Pulsatile ocular blood flow among normal subjects and patients with high tension glaucoma

PURPOSE: To estimate pulsatile ocular blood flow (POBF) among normal subjects and to compare various parameters in eyes of primary open angle glaucoma with high intraocular pressure (IOP). METHODS: POBF was estimated in 95 eyes of 95 normal subjects above the age of 40 years and in 35 eyes of 35 primary open angle glaucoma patients using the OBF system (OBF Labs Ltd., UK). Correlation of age, gender, IOP, pulse amplitude, pulse volume and pulse rate with POBF was studied. POBF values were measured in glaucomatous patients before IOP control and one month later after control of IOP to < 22 mmHg. RESULTS: The mean POBF among normal subjects was 1382.2 +/- 413 ml/min (range 636-2291 m/min). Females had a significantly higher mean POBF (1512 +/- 347 ml/min) than males (1193 +/- 312 ml/min). The mean IOP among normal subjects was 12.6 mmHg and in glaucoma patients, 29.1 mmHg. Mean POBF in glaucomatous eyes with initially elevated IOP was 718.9 +/- 322.6 ml/min, which improved after IOP control to 1129 +/- 291 ml/min. IOP had a strong (P < .01) negative correlation with POBF (r = -0.667) CONCLUSIONS: POBF among eyes of normal subjects in this study is higher than reported among Caucasian eyes. Primary open angle glaucoma eyes with high IOP have significantly reduced ocular blood flow. Therapy aimed at lowering IOP has a positive effect onocular haemodynamics.     

Pulsatile ocular blood flow in healthy Koreans

PURPOSE: To determine the normal reference range of pulsatile ocular blood flow (POBF) values in healthy Korean subjects and to find out the factors that may affect them. METHODS: A total of 280 eyes of 280 normal subjects were included in this study. Best corrected visual acuity (BCVA), intraocular pressure (IOP), axial length, POBF, systemic blood pressure, and pulse rate were measured. The mean, standard deviation, range, and the 5th and 95th percentiles of POBF were calculated, and the influences of various parameters to POBF were determined by multiple regression analyses. RESULTS: The mean POBF value was 766.0+/-221.6 microl/min in men and 1021.1+/-249.5 microl/min in women. The 5th and 95th percentiles for POBF values were 486.0 microl/min and 1140.0 microl/min in men and 672.0 microl/min and 1458.0 microl/min in women. The POBF values were significantly influenced by gender, mean blood pressure, pulse rate, and axial length. CONCLUSIONS: Even though the POBF values were influenced by gender, BP, and axial length, we could define the normal reference range of POBF in healthy Koreans.     

不同类型音乐对健康人眼压的影响及其机制研究

目的研究听不同类型音乐对健康人眼压的影响并探讨其潜在的机制。方法横断面研究。本研究受试者为2017年10月至2018年5月中山大学在校健康学生志愿者。研究由两部分组成。在第一部分中,受试者分别听3种类型音乐(舒缓音乐、正性音乐、负性音乐)各15 min,听音乐前后测量眼压,以确定可以降低眼压的音乐,并用问卷评估受试者对每种类型音乐的情绪反应。在第二部分中,分别在7:30、9:30、11:30、13:30、15:30和17:30测量眼压,以确定每名受试者的眼压峰值时间点;在第2天,受试者在各自的眼压峰值时间听降眼压音乐15 min,分别测量听音乐前后的眼压、血压、心率,并用扫频源相干光层析成像术拍摄眼前节图像,用Image J软件测量Schlemm管横截面积和直径。采用配对t检验进行统计学分析。结果第一部分共纳入15名受试者,包括7名男性和8名女性,年龄(23±1)岁。听舒缓音乐前、后眼压分别为(12.65±2.49)、(11.62±2.51)mmHg(1 mmHg=0.133 kPa),听舒缓音乐后眼压降低,差异有统计学意义(t=-2.39,P=0.032);听正性音乐前、后眼压分别为(12.65±2.46)、(12.45±2.77)mmHg,差异无统计学意义(P=0.566);听负性音乐前、后眼压分别为(10.86±2.78)、(12.13±1.60)mmHg,听负性音乐后眼压升高,差异有统计学意义(t=2.45,P=0.029)。15人中有14人听舒缓音乐后感到放松。第二部分共纳入55名受试者,包括20名男性和35名女性,年龄(26±10)岁。在每个人的眼压峰值时间点听舒缓音乐后眼压、心率、收缩压、舒张压均降低,听音乐前、后眼压分别为(13.99±4.47)、(12.66±4.32)mmHg,心率分别为(79.57±10.43)、(75.57±9.62)次/min,收缩压分别为(118.11±13.92)、(110.82±12.67)mmHg,舒张压分别为(70.07±9.96)、(66.14±8.48)mmHg,差异均有统计学意义(t=-5.72,-3.68,-5.10,-3.65;均P<0.01)。听舒缓音乐后Schlemm管显著增大,听音乐前、后Schlemm管的横截面积分别为(230.07±92.20)、(255.96±93.36)像素,直径分别为(8.62±1.89)、(9.41±2.37)像素,差异均有统计学意义(t=2.88,3.39;均P<0.01)。结论舒缓音乐可以降低健康人的眼压,可能通过扩张Schlemm管发挥一定作用。     

