Measurement of the retinal venous pressure with a new instrument in patients with primary open angle glaucoma

PURPOSE

To compare the results of retinal venous pressure (RVP) measurement performed with contact lens dynamometry (CLD) and with the new IOPstim.

METHODS

In this cross-sectional study, we included 36 patients with primary open angle glaucoma with a median age (Q25; Q75) of 74 (64; 77) years (m/f = 18/18), baseline intraocular pressure (IOP): 13.9 (12.2; 15.1) mmHg. Median mean defect: - 5.8 (- 11.9; - 2.6) db. Principle of the IOPstim: an empty balloon with a diameter of 8 mm is positioned on the eye, laterally of the limbus. Under observation of the central retinal vein (CRV), the examiner inflates the balloon. As soon as the CRV starts pulsation, the inflation is stopped and the IOP is measured, equaling the RVP at this moment. In the CLD, the pulsation of the CRV is observed with a contact lens. The RVP is calculated from the attachment force applied when pulsation appears.

COURSE OF EXAMINATIONS

Three single measurements of RVP in quick succession with both methods. The sequence of the two methods was randomized. The means of the three RVP measurements were compared.

RESULTS

Pressures in mmHg. RVP: IOPstim: 19.4 ± 5.4 (mean ± SD), CLD: 20.3 ± 5.9. Range of three single measurements: IOPstim: 2.9 ± 1.5, CLD: 2.2 ± 1.1. The differences were RVPIOPstim - RVPCLD =  - 0.94 ± 1.15, and approximately normally distributed. Bland-Altman analysis: only one data point was 0.5 mmHg higher than the upper line of agreement. The confidence interval of this line was 0.65 mmHg. Concordance correlation coefficient according to Lin (CCC): 0.96. Intraclass correlation coefficient: both methods, 0.94.

CONCLUSION

In both methods, the range of the single measurements may be taken as a sign of good reliability, the CCC of 0.96 as a sign of a very good agreement. At the mean, the IOPstim RVP values were 1 mmHg lower than those obtained with the CLD. This difference may be due to the different directions of the prevailing force vectors induced by the instruments. The IOPstim seems applicable in glaucoma diagnostics.

Ocular circulation change in optic disc melanocytoma - a case report and a review of the literature

BACKGROUND

Ocular circulation in optic disc melanocytoma (ODM) has not yet been well evaluated. We quantitatively evaluated longitudinal changes in the morphology and circulation hemodynamics of the disc and macula using optical coherence tomography angiography (OCTA) and laser speckle flowgraphy (LSFG) in a patient with optic disc melanocytoma.

CASE PRESENTATION

A 50-year-old woman was referred to our hospital due to a dark pigmented tumor over the superior optic disc area of the left eye noted on physical examination. At the first visit, the patient's best-corrected visual acuity (BCVA) was 20/20 in both eyes, and the intraocular pressure (IOP) was 17 and 18 mmHg in the left and right eyes, respectively. Fluorescein angiography (FA) showed blockage of fluorescence in the topography of the lesion, and indocyanine green angiography (ICGA) showed hypofluorescence at all times. On LSFG, a low mean blur rate (MBR) was noted in the optic disc all area (MBRa) and tissue (MBRt) compared to the contralateral eye at the first visit and at the 3-month follow-up. A relatively low MBR was also detected in the macular area of the affected eye and the tumor itself. OCTA detected blood vessel networks in the deep retinal layer of the tumor. The visual field showed no specific defects. During follow-up, there was no tumor enlargement or vision decrease.

CONCLUSIONS

We found that a lower MBR of the disc and macula area was noted on LSFG in this patient with optic disc melanocytoma, and it was continually observed at the 3-month follow-up. Although blood vessel networks in the deep retinal layer of the tumor were detected by OCTA, vascular compromise in the surrounding disc area and macula was found. Therefore, these results further increase our knowledge about the role that circulation impairment plays in the pathogenesis of the disease while vision is unaffected.

