Initial color Doppler findings in retinal vein occlusion

Elevated retinal artery vascular resistance determined by novel visualized technique of laser speckle flowgraphy in branch retinal vein occlusion

We aimed to investigate the increase in resistivity of the retinal artery in the branch retinal vein occlusion (BRVO)-affected area, and to visualize it. Thirty-two eyes of 32 patients with BRVO were measured by laser speckle flowgraphy (LSFG). The retinal artery and vein running to the BRVO-affected area and vertically symmetrical vessels in the unaffected area were examined. We applied the LSFG parameter beat strength over mean blur rate (BOM), calculated using a similar method to the pulsatility index used in Doppler flowmetry to evaluate resistivity of the vessels. Our results showed that the BOM map could clearly visualize the increase of resistivity in the retinal artery as a two-dimensional map. The BOM of the arteries in the affected area was significantly higher than that of the unaffected area (P = 0.001). Multiple regression analysis showed that the ratio of BOM in retinal arteries of the affected area to the unaffected was significantly associated with the extent of retinal hemorrhage (β = 0.447, P = 0.009). In conclusion, the index of resistivity of the retinal artery in the BRVO-affected area was higher and could be visualized in a two-dimensional map. These findings and techniques would contribute to elucidate the pathophysiology of BRVO.

Glaucoma as a prognostic factor of central retinal vein occlusion: visual and anatomical outcomes and occurrence of ischaemic central retinal vein occlusion

PURPOSE

To compare the functional and anatomical outcomes of central retinal vein occlusion (CRVO) according to the presence of glaucoma before the onset of CRVO, and to assess whether pre-existing glaucoma affects the prognosis of CRVO in terms of development and conversion to ischaemic CRVO.

METHODS

In this retrospective cohort study, patients with treatment-naïve CRVO were enrolled between December 2009 and February 2019. The patients were classified into two groups according to the presence of pre-existing primary open-angle glaucoma at CRVO diagnosis. We reviewed medical records regarding basic demographics, ocular characteristics and treatments. The effects of pre-existing glaucoma on the occurrence of ischaemic CRVO were also investigated using Cox proportional hazard models.

RESULTS

Of 166 eyes from 166 patients, 26 (15.7%) had pre-existing glaucoma. The pre-existing glaucoma group revealed significantly older (69.4 ± 13.3 versus 56.5 ± 15.9) and lower BCVA at baseline (1.06 ± 0.75 versus 0.64 ± 0.58, logMAR) and final visits (1.56 ± 1.35 versus 0.64 ± 0.48, logMAR) (all p < 0.05) than non-glaucomatous group. In terms of perfusion status of CRVO, the glaucoma group showed higher incidence of ischaemic CRVO (30.8% versus 5.3%, p = 0.052) at initial and last visits as well as more disorganization of retinal inner layers (DRIL) at 3 months (76.0% versus 49.6%, p = 0.015). Pre-existing glaucoma (hazard ratio (HR) = 2.141, p = 0.014), lower vision at baseline (HR = 2.071, p = 0.001) and DRIL at 3 months (HR = 2.905, p = 0.011) were significant risk factors for the occurrence of ischaemic CRVO.

CONCLUSION

In patients with CRVO, pre-existing glaucoma was associated with poorer visual and anatomical outcomes, and played as a significant risk factor for the development and conversion to ischaemic CRVO with lower vision and presence of DRIL at early phase of CRVO.

Current use of the automatic retinal oximetry. Review

PURPOSE

To inform about possible use of the automatic retinal oximetry for the retinal oxygen saturation measurement in the eye and systemic diseases.

METHODS

We performed a literature review dealing with issues of retinal oxygen saturation monitoring by dual non-invasive retinal oximetry Oxymap T1 (Oxymap ehf. Reykjavík, Iceland).

RESULTS

We have found two main strains writing our paper on retinal oxygen saturation eye diseases. The first section concerns diseases created by having hypoxia as its main pathological factor  - for example diabetes mellitus and retinal vein occlusion. The second group deals with atrophy as the main pathological mechanism which is typical for decreasing retinal oxygen consumption - for example glaucoma or retinitis pigmentosa (the second one named is not included in our work). Oximetry in systemic diseases creates a relatively new chapter of this branch with a very big potential of interdisciplinary cooperation for the future. It is possible the cooperation will not only include diabetologists but also neurologists (for example, in diseases like sclerosis multiplex or Devics, Alzheimers and Parkinsons disease) and haematologists (retinal oxygen saturation changes in patients with different rheological attributes of blood).