Daytime variation of pulsatile ocular blood flow (POBF) in normal Chinese

Background: Pulsatile ocular blood flow (POBF) measurement is a new parameter to aid the understanding of the aetiology of low‐tension glaucoma. There has been one study reporting the diurnal variation of POBF. However, that study involved eight subjects only. This study investigated the daytime variation of POBF with a greater sample size. Methods: Twenty‐four young Chinese subjects (12 males and 12 females) were recruited. The mean age of our subjects was 23.6 years and only the right eye was analysed. All the subjects were screened for glaucoma and the POBF was measured at three‐hourly intervals from 9:00 am to 9:00 pm with an OBF tonometer (OBF Labs, UK, Ltd). The Goldmann intraocular pressure (IOP) and ‘erect arm’ systemic blood pressure (BP) were also measured. Results: The IOP was found to be higher in the daytime, reaching the highest at noon (mean of 14.29 mmHg) and gradually reduced to the lowest at 9:00 pm (mean of 12.99 mmHg). The change was marginally significant (repeated measures ANOVA, P = 0.05). The POBF demonstrated a trend to increase from 9:00 am, mean of 605.5 μl/min, to 9:00 pm, 720.1 μl/min (repeated measures ANOVA, P < 0.01). Student‐Newman‐Keuls post hoc test indicated that the difference was mainly due to the comparisons between the 9:00 am and 9:00 pm results and the 9:00 am and 6:00 pm results. The pulse amplitude did not vary significantly. The mean blood pressure also demonstrated a significant variation (repeated measures ANOVA, P < 0.01). In the analysis of covariance, no significant effects of mean blood pressure on POBF and pulse amplitude were revealed. Conclusions: The variation in POBF was due to factors other than systemic blood pressure. Practitioners should consider POBF variation in repeated measurements, for example when monitoring the medical treatment for glaucoma. Further study on POBF variation is required over a complete circadian cycle.     

The influence of sex difference in measurements with the Langham Ocular Blood Flow System

PURPOSE: To assess sex difference and parameters possibly accounting for such a difference in healthy subjects evaluated by means of the Langham Ocular Blood Flow (OBF) System.Methods: Pulse amplitude of intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) as measured with the Langham OBF System were assessed in 86 healthy men and 69 healthy women. RESULTS: Compared to men, women showed higher POBF (mean +/- SD: 722.6 +/- 152.8 versus 647.8 +/- 164.9 microL/min; P =.0056) and pulse amplitude (mean +/- SD: 2.3 +/- 0.7 versus 2.0 +/- 0.6 mm Hg; P =.0043) values. Sex difference was still significant after correcting for age, refraction, blood pressure, IOP, and pulse rate. Pulse amplitude correlated negatively with pulse rate, and POBF correlated negatively with IOP. Women had higher readings in pulse amplitude and POBF, even after correcting for age, refraction, IOP, blood pressure, and pulse rate. CONCLUSIONS: While using the Langham OBF System, one needs to be aware of sex difference that is independent of other hemodynamic parameters. How the observed difference in POBF is related to ocular blood flow, and how it might influence the preponderance of various ocular diseases in men or women remains to be clarified.     

