood flow was assessed again after 3 weeks of bilateral topical timolol treatment and 2 hours after timolol application. RESULTS: Intraocular pressure decreased significantly with timolol (P < 0.001). The HRF flow values for patients with glaucoma were comparable to those for a control group at baseline (P = 0.25), 3 weeks after timolol therapy (P = 0.09), and 2 hours after timolol instillation (P = 0.15). The glaucoma group showed no statistically significant change in the HRF parameter flow as compared with baseline, either after 3 weeks of timolol treatment or 2 hours after timolol instillation (P = 0.40). The heart rate and arterial systolic and diastolic blood pressure values showed no alteration after timolol therapy. CONCLUSIONS: Patients with nonprogressive glaucoma seem not to have an altered optic nerve blood flow as assessed by the HRF, and timolol treatment does not seem to alter the latter blood flow parameter in such patients.     

Effects of dopamine on retinal and choroidal blood flow parameters in humans

AIM: To investigate the effect of dopamine on retinal and choroidal blood flow in humans. METHODS: We investigated the effect of two doses of intravenous dopamine (5 and 10 microg/kg/min) via a randomised double-masked crossover study in 12 healthy subjects chosen from a total of 16. Blood flow parameters in retina, optic nerve head and choroid were assessed with bi-directional laser Doppler velocimetry, laser Doppler flowmetry and laser interferometric measurement of fundus pulsation amplitude, respectively. RESULTS: Intravenous dopamine dose-dependently increased retinal blood cell velocity and fundus pulsation amplitude (p<0.001). At the highest administered dose red blood cell velocity in retinal vessels increased by 37% and fundus pulsation amplitude by 24%. By contrast, optic nerve head blood flow did not change with dopamine administration. CONCLUSIONS: Our data indicate that dopamine has a pronounced enhancing effect on the retinal perfusion in humans. Further studies are required to establish the exact role of dopamine in the regulation of choroidal and optic nerve head blood flow.     

Perfusion of the optic nerve head and visual field damage in glaucomatous patients

PURPOSE: To examine the relation between perfusion of the optic nerve head and visual field defects in glaucomatous patients. METHODS: A study was performed on 94 patients affected with primary open-angle glaucoma. The optic nerve head blood flow was measured by means of a scanning laser Doppler flowmeter (Heidelberg Retina Flowmeter). Blood volume, flow and velocity were analysed in two areas of the rim and in one area of the lamina cribrosa. The visual field was tested with the 30-2 full threshold white-on-white program and mean deviation (MD) and corrected pattern standard deviation (CPSD) were considered as parameters of visual field defects. RESULTS: The interindividual analysis showed that the vascular parameters of the neuroretinal rim circulation were not significantly correlated with visual field parameters. The blood volume, flow and velocity of lamina cribrosa correlated significantly with both MD (R=0.519, R=0.549 and R=0.531, respectively; P<0.001) and CPSD (R=-0.496, R=-0.363 and R=-0.363, respectively; P<0.001). The intraindividual correlations (right-left differences of parameters) showed that the side differences of MD and CPSD correlated significantly with the side differences of blood volume (R=0.511 and R=-0.477, respectively), flow (R=0.554 and R=-0.390, respectively) and velocity (R=0.541 and R=-0.372, respectively) in lamina cribrosa. CONCLUSION: These findings suggest that in glaucoma patients the perfusion parameters of lamina cribrosa are significantly correlated with visual field defects.     

Ocular blood flow and systemic blood pressure in patients with primary open-angle glaucoma and ocular hypertension

