Normal neonatal values of ophthalmic and central retinal artery blood flow velocities

Retinal blood flow association with age and weight in infants at risk for retinopathy of prematurity

This prospective study evaluated the relationship between laser speckle contrast imaging (LSCI) ocular blood flow velocity (BFV) and five birth parameters: gestational age (GA), postmenstrual age (PMA) and chronological age (CA) at the time of measurement, birth weight (BW), and current weight (CW) in preterm neonates at risk for retinopathy of prematurity (ROP). 38 Neonates with BW < 2 kg, GA < 32 weeks, and PMA between 27 and 47 weeks underwent 91 LSCI sessions. Correlation tests and regression analysis were performed to quantify relationships between birth parameters and ocular BFV. Mean ocular BFV index in this cohort was 8.8 +/- 4.0 IU. BFV positively correlated with PMA (r = 0.3, p = 0.01), CA (r = 0.3, p = 0.005), and CW (r = 0.3, p = 0.02). BFV did not correlate with GA nor BW (r = - 0.2 and r = - 0.05, p > 0.05). Regression analysis with mixed models demonstrated that BFV increased by 1.2 for every kilogram of CW, by 0.34 for every week of CA, and by 0.36 for every week of PMA (p = 0.03, 0.004, 0.007, respectively). Our findings indicate that increased age and weight are associated with increased ocular BFV measured using LSCI in premature infants. Future studies investigating the associations between ocular BFV and ROP clinical severity must control for age and/or weight of the infant.

Retinal blood flow association with age and weight in infants at risk for retinopathy of prematurity

This prospective study evaluated the relationship between laser speckle contrast imaging (LSCI) ocular blood flow velocity (BFV) and five birth parameters: gestational age (GA), postmenstrual age (PMA), and chronological age (CA) at the time of measurement, birth weight (BW), and current weight (CW) in preterm neonates at risk for retinopathy of prematurity (ROP).38 Neonates with BW < 2 kg, GA < 32 weeks, and PMA between 27-47 weeks underwent 91 LSCI sessions. Correlation tests and regression analysis were performed to quantify relationships between birth parameters and ocular BFV. Mean ocular BFV index in this cohort was 8.8 +/- 4.0 IU. BFV positively correlated with PMA (r = 0.3, p = 0.01), CA (r = 0.3, p = 0.005), and CW (r = 0.3, p = 0.02). BFV did not correlate with GA nor BW (r=-0.2 and r=-0.05, p > 0.05). Regression analysis with mixed models demonstrated that BFV increased by 1.2 for every kilogram of CW, by 0.34 for every week of CA, and by 0.36 for every week of PMA (p = 0.03, 0.004, 0.007, respectively). Our findings indicate that increased age and weight are associated with increased ocular BFV measured using LSCI in premature infants. Future studies investigating the associations between ocular BFV and ROP clinical severity must control for age and/or weight of the infant.

Intravitreal bevacizumab treatment reduces ocular blood flow in retinopathy of prematurity: a four-case report

PURPOSE

To evaluate the relationship between ocular blood flow, expressed as mean blur rate (MBR) by laser speckle flowgraphy, and intravitreal bevacizumab (IVB) therapy in neonates with retinopathy of prematurity (ROP).

METHODS

This was a case series study of 4 neonates with ROP under sedation before and after IVB and evaluated 8 eyes, in which the circulation could be measured three times consecutively. We performed optic nerve head blood flow measurement and fluorescein angiography (FA) before and 1 week after treatment. Blood flow was analyzed separately for MBR-A (mean of all values), MBR-V (vessel mean), and MBR-T (tissue mean). Comparisons between the MBR (-A, -V, -T), body weight, and other systemic and ocular parameters before and after treatment were performed using a paired t test.

RESULTS

The MBR values after IVB were lower than the pre-treatment values in all cases. All eyes showed leakage at neovascularization on FA before treatment. Although leakage improved 1 week after treatment, the neovascularization did not completely regress.

CONCLUSIONS

IVB improves vein dilation and artery tortuosity, while reducing ocular blood flow in neonates with ROP. We suggest that neovascularization might not be involved in reducing ocular blood flow in the early stage of IVB treatment.

Decreased ocular blood flow after photocoagulation therapy in neonatal retinopathy of prematurity

PURPOSE

To evaluate the relationships between optic nerve head blood flow, expressed as mean blur rate (MBR) measured by laser speckle flowgraphy (LSFG), and photocoagulation therapy in neonates with retinopathy of prematurity (ROP).

STUDY DESIGN

Case series study.

METHODS

We studied 5 ROP neonates either during sleep or under sedation both before and after photocoagulation, and evaluated 8 eyes in which the circulation could be measured three times consecutively. Correlations between the MBR-A (mean of all values), MBR-V (vessel mean) and MBR-T (tissue mean) and postmenstrual age were evaluated using Spearman's rank correlation coefficient. In addition, correlations between the relative MBR (-A, -V, -T) value and number of photocoagulation burns and the NV score were evaluated. Differences between post-treatment MBR in ROP subjects and normal neonates' MBR were estimated using analysis of covariance (ANCoVA), with adjustment for postmenstrual age.

RESULTS

The relative MBR (-A, -V, -T) values after photocoagulation were 69.6 ± 16.0%, 66.7 ± 17.0% and 74.3 ± 14.6%, respectively. Postmenstrual age was significantly correlated with post-treatment MBR-A (r = 0.83, p = 0.0101), MBR-V (r = 0.85, p = 0.007) and MBR-T (r = 0.76, p = 0.0282). The relative MBR-T value was significantly correlated with the number of photocoagulation burns (r = -0.75, p = 0.033) and NV score (r = -0.72, p = 0.0437). The ANCoVA results showed no significant difference between post-treatment MBR and normal neonates' MBR.