Intraocular pressure measurement in patients with previous LASIK surgery using pressure phosphene tonometer

PURPOSE: To compare intraocular pressure (IOP) assessment in post-LASIK patients using non-contact tonometry, pressure phosphene tonometry and applanation tonometry. METHODS: Sixty-two consecutive LASIK patients were analysed preoperatively and postoperatively with non-contact, pressure phosphene and applanation tonometry. Comparisons among these values were assessed with paired sample Student t-test, Pearson's correlation test and Bland-Altman plotting. RESULTS: There was no significant difference for preoperative IOP measurement between non-contact, pressure phosphene and applanation tonometry. The mean +/-SD difference between the preoperative non-contact tonometry and postoperative pressure phosphene tonometry IOP measurements was 0.80 +/- 2.77 mmHg (P < 0.01). Postoperative applanation tonometry significantly underestimated IOP measurement by 5.45 +/- 2.96 mmHg (P < 0.001) and postoperative non-contact tonometry significantly underestimated IOP measurement by 9.96 +/- 2.25 mmHg (P < 0.001). CONCLUSION: Pressure phosphene tonometry may provide an alternative method for the assessment of IOP in post-LASIK patients.     

Pulsatile ocular blood flow in patients with low tension glaucoma.

Measurements of the intraocular pressure (IOP) pulse and pulsatile ocular blood flow (POBF) have been made in 22 patients with bilateral low tension glaucoma (LTG) and 29 healthy subjects matched as closely as possible for age, refractive error, IOP, systemic pulse pressure, and heart rate. Recordings were made in both the standing and supine positions. The amplitude of the intraocular pressure pulse was significantly lower in patients with LTG (1.2, SEM 0.1 mmHg standing, and 1.3, SEM 0.1 mmHg lying) than in healthy subjects (1.9, SEM 0.1 mmHg standing, and 2.0 SEM 0.1 mmHg lying): p less than 0.001 standing and p less than 0.002 lying. Measurement of POBF also showed a significant reduction between the healthy subjects (428 (31) SEM microliters/min standing and 345 (28) SEM microliters/min lying) and subjects with LTG (301 (27) SEM microliters/min standing and 249 (24) SEM microliters/min lying), p less than 0.005 standing and p less than 0.02 lying. This represents a difference of approximately 30% between the two groups in either posture. A close non-parametric correlation existed between the level of IOP and the POBF (r = 0.75, p less than 0.001 standing, and r = -0.55, p less than 0.02 lying). Such a correlation was not present in the healthy subjects. A reduction in POBF occurred in both groups on assuming the supine posture (healthy subjects 83 (16) SEM microliters/min, LTG subjects 52 (17) SEM microliters/min). These figures represent reductions of 19% and 17% respectively in comparison with the standing value. The results lend further confirmation to the hypothesis that vascular factors are associated with low tension glaucoma.     

Time dependent effects of sympathetic denervation on aqueous humor dynamics and choroidal blood flow in rabbits