The relationships between the pulsatile flow form of ocular microcirculation by laser speckle flowgraphy and the left ventricular end-diastolic pressure and mass

To evaluate the relationships between parameters of the pulsatile flow form in the optic nerve head shown by laser speckle flowgraphy (LSFG) and the left ventricular (LV) end-diastolic pressure and mass obtained by echocardiography. We cross sectional analyzed the cases of 175 subjects who had undergone polysomnography. Standard M-mode two-dimensional color Doppler imaging was performed to evaluate the E/e' ratio (which represents the LV end-diastolic pressure) and LV mass. The pulsatile flow form analysis parameters of the blowout score and acceleration time index were evaluated. The parameters were analyzed separately for the tissue, vessels and throughout the optic nerve head (All). We performed a single regression analysis and a multiple regression analysis to determine whether pulsatile flow form are independent factors for the E/e' ratio and LV mass. The factors contributing independently to the E/e' ratio were blowout time-Tissue (standard regression = - 0.27, t-value = - 2.90, p < 0.0001) and body mass index (BMI) (0.16, 2.05, p = 0.04). The factors that were shown to independently contribute to the LV mass were urinary albumin concentration (0.30, - 2.90, p < 0.0001), BMI (0.28, 4.09, p < 0.0001), differences of gender (men = 1, women = 0: 0.23, 3.28, p = 0.001), acceleration time index-Vessel (- 0.23, - 2.99, p = 0.003) and mean arterial blood pressure (0.17, 2.61, p = 0.01). Our results confirmed that parameters of the pulsatile flow form of ocular microcirculation obtained by LSFG are significantly correlated with the LV end-diastolic pressure ratio and LV mass.

Fluid intake restores retinal blood flow early after exhaustive exercise in healthy subjects

PURPOSE

It remains unclear whether rehydration restores retinal blood flow reduced by exhaustive exercise. We investigated the effect of fluid intake on retinal blood flow after exhaustive exercise.

METHODS

Blood flow in the inferior (ITRA) and superior temporal retinal arterioles (STRA) was measured before and after incremental cycling exercise until exhaustion in 13 healthy males. After the exercise, the subjects rested without drinking (control condition: CON) or with drinking an electrolyte containing water (rehydrate condition: REH) and were followed up for a period of 120 min. To assess the hydration state, the body mass was measured, and venous blood samples were collected and plasma volume (PV) was calculated.

RESULTS

Body mass decreased in CON after the trial [- 1.1 ± 0.1% (mean ± SE), p < 0.05]. PV was lower in CON than in REH during recovery. The ITRA and STRA blood flows decreased immediately after exercise from the resting baseline (ITRA; - 23 ± 4% in REH and - 30 ± 4% in CON, p < 0.05). The ITRA blood flow recovered baseline level at 15 min of recovery in REH (- 9 ± 3%, p = 0.5), but it remained reduced in CON (-14 ± 3%, p < 0.05). The STRA blood flow was higher in REH than in CON at 15 min (2 ± 3 vs. - 5 ± 3%, p < 0.05).

CONCLUSIONS

The results of this study suggest that the reduction in retinal blood flow induced by exhaustive exercise can be recovered early by rehydration.

Arterial stiffness shown by the cardio-ankle vascular index is an important contributor to optic nerve head microcirculation

PROPOSE

The purpose of this study was to determine whether there were significant correlations between the pulse waveform in the capillary area of the optic nerve head (ONH) microcirculation shown by laser speckle flowgraphy (LSFG) and parameters of the systemic condition, especially the cardio-ankle vascular index (CAVI).

METHOD

We studied 130 men (ages 60.5 ± 10.9 years) who visited the Vascular Function Section of the Department of Cardiovascular Center of Toho University Sakura Medical Center. We evaluated the skew and blowout time (BOT) - which are parameters of pulse waveform analyses - using LSFG in the capillary area of the ONH for each patient. The CAVI, the E/e' ratio as the measure of diastolic left ventricular function, and the mean intima-media thickness (IMT) were evaluated as systemic parameters. We performed a Pearson's correlation analysis and a multiple regression analysis to determine independent factors for skew and BOT.

RESULTS

Heart rate, spherical refraction, and the CAVI (standard regression = 0.18, t = 2.61, p = 0.01) were revealed as factors contributing independently to the skew by multiple regression analysis. Heart rate, the CAVI (standard regression = -0.27, t = -3.92, p = 0.0002), the urinary albumin concentration, the mean IMT, spherical refraction, body mass index and pulse pressure were revealed as factors contributing independently to the BOT by multiple regression analysis.

CONCLUSION

The CAVI was demonstrated to be an independent factor contributing to both skew and BOT in the capillary area of the ONH. Our findings clarified that large arterial function shown by the CAVI contributes to smooth hemodynamics of microcirculation, shown by LSFG.

Relationship between glycosylated hemoglobin A1c and ocular circulation by laser speckle flowgraphy in patients with/without diabetes mellitus

PURPOSE

To determine whether there are significant correlations between the hemodynamics of the optic nerve head (ONH) and choroid as shown by laser speckle flowgraphy (LSFG) and the fasting blood sugar (FBS) and HbA1c level in patients with/without diabetes mellitus (DM).