CONCLUSIONS

Photocoagulation improved the dilation of veins and tortuosity of arteries and reduced ocular blood flow in ROP subjects. Since the post-treatment MBR was not different from a normal neonate's MBR, it is suggested that the pre-treatment MBR was higher in severe ROP cases.

Effect of Intravitreal Aflibercept on Central Retinal Arterial Blood Flow in Type 1 Retinopathy of Prematurity

Purpose

To evaluate the blood flow changes of the central retinal artery measured with color Doppler imaging (CDI) in infants receiving intravitreal aflibercept (IVA) for treatment of type 1 retinopathy of prematurity (ROP).

Methods

Patients with type 1 ROP were assessed prospectively by CDI following IVA. Color Doppler imaging was used to measure the peak systolic velocity, end diastolic velocity (EDV), pulsatility index (PI), and resistivity index (RI) of the central retinal artery (CRA) before IVA injection and 1 hour, 1 week, and 1 month after injection.

Results

A total of 29 eyes of 15 infants were included in this study. The mean gestational age at birth was 28.62 ± 2.48 weeks and the mean birthweight was 1,198.62 ± 348.99 g. All treated eyes showed complete regression of ROP and peripheral retinal vascularization continued. Measurements of EDV-CRA, RI-CRA, and PI-CRA showed significant changes after IVA treatment.

Conclusions

This study showed that IVA is an effective treatment for type 1 ROP. After IVA treatment, vascular resistance increases, ocular blood flow decreases, and changes in hemodynamic parameters of CRA may remain for a month. Further studies are needed to evaluate the effect of anti-vascular endothelial growth factor agents on ocular hemodynamics in infants with ROP.

Ocular blood flow values measured by laser speckle flowgraphy correlate with the postmenstrual age of normal neonates

PURPOSE

To evaluate the relationships between optic nerve head (ONH) blood flow by laser speckle flowgraphy (LSFG), and postmenstrual age and body weight in normal neonates.

METHODS

During their normal sleep, we studied 24 infants (postmenstrual age, 248-295 days) whose ocular blood flow could be measured three consecutive times. While the subjects slept in the supine position, three mean blur rate (MBR) values of the ONH were obtained: the MBR-A (mean of all values), MBR-V (vessel mean) and MBR-T (tissue mean) in the ONH. With regard to eye diseases, no retinopathy of prematurity (ROP) was observed, and no severe systemic diseases requiring treatment were noted in the subjects. Pearson's correlation coefficients were used to determine the relationship between the MBR-A, -V, -T and postmenstrual age (days) and body weight (g).

RESULTS

Postmenstrual age was significantly correlated with MBR-A (r = 0.64, p = 0.0007), MBR-V (r = 0.62, p = 0.0012) and MBR-T (r = 0.62, p = 0.0012). However, the body weight was not correlated with the MBR (MBR-A: r = 0.37, p = 0.07, MBR-V: r = 0.31, p = 0.14, MBR-T: r = 0.38, p = 0.06).

CONCLUSIONS

Our results clarified that the values of ocular blood flow measured by LSFG correlate with the postmenstrual age of normal neonates.

Longitudinal assessment of plus disease in retinopathy of prematurity using color Doppler imaging

Retinal vascular changes and the development of plus disease are the hallmarks of retinopathy of prematurity (ROP). The purpose of this study was to evaluate whether or not serial examinations of retrobulbar blood flow characteristics, as measured by color Doppler imaging (CDI) performed repeatedly over a period of several weeks, would be useful for predicting those infants at risk for developing plus disease and to determine whether this technique may be used as an objective tool for confirming the presence of plus disease. Of the 73 infants followed in this study, 14 (19%) developed plus disease confirmed by a panel of experts. When comparing the group of infants developing plus disease with those infants who did not develop plus disease, we did not find any significant differences in the retrobulbar blood flow characteristics of either the central retinal or ophthalmic arteries. Color Doppler imaging did not appear to be a clinically useful tool in the longitudinal management of ROP, nor did it appear to be useful as an objective determinant of plus disease in these premature infants.

Color Doppler orbital hemodynamics in healthy individuals and patients with vascular disorders in Taiwan

The main purpose of this study was to establish a data bank of orbital vasculature hemodynamics as assessed by color Doppler imaging (CDI) for normal Taiwanese. In addition, we compared the hemodynamic variables in subjects with a healthy orbital vasculature and 10 patients with various orbital disorders. From 1994 to 1995, we collected data from 90 age-and gender-matched (43 males, 47 females) healthy individuals, with age stratified by decades (ranging from 4 to 79 years). Ten patients with various orbital lesions were also examined by CDI. Peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (MV), pulsatility index (PI), and resistivity index (RI) were obtained for the ophthalmic, central retinal, and posterior ciliary arteries. The MV was also measured in the ophthalmic, central retinal, and vortex veins. The mean and standard deviation of the values were calculated for each decade of age. There was no correlation between the CDI-generated values and gender. Student's t-test showed that the flow velocity in the group below age 10, compared with that of the other groups, is significantly higher (p < 0.05). The CDI values in diseased orbits could be classified as hyper-, iso-, or hypovascular in comparison with healthy orbits. On linear regression, there was a correlation between age and the PSV, EDV, and MV of healthy ophthalmic arteries.