PURPOSE: This study investigates the time-dependent effects of superior cervical ganglionectomy (SCGx) on aqueous humor dynamics and ocular blood flow in rabbits. METHODS: Measurements were made at various times between 24 hours and 12 months after SCGx. Intraocular pressure (IOP) was measured by pneumatonometry, aqueous flow by fluorophotometry and outflow facility by tonography. Uveoscleral outflow was determined by an intracameral tracer infusion technique and blood flow to the choroid was evaluated with fluorescent microspheres. Values in denervated eyes were compared with the contralateral, normally-innervated eyes using a paired Student's two-tailed t-test. RESULTS: At 24 hours after SCGx, IOP in denervated eyes was less than in normally-innervated eyes (14.6 +/- 0.8 vs 20.1 +/- 1.5 mmHg, 27%, p < 0.002). At one month, IOPs were not different between eyes. Compared with normally-innervated eyes at 10-12 months, IOP in denervated eyes was greater (20.4 +/- 0.7 vs 17.2 +/- 0.9 mmHg, 19%, p < 0.001), outflow facility was less (0.15 +/- 0.02 vs 0.21 +/- 0.01 microl/min/mmHg, 29%, p < 0.01) and blood flow to the choroid was less (12.1 +/- 5.0 vs 16.2 +/- 6.0 ml/min/gm tissue, 25%, p < 0.05). Aqueous humor flow was not significantly altered by SCGx at any time. CONCLUSIONS: The reduction in IOP at 24 hours after SCGx was not due to any change in aqueous flow or uveoscleral outflow (current study) but rather to an increase in outflow facility (previous studies). At 10-12 months, IOP was elevated because outflow facility was significantly reduced. The reduction in choroidal blood flow at 10-12 months may have occurred because of the increased IOP.     

Correlating intraocular pressure, blood pressure, and heart rate changes after jogging

PURPOSE: To examine the effects of jogging on intraocular pressure (IOP), blood pressure (BP), and heart rate (HR). METHODS: Twenty-nine healthy individuals-25 athletes and 4 untrained-were studied. IOP, systolic and diastolic BP, and HR were measured before and just after 20 minutes of jogging (submaximal--70%--aerobic exercise). RESULTS: IOP decreased after jogging. Only three individuals had unchanged IOP in one eye and one individual in both eyes. The IOP decrease (1 to 8 mmHg) was statistically significant (p<0.001). BP increased after jogging (systolic: 0 to 60 mmHg, statistically significant changes, p<0.001; diastolic: 0 to 15 mmHg, statistically significant changes, p<0.001). HR increased as well (15 to 80 pulses/min, statistically significant changes, p<0.001). However, there were individuals who presented a significant decrease of IOP and a mild BP rise and vice versa, and also individuals with mild IOP decrease and significant HR change and vice versa. The statistical analysis clearly showed that there are no linear quantitative correlations between BP or HR changes and IOP changes. CONCLUSIONS: IOP decreases after jogging. Changes in BP and HR values have no linear quantitative correlation with IOP decrease.     

Efficacy of anterior chamber paracentesis after intravitreal triamcinolone injection

PURPOSE: To investigate the efficacy of anterior chamber paracentesis for intravitreal triamcinolone acetonide injection (IVTA). METHODS: A prospective, randomized clinical trial was conducted on 30 eyes from 30 patients scheduled for IVTA (4 mg/0.1 mL). Eyes were randomly divided into two groups: eyes that had undergone anterior chamber paracentesis (Group 1, 15 eyes) and eyes that did not have anterior chamber paracentesis (Group 2, 15 eyes). Intraocular pressure (IOP) was measured by Goldmann applanation tonometry at a baseline of 2, 15, 30, and 60 minutes at 1 day and 1 week after the injection. The authors analyzed the short-term postoperative changes of the IOP in each group. RESULTS: For Group 1, the mean preoperative IOP was 15.33+/-1.72 mmHg, and the postoperative IOP at 2 and 15 minutes were 7.80+/-1.47 and 11.73+/-1.67 mmHg, respectively. For Group 2, there was a significant elevation of IOP (46.73+/-8.26 mmHg) 2 minutes after the injection, which decreased to the normal range (16.13+/-2.61 mmHg) by 15 minutes after the injection. There were no significant differences between the two groups in IOP at 15 minutes postsurgery compared with the distinct difference in IOP at 2 minutes post surgery (Student t-test, p=0.01). CONCLUSIONS: The findings suggest that routine anterior chamber paracentesis is inappropriate due to the brief immediate postoperative IOP elevation with IVTA.     