PURPOSE: There is evidence that altered optic nerve head (ONH) blood flow may play a role in the development and progression of glaucoma. In the present study, the baseline characteristics were examined in a study population participating in a clinical trial in which the ocular hemodynamic effects of timolol and dorzolamide were compared. METHODS: One hundred forty patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT) were included in this trial and their baseline parameters compared with those of a group of 102 age-matched control subjects. Scanning laser Doppler flowmetry was used to measure blood flow in the temporal neuroretinal rim and the cup of the ONH. Pulsatile choroidal blood flow was assessed by laser interferometric measurement of fundus pulsation amplitude. In addition, hemodynamic parameters and mean arterial pressure were calculated in both groups. RESULTS: All ocular hemodynamic parameters were significantly lower in the POAG/OHT group compared with the healthy control group (P < 0.001 each). In addition, a significant positive correlation between laser Doppler flowmetry readings and mean arterial pressure was observed in patients with glaucoma but not in healthy control subjects. Likewise, the correlation coefficient between fundus pulsation amplitude and mean arterial pressure was higher in patients with glaucoma than in healthy control subjects. CONCLUSIONS: The present study indicates reduced ONH and choroidal blood flow and an abnormal association between blood pressure and ocular perfusion in patients with primary open-angle glaucoma or ocular hypertension, independent of topical antiglaucoma medication. Hence, vascular dysregulation appears to be an early manifestation in glaucoma that is not caused by pharmacologic intervention.     

Color Doppler image of central retinal artery of eyes with an intraconal mass

PURPOSE: Retinal ischemia secondary to hypoperfusion of the central retinal artery is recognized as one factor that may contribute to the development of loss of vision in eyes with intraorbital tumors. We study intraorbital tumors which produce motility disturbances and visual problems by color Doppler imaging to evaluate this factor. METHODS: We examined the central retinal artery velocities of 3 patients with disc edema caused by intraconal masses (2 cavernous hemangiomas and 1 presumed optic nerve glioma) via color Doppler imaging. RESULTS: The time-velocity waveform demonstrated abnormally high vascular resistance in the central retinal artery of all affected eyes in the primary position compared with the normal waveform seen in the other eyes. We compared the pulsatility index of eyes with an intraconal mass and contralateral, control eyes using Student's t test for paired samples and significant differences were noted between both groups (p< 0.01). CONCLUSIONS: Intraconal tumors could produce increased pressure in the optic nerve sheath and the optic nerve tissue which could be associated with impaired retinal and optic nerve blood flow and the subsequent amaurosis encountered with intraorbital tumors.     

Evaluation of optic nerve head and peripapillary retinal blood flow in glaucoma patients, ocular hypertensives, and normal subjects

PURPOSE: To compare optic nerve head (ONH) and peripapillary retinal blood flow in subjects with open-angle glaucoma (OAG), ocular hypertension (OHT), and normal eyes (NOR) using full-field perfusion analysis of scanning laser Doppler flowmetry (SLDF) images. DESIGN: Prospective, nonrandomized clinical trial. METHODS: Twenty uncontrolled OAG patients, 20 uncontrolled OHT patients, and 20 normal volunteers were prospectively enrolled. Mean ONH and peripapillary retinal blood flow measurements were performed by SLDF version 3.3 using five Heidelberg Retina Flowmeter (Heidelberg Engineering, Heidelberg, Germany) images. Statistical evaluations were performed on the three study groups using one-way analysis of variance. Flow values of the neuroretinal rim of the ONH, nasal peripapillary retina, and temporal peripapillary retina were then correlated with the clinical parameters of age, cup/disk (C/D) ratio, intraocular pressure (IOP), visual field mean defect, maximum-recorded IOP, and ocular perfusion pressure.Neuroretinal rim blood flow in the OAG group was 158 +/- 79 arbitrary units (au), whereas in the OHT group it was 277 +/- 158 au, and in the NOR group it was 272 +/- 93 au. Differences were statistically significant between the OAG group and each of the other groups (P =.001) but not between OHT and NOR groups (P =.91). Peripapillary retinal flow values showed no statistically significant differences between groups (P =.76 nasal and 0.93 temporal). RESULTS: Neuroretinal rim flow values showed a significant inverse correlation with C/D ratio (P =.001). Mean neuroretinal rim blood flow was significantly higher (350 +/- 184 au) in the 10 OHT patients with C/D ratios < 0.4 when compared with the 10 OHT patients with larger C/D ratios (203 +/- 79 au) (P =.039). Conversely, peripapillary retinal blood flow showed no significant correlation with any clinical parameter. CONCLUSION: Open-angle glaucoma patients had significantly lower blood flow in the ONH compared with OHT patients and normal volunteers. No significant differences in ONH blood flow were found between ocular hypertensives and normal volunteers. For peripapillary retinal blood flow, no significant difference was seen between any groups. Neuroretinal rim blood flow was significantly inversely correlated to increased C/D ratio. Ocular hypertensives with larger C/D ratios demonstrated significantly lower rim blood flow compared with those with smaller C/D ratios, suggesting that rim perfusion might be reduced in high-risk ocular hypertensives before the manifestation of visual field defects.     