METHODS

We analyzed 196 consecutive patients (151 men, 45 women). The pulse waveform analysis parameters of the mean blur rate (MBR), blowout score (BOS) and blowout time (BOT) in the ONH and choroid were evaluated. We used a multiple regression analysis to determine the independent factors for the LSFG parameters that are significantly correlated with FBS or HbA1c. We evaluated the relationship between the LSFG parameters FBS and HbA1c obtained from the 147 non-DM patients.

RESULTS

The multiple regression analysis revealed that hematocrit and HbA1c were factors contributing independently to the choroid MBR. The age, gender, pulse pressure, heart rate, spherical refraction and HbA1c were identified as factors contributing independently to the BOS in the ONH. The multiple regression analysis indicated that age, height, pulse pressure, heart rate and HbA1c were factors contributing independently to the BOS in the choroid. A Pearson's correlation analysis showed that the BOT values in the ONH and choroid were significantly correlated with the HbA1c in the non-DM patients.

CONCLUSION

Our results confirmed that HbA1c, even within the normal range, affected the blood flow in the ONH and choroid. LSFG may be a useful method to detect abnormalities of asymptomatic ocular circulation.

Pulse waveform analysis in the optic nerve head circulation reflects systemic vascular resistance obtained via a Swan-Ganz catheter

PURPOSE

To determine whether a pulse waveform analysis in the optic nerve head (ONH) circulation as determined by laser speckle flowgraphy (LSFG) can provide systemic hemodynamic values - the systemic vascular resistance (SVR) in particular - similar to those obtained by using a Swan-Ganz catheter, which is an invasive method.

METHOD

Sixteen consecutive subjects were examined. Hemodynamic monitoring was obtained from right heart catheterization with a Swan-Ganz catheter and coronary angiography without an intracoronary nitroglycerin administration. Direct blood pressure was measured with a trans-radial approach. Single regression analyses were used to determine the relationship between the blowout score and blowout time, which are the items of the pulse waveform analysis in the ONH, by using LSFG and the hemodynamic parameters.

RESULTS

The blowout time was significantly and negatively correlated with the SVR (r = -0.52, p = 0.04), the ocular perfusion pressure with the mean arterial blood pressure of the radial artery (r = -0.52, p = 0.04) and the radial artery pulse pressure (r = -0.52, p = 0.04).The pulmonary capillary wedge pressure (r  = -0.44, p = 0.09) and the mean arterial blood pressure of the radial artery (r  = -0.44, p = 0.09) tended to be correlated with the blowout time, but did not reach significance. The blowout score was significantly and negatively correlated with the radial artery blood pressure (r = -0.51, p = 0.046).

CONCLUSION

A pulse waveform analysis in the ONH by LSFG may be one of the useful methods for understanding the SVR.

Pulse waveform analysis of optic nerve head circulation for predicting carotid atherosclerotic changes

PURPOSE

To evaluate the relationship between the parameters of pulse waveform analysis in the optic nerve head using laser speckle flowgraphy (LSFG) and intima-media thickness (IMT) and severity of carotid arterial plaque.

DESIGN

Prospective and cross-sectional study.

METHODS

One hundred seventy-six subjects were studied. Mean IMT and plaque score obtained from high-resolution B-mode ultrasound were evaluated. If mean IMT was 1 mm or greater, abnormal carotid artery thickening was diagnosed; if the plaque score exceeded 10, severe atherosclerosis was diagnosed. Blowout time and blowout score, which are parameters of pulse waveform analysis using LSFG, were evaluated. Logistic regression analyses determined the independent factors for abnormal carotid artery thickening and severe atherosclerosis. The cutoff levels for abnormal carotid artery thickening and severe atherosclerosis were analyzed using a conventional receiver operating characteristic (ROC) curve.

RESULTS

Logistic regression analysis showed that blowout time and body mass index contributed independently to abnormal carotid artery thickening, and blowout score contributed independently to severe atherosclerosis. The ROC curve showed that sensitivity and specificity of the blowout time and blowout score were equivalent to or greater than those of other factors. The cutoff level of the blowout time for abnormal carotid artery thickening was 46.4; the cutoff level of the blowout score for severe atherosclerosis was 71.8.

CONCLUSIONS

Measurement of blowout time and blowout score in the optic nerve head by LSFG can be useful for evaluating mean IMT and plaque score, which are parameters of carotid atherosclerosis.