Ocular hypertensive response to topical dexamethasone ointment in children

PURPOSE: To investigate the rate and the degree of the ocular hypertensive response to dexamethasone ointment in children undergoing eyelid surgery. METHODS: Dexamethasone ointment (Dexcosil) was applied three times a day for the first week and twice a day for the second to third week postoperatively to children undergoing epiblepharon surgery. Intraocular pressure (lOP) was measured on the day before surgery, postoperative day 1, 7, 14, 21, 28 and 2 weeks thereafter until the IOP reached preoperative levels. Peak IOP, IOP net increase and time to reach a peak IOP were analyzed. Dexamethasone ointment was discontinued if the IOP was 25 mmHg or more. Results: A total of 96 children (mean age, 6.5 +/- 2.7 years) were included. Preoperative mean IOP was 13.6 +/- 2.9 mmHg (range 7-19). After dexamethasone ointment treatment, the children showed a significant rise in IOP as compared with the preoperative values. The peak IOP was 20.6 +/- 4.9 mmHg (range 11-39) and the time to reach peak IOP was 8.5 +/- 5.9 days. The low responders (delta IOP < or = 5 mmHg) of our group comprised 35.4% (34/96) of patients, intermediate responders (delta IOP 6-15 mmHg) comprised 56.3% (54/96) of patients and high responders (delta IOP > or =16) comprised 8.3% (8/96) of patients. A net increase in IOP was significantly higher in children 5 years old or less as compared with those older than 5 years (age < or =5, 9.4 +/- 7.5 mmHg vs. age > 5, 6.3 +/- 4.4 mmHg; p = 0.015, unpaired t-test). CONCLUSIONS: Ocular hypertensive response after dexamethasone ointment to the eyelids occurred frequently in children, especially those 5 years old or younger.     

The effect of axial length on ocular blood flow assessment in anisometropes

BACKGROUND: Pulsatile ocular blood flow (POBF) assessment measures the choroidal circulation and therefore provides data with diagnostic value in certain ocular diseases, such as glaucoma. The technique assumes a constant pressure-volume relationship. The current study investigated the effect of axial length on POBF from subjects with axial anisometropia. Ocular blood supply in the ophthalmic artery was also determined using colour Doppler ultrasonography. METHODS: Thirty-one normal, anisometropic subjects were recruited, whose ages ranged from 20 to 34 years. They had axial anisometropia (expressed by spherical equivalent) of at least 2 D. After Goldmann tonometry, the POBF of each eye was measured in a supine posture by one examiner, followed by a measurement of the blood flow velocity in the ophthalmic artery using colour Doppler ultrasonography in the same posture by another examiner. There was a 10 min rest between the two techniques. All the measurements were made at around the same time to eliminate any effect from diurnal variation. RESULTS: The mean anisometropia (expressed by spherical equivalent) was 3.89 +/- 1.96 D and the mean inter-ocular axial length difference was 1.49 +/- 1.00 mm. The anisometropia and axial length were significantly different between the two eyes (paired t-tests: p < 0.001). However, the intra-ocular pressure was similar between the two eyes (paired t-test: p = 0.41). The POBF was significantly lower in the eye with the longer axial length (459.3 microL min-1) than the fellow eye (590.8 microL min-1), paired t-test: p < 0.001. The pulse amplitude was also significantly lower in the eye with the longer axial length (1.61 mmHg) than the fellow eye (1.89 mmHg), paired t-test: p < 0.001. However, the blood flow velocity from colour Doppler ultrasonography did not demonstrate any significant difference between the two eyes (paired t-test: p > 0.05). CONCLUSIONS: The POBF and pulse amplitude were found to be reduced in the eye with the longer axial length but colour Doppler ultrasonography did not show any significant difference. This suggests that a new pressure-volume relation should be considered in deriving POBF. Practitioners should measure the axial length in POBF assessment.     

The effect of myopic axial elongation and posture on the pulsatile ocular blood flow in young normal subjects.