24小时血压参数与原发性开角型青光眼视神经损害的相关性

目的：研究24 h血压参数与原发性开角型青光眼（POAG）视神经损害之间的相关性。方法：病例对照研究。选择2013年6月至2016年12月期间成都市第一人民医院确诊的60例POAG患者作为POAG组,55 例正常人群作为对照组。2 组均进行24 h眼压和血压的同步监测,比较2 组受检者24 h血压参数、眼灌注压及眼压的差异,并分析POAG组患者24 h血压参数、眼灌注压及眼压与相关视功能之间的关系。采用独立样本t检验和多重线性回归等进行统计学分析。结果：①POAG组的24 h平均眼压、眼压差、眼灌注压差及脉压差显著高于对照组,2 组差异均有统计学意义（t =3.22、6.57、2.29、2.39,P ＜0.05）。②POAG组平均收缩压显著高于对照组（t =3.02,P =0.003）,其收缩压最高值、收缩压波动值、夜间平均收缩压、夜间最高收缩压及其波动值均显著高于对照组（t =4.38、5.27、4.13、4.13、 4.14,P ＜0.001）。③POAG组24 h平均舒张压、舒张压最高值、夜间平均舒张压、夜间舒张压最高值也显著高于对照组（t =2.22、2.50、2.29、2.10,P ＜0.05）。④POAG组患者的24 h血压相关参数与视神经损害相关性：平均眼压是POAG视野的平均缺损值（MD）的影响因素,二者呈负相关（b =-0.44,P =0.004）;盘周平均视网膜神经纤维层（RNFL）厚度与平均眼压（b =-0.956,P =0.001）、眼压差（b =-1.125,P =0.003）呈负相关;夜间平均舒张压（b =0.395,P ＜0.001）和夜间平均动脉压（b =0.046,P =0.001）分别与AP100和AP50值呈正相关。结论：①24 h血压相关参数与POAG的视神经损害之间存在相关性;②夜间眼灌注压、夜间舒张压和夜间动脉压可能是POAG视神经损害的影响因素;③在POAG的治疗中,稳定的血压和靶眼压有利于保持有效的稳定的眼灌注压,提示在关注降眼压治疗POAG的同时应该关注血压的变化。     

Retinal blood flow measurements and neuroretinal rim damage in glaucoma

AIM: To assess retinal blood flow characteristics in subjects with normal tension glaucoma (NTG), primary open angle glaucoma (POAG), and a group of controls using the Heidelberg retina flowmeter (HRF). The vascular parameters were correlated against structural damage of the optic nerve head, assessed using the Heidelberg retina tomograph (HRT). METHODS: HRF images were obtained in 76 subjects with NTG, 58 with POAG, and 38 controls. Optic nerve head images, acquired using the HRT, were analysed with Moorfields Regression Analysis software. The HRF variables, measured adjacent to a rim segment identified as "abnormal," were compared with the vascular parameters of the "normal" rim segments. The HRF parameters of the segments identified as normal in glaucoma subjects were compared with matched control segments. RESULTS: The glaucoma subjects had significantly lower retinal haemodynamics than the control subjects. There were no significant differences in the HRF parameters between the NTG and POAG subjects. The discs that had been identified as having abnormal segments had lower HRF values than those with a corresponding normal segment. The glaucoma subjects with normal rim segments had statistically significant lower velocity, flow, and volume measurements than the controls for each location sampled. CONCLUSION: This study shows a relation between structural damage of the optic nerve head and the level of retinal blood flow. The changes in the circulation could indicate that it may be an early marker of the pathological process.     