PURPOSE: This study investigated the effect of myopic axial elongation on pulsatile ocular blood flow (POBF) in young normal subjects. A regression equation was derived to quantify the effect. The effect of posture in POBF for eyes with different axial lengths was studied to determine if axial myopia, with different ocular volumes, would result in a change in POBF with various postures. METHODS: Seventy-nine normal subjects (38 males and 41 females) with different refractive errors were recruited. The mean age of the subjects was 22 years, and only the right eye was used for analysis. The axial length (AL) was measured, followed by Perkins intraocular pressure (IOP) and POBF with an OBF tonometer (OBF Labs [UK] Ltd) in a sitting posture. An "erected arm" blood pressure (BP) was measured with an automatic sphygmomanometer for the calculation of ocular perfusion pressure (OPP), using the formula: mean BP IOP, where the mean BP was calculated as one third of the systolic blood pressure plus two thirds of the diastolic blood pressure. The measurements of IOP, POBF, and BP were repeated in a supine posture. RESULTS: The POBF was negatively correlated with AL (r = -0.57, p < 0.01). The regression line was in the form of POBF (microl/min) = -78.5 x AL (mm) + 2655.7. There was a significant reduction (17%) in POBF in a supine posture (p < 0.01). The reduction was not significantly correlated with AL. The pulse amplitude also demonstrated a 10% reduction from postural variation (p < 0.01). The OPP increased significantly (33%) in the supine posture (p < 0.01). CONCLUSIONS: The POBF was significantly influenced by AL. Therefore, AL should be measured in determining the POBF, especially in young myopic subjects. The amount of postural variation in POBF was similar to previous studies with young subjects and was not affected by AL.     

A comparison of the effects of dorzolamide/timolol fixed combination versus latanoprost on intraocular pressure and pulsatile ocular blood flow in primary open-angle glaucoma patients

PURPOSE: To evaluate the effects of dorzolamide/timolol fixed combination (D/T) compared to latanoprost on intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) in primary open-angle glaucoma (POAG) patients. METHODS: Thirty patients with POAG were randomized in an open-label, cross-over study. Intraocular pressure reduction was achieved by 4 weeks medical therapy with D/T twice daily or latanoprost 0.005% dosed once in the evening. During a 4-week run-in and a 4-week wash-out period between study arms, patients ceased use of all other glaucoma medications and used timolol maleate 0.5% twice daily. Primary efficacy variables were IOP and POBF. RESULTS: There was no difference in baseline IOP and POBF parameters between the two study arms. Both D/T and latanoprost statistically significantly reduced IOP by 4.6 mmHg (p < 0.0001) and 3.75 mmHg (p < 0.0001) and increased POBF by 2.048 microl/second (p = 0.0030) and 2.147 microl/second (p = 0.0009), respectively. Repeated measures anova detected significant changes in POBF with treatment (p = 0.0361). Dorzolamide/timolol fixed combination statistically significantly increased pulse volume by 0.767 microl (p = 0.0087), while latanoprost therapy had no significant effect (p = 0.2407). CONCLUSIONS: Both drugs had similar effects in terms of IOP reduction. Dorzolamide/timolol significantly increased pulse volume while latanoprost had no effect. Further studies are necessary to establish whether the enhancement of choroidal blood flow can prevent glaucoma progression.     

The short-term effect of latanoprost on intraocular pressure and pulsatile ocular blood flow