Early Orbital Blood Flow Changes in Multiple Sclerosis Patients with Unilateral Acute Optic Neuritis

The aim of this study was to evaluate orbital blood flow by using colour Doppler imaging before corticosteroid administration in multiple sclerosis patients with unilateral acute optic neuritis. Thirty multiple sclerosis patients with unilateral acute optic neuritis and 30 healthy subjects were included as the study and the control groups. The diagnosis of multiple sclerosis optic neuritis was based on clinical presentation, visually evoked potential, and magnetic resonance imaging findings. Data obtained from affected and unaffected eyes were compared with each other and the control group. Ophthalmic artery peak systolic velocity, end-diastolic velocity, resistivity index, and pulsatile index were measured in all patients before administration of systemic corticosteroid treatment and in control subjects. All parameters of blood flow obtained from affected eyes of patients who developed acute optic neuritis were significantly higher than those of the clinically uninvolved eyes of the affected patients (p < 0.001) and those of control eyes (p < 0.001). In addition, statistically significant increases were found in ophthalmic artery peak systolic velocity, end-diastolic velocity, and resistivity index of the clinically uninvolved eye of the affected patients compared with the control group (p = 0.002, p = 0.012, p = 0.013, respectively). No significant differences were found in blood flow data between left and right eyes of the control group (p > 0.05).     

The effect of age on optic nerve head blood flow

PURPOSE: To examine whether optic nerve head blood flow changes with aging. METHODS: One randomly chosen eye of each of 103 healthy subjects (age range, 22-76 years) was examined by laser Doppler flowmetry. Relative capillary blood flow, velocity, and volume of the moving red blood cells were measured at the temporal and nasal neuroretinal rim of the optic nerve head. For statistical analysis, linear regression analysis and partial correlations were calculated. RESULTS: Velocity increased with age. The Pearson correlation coefficient (R) between age and velocity was 0.49 temporally and 0.56 nasally. The correlation was significantly different from 0 (both P < 0.0005). Volume decreased with increasing age. The Pearson correlation coefficient between age and volume was -0.47 temporally and -0.40 nasally. The correlation was significantly different from 0 (both P < 0.0005). Flow decreased with increasing age. The Pearson correlation coefficient between age and flow was -0.27 temporally and -0.31 nasally. The correlations were significantly different from 0 (P = 0.006 and P = 0.002, respectively). Partial correlation coefficients between the perfusion parameters and age, after correcting for systolic and diastolic blood pressure, heart rate, gender, and IOP, were similar compared to the Pearson correlation coefficients and remained statistically significant. CONCLUSIONS: The perfusion of the optic nerve head is altered with increasing age. The results suggest that the blood supply is reduced in elderly subjects.     

Verhältnis zwischen retrobulbären Blutflussgeschwindigkeiten und glaukomatösem Schaden Ein intraindividueller Vergleich

BACKGROUND: Glaucomatous optic nerve damage is thought to be influenced by ocular perfusion. The aim was to investigate if a difference in visual field and Heidelberg retinal tomography (HRT) between two eyes of an individual glaucoma patient is reflected in different blood flow velocities in retrobulbar vessels. METHODS: Data from 53 patients including 26 normal tension glaucoma patients (NTG) and 27 high tension glaucoma patients (HTG) were evaluated retrospectively. In 38 patients asymmetric glaucomatous damage (AGD) could be demonstrated by both structural (HRT) and functional measures (static or Goldmann perimetry). In 15 patients there was symmetric glaucomatous damage (SGD). To discriminate between AGD and SGD we used a score for HRT and visual field. Color Doppler imaging (CDI) was performed with a Siemens Quantum 2000. RESULTS: No significant differences were found when comparing group means of intraindividual deviation of CDI in patients with AGD vs. SGD. Overall analysis of CDI values in NTG vs. HTG eyes also showed no significant differences. Nevertheless we measured decreased blood flow velocities for NTG compared to HTG eyes especially in short posterior ciliary arteries, peak systolic and end diastolic velocities. CONCLUSIONS: A simple correlation between retrobulbar blood flow velocities and glaucomatous damage could not be found. However, color Doppler images can give important additional information in the diagnosis of glaucoma, especially normal tension glaucoma.