PURPOSE: There is evidence that ocular blood flow plays a critical role in the clinical course of glaucoma. Any reduction in ocular blood flow due to topical antiglaucoma treatment should therefore be avoided. This study aimed to evaluate the short-term effect of local latanoprost application on ocular hemodynamics. METHODS: Intraocular pressure (IOP), ocular pulse amplitude (OPA), ocular pulse volume (OPV), systemic blood pressure, heart rate and the pulsatile component of ocular blood flow (POBF) were recorded using a pneumotonometer linked to the Langham Ocular Blood Flow System in 24 patients in a prospective, open-label study before and after 1 week of topical latanoprost application in both eyes. Twenty of the subjects had primary open-angle glaucoma and four had ocular hypertension. RESULTS: After 1 week of latanoprost treatment, IOP decreased significantly 6.2 +/- 2.9 mmHg in OD (P < 0.001) and 6.2 +/- 3.2 mmHg in OS (P < 0.001). Pulsatile OBF increased significantly by 201.2 +/- 167.4 microL/min in OD (P < 0.001) and 203.8 +/- 187.3 microL/min in OS (P < 0.001). Ocular pulse amplitude and OPV showed statistically significant increases (P < 0.05 and P < 0.001 respectively). Blood pressure and heart rate did not change significantly. CONCLUSION: Our results indicate that 1 week after latanoprost application, POBF, OPA and OPV were significantly increased in the eyes treated. More information on the perfusion of the optic nerve head is needed before the relevance of these findings to optic nerve head blood flow can be interpreted correctly.     

泪膜改变对Goldmann眼压测量值的影响

目的:探讨泪膜改变对Goldmann压平眼压计测量值的影响.方法:将68例(136只眼)受检者随机分为2组,每组34例.随机选择一只眼作为实验眼.另一只眼作为对照眼.A组的实验眼采用右旋糖苷70滴眼液滴眼,B组的实验眼采用粘弹剂Viscoat滴眼.采用Goldmann眼压计测量2次眼压,比较滴眼前、后测量值的差异.结果:A组对照眼第1、2次的眼压测量值分别为(14.44±2.68)mmHg(1 mmHg=0.133 KPa)、(14.47±2.69)mmHg,两次眼压测量值的差异无统计学意义(t=-0.329,P=0.744).实验眼滴右旋糖苷70滴眼液前、后的眼压测量值分别为(14.41±2.63)mmHg、(12.94±2.59)mmHg.两次眼压测量值的差异有统计学意义(t=13.949,P=0.000).B组对照眼第1、2次的眼压测量值分别为(14.29±2.96)mmHg、(14.35±3.12)mmHg,两次眼压测量值的差异无统计学意义(t=-0.466,P=0.644).实验眼滴Viscoat前、后的眼压测量值分别为(14.53±3.13)mmHg、(11.18±3.07)mmHg,两次眼压测量值的差异有统计学意义(t=22.126,P=0.000).两组的实验眼滴眼后的眼压均呈一致性的下降.结论:泪膜的改变可以使Goldmann压平眼压计的测量值产生偏差.     

Postural studies in pulsatile ocular blood flow: II. Chronic open angle glaucoma.

The pulsatile ocular blood flow (POBF) has been recorded in 15 patients with chronic open angle glaucoma. Measurements were performed during regular treatment with timolol 0.25% eyedrops, two weeks after withdrawal of this treatment, and then a further two weeks after its reinstitution. Readings were taken with subjects in both the erect and supine positions by means of a pneumotonometric probe to measure intraocular pressure (IOP), linked to a Langham ocular blood flow system. Assumption of the supine posture was associated with a significant increase in IOP in all phases of the study. Treatment with timolol lowered the mean IOP in comparison with the untreated phase (-4.4 (SEM 0.6) mmHg, p less than 0.001) but had no effect on the postural change. A significant reduction in POBF was recorded on assumption of the supine posture (-66 (SEM 18) microliters/min, p less than 0.001), representing a mean decrement of 19%. However, there were no significant differences in POBF between treated and untreated phases of the study. Comparison of the values obtained in patients with glaucoma (COAG) after withdrawal of treatment with those in subjects with ocular hypertension revealed that there was no significant difference in intraocular pressure between the two groups. However, both POBF (-68 (SEM 29) microliters/min) and the pulse amplitude of the intraocular pressure (ocular pulse: -0.45 (SEM) 0.14 mmHg) were significantly lower in the COAG patients. Pulsatile ocular blood flow is significantly lower in patients with chronic open angle glaucoma. Furthermore, the POBF and the postural response of these patients is not improved by the use of topical timolol therapy.     

Gender and age effects on pulsatile ocular blood flow

PURPOSE: To examine gender and age effects on pulsatile ocular blood flow (POBF). METHODS: Normal subjects, 152 females and 107 males, were separated into younger (40-50) and older (50-60) age groups. RESULTS: For younger women, mean POBF (15.3 +/- 3.7 microl/s) was significantly different (p < 0.01) than for older women (13.8 +/- 3.5 microl/s), younger men (13.2 +/- 3.3 microl/s), and older men (13.3 +/- 3.1 microl/s). The mean POBFs for each of the latter three groups were not significantly different (p > 0.41) from one another. The four groups showed no significant differences in intraocular pressure (p > 0.07) or refraction (p > 0.46). Pulse rate for younger women was significantly higher (p < 0.05) than for the older two groups, but there were no significant pulse rate differences (p > 0.08) between other groups. POBF was not correlated with IOP (r2 < 0.04), refraction (r2 < 0.009) or pulse rate (r2 < 0.04). CONCLUSION: Gender and age play an important role in POBF.     

Effect of changing from concomitant timolol pilocarpine to bimatoprost monotherapy on ocular blood flow and IOP in primary chronic angle closure glaucoma.

The aim of the present prospective masked study was to assess the effect of bimatoprost monotherapy on ocular blood flow and intraocular pressure (IOP) in eyes of primary chronic angle closure glaucoma patients already on concomitant timolol and pilocarpine. Thirty two patients of bilateral primary chronic angle closure glaucoma (PCACG) on topical timolol 0.5% twice a day and pilocarpine 2% three times daily were switched over to bimatoprost 0.03% once daily in both eyes. Intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) were recorded before and after starting bimatoprost and were followed up every four weeks for three months. Bimatoprost had statistically significant (p < 0.05) mean IOP reduction from 19.3 +/- 6.6 to 13.5 +/- 4.5 mmHg (30.5%) and there was improvement from 858 +/- 260 to 1261 +/- 321 microL/min (46.8%) in mean pulsatile ocular blood flow (p < 0.05). Conjunctival hyperemia (32%) was the most common adverse effect of bimatoprost. Bimatoprost 0.03% monotherapy improved ocular blood flow and provided a better diurnal IOP control than concomitant timolol-pilocarpine in eyes with primary chronic angle closure glaucoma and was found to be well tolerated.     

Differences in pulsatile ocular blood flow among three classifications of diabetic retinopathy

PURPOSE: Choroidal blood flow may be determined by pulsatile ocular blood flow (POBF) measurements. In the present study, the POBF of diabetic patients with increasingly severe retinopathy was compared with that in nondiabetic control subjects. METHODS: The study was a masked cross-sectional analysis. Seventy-seven diabetic subjects, including 13 with mild or no retinopathy, 36 with moderate to severe retinopathy, and 28 with proliferative diabetic retinopathy (PDR), previously treated with panretinal photocoagulation (PRP). Fifty-six nondiabetic control subjects served as the comparison group. All subjects underwent masked measurement of POBF in the right eye by Langham pneumotonometry. Analysis of variance (ANOVA) determined whether differences existed between groups. Pair-wise comparisons between groups were conducted by Student's t-test. RESULTS: The main outcome measures were ophthalmic pulse amplitudes, intraocular pressure (IOP), heart rate, and POBF. Patients with moderate to severe nonproliferative diabetic retinopathy (NPDR) had POBF 18% higher than the control (mean OBF, 943 microL/min). Among PRP-treated subjects with PDR, ocular blood flow was 22% below the control (mean OBF, 619 microL/min), and 34% less than moderate to severe nonproliferative diabetic retinopathy. Diabetic patients with no retinopathy or mild NPDR had OBF indistinguishable from the control (785 vs. 797 microL/min). Differences between the four groups were statistically significant by ANOVA (P < 0.0001). CONCLUSIONS: POBF is unaffected early in diabetic retinopathy, but increases significantly in eyes with moderate to severe NPDR. POBF is decreased in eyes with laser-treated PDR. These experimental data represent the largest published assessment of POBF in NPDR. This is the first study to examine POBF in subjects with PRP-treated PDR.