CONCLUSION

Retinal oxygen saturation measuring by automatic retinal oximetry is a relatively new method with scientifically confirmed high reproducibility of results. Currently it is the only experimental method with vast potentials not only in the realm of the possibility of observing eye diseases (diabetic retinopathy, retinal vein occlusion or glaucoma) but also in developing interdisciplinary cooperation with diabetologists, neurologists and haematologists.

The short-term effects of intravitreal aflibercept injections and dexamethasone implant on ocular hemodynamics in retinal vein occlusions

Purpose

To determine the early effects of intravitreal anti-VEGF and dexamethasone application on blood flow velocities in patients with retinal vein occlusions.

Methods

The ophthalmic (OA) and the central retinal arteries (CRAs) of the affected and unaffected eyes of 21 patients with central retinal vein occlusion (CRVO), and 26 patients with branch retinal vein occlusion (BRVO) were investigated by Color Doppler imaging (CDI). Peak systolic volume (PSV), end diastolic volume (EDV), and average blood velocity (Vmean) of the CRA and OA were measured and resistive indexes (RI) were calculated at pre-injection and the 1st week and 1st month post-injection.

Results

There was no statistically significant difference between the OA values for affected and unaffected eyes in the CRVO group before treatment. The CRA, EDV, and Vmean values were significantly lower in affected eyes. Blood flow velocities of both CRA and OA were not significantly different than in the fellow unaffected eyes in the BRVO group. The differences between PSV, EDV, and Vmean measurements of OA and CRA at different times pre- and post-injection in response to anti-VEGF and dexamethasone treatment in the CRVO group were significant; but there was no difference in RI value. OA blood flow velocity measurements were not statistically different post-injection in the BRVO group; however, the values of PSV and EDV of CRA decreased post-injection.

Conclusion

Intravitreal anti-VEGF and dexamethasone implant may induce retinal arteriolar vasoconstriction in patients with retinal vein occlusion.

The impact of intravitreal dexamethasone implant (Ozurdex®) on retrobulbar hemodynamics in patients with diabetic macular edema and retinal vein occlusions

Objective: To evaluate the effect of single intravitreal dexamethasone implant (Ozurdex^®) on ocular blood flow velocities in patients with diabetic macular oedema (DME) and retinal vein occlusions (RVO). Methods: This prospective non-randomized interventional study included injected and fellow eyes of 12 patients with DME and of 16 patients with RVO treated with intravitreal Ozurdex^®. Colour Doppler Ultrasonography (CDU) measures of the central retinal artery (CRA), posterior ciliary artery (PCA), ophthalmic artery (OA) those are peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI) and pulsatility index (PI) were performed in both injected and uninjected eyes before injection, at one week, one month after injection, and prior to re-injection. Results: Inter-eye comparison of all the measured CDU data (baseline, first week, first month, reinjection) showed no statistically significant difference in both DME and RVO group. PSV and EDV values of the CRA, OA, and PCA showed a decreasing trend in the first week and first-month visits and then increased at reinjection time. RI and PI measures of the CRA, OA, and PCA measures showed minimal alterations in the follow-up. But all these differences were not statistically significant. Significant visual gain and anatomic recovery were obtained by the intravitreal dex-implant both in the DME and RVO group. Conclusions: Single intravitreal dex-implant did not alter ocular blood flow in the treatment of macular oedema due to RVO and diabetes.

Disorganization of Retinal Inner Layers and Ellipsoid Zone Disruption Predict Visual Outcomes in Central Retinal Vein Occlusion

PURPOSE

To assess the associations and predictive value of spectral-domain (SD) OCT inner and outer retinal structural parameters and visual acuity (VA) outcomes in macular edema (ME) secondary to central retinal vein occlusion (CRVO).

DESIGN

Retrospective, longitudinal cohort study.

PARTICIPANTS

Eighty-four patients with ME secondary to CRVO receiving pro re nata anti-vascular endothelial growth factor (VEGF) therapy at 3 tertiary-level retina referral centers.

METHODS

In all participants, VA, demographic and clinical parameters, and SD OCT images from baseline, 3 months, and 12 months were reviewed. Spectral-domain OCT-based morphologic features in the 1500-μm foveal zone were analyzed by masked graders for disorganization of the retinal inner layers (DRIL), ellipsoid zone (EZ) and external limiting membrane disruption, cone outer segment tip (COST) visibility, cysts, subretinal and intraretinal fluid, and epiretinal membranes.

MAIN OUTCOME MEASURES

Spectral-domain OCT-based retinal structural parameters and VA outcomes.

RESULTS

In multivariate analyses adjusting for baseline VA, worsening VA over 1 year was associated with 1-year increases in DRIL (point estimate, 0.06 per 100 μm; P < 0.001) and EZ disruption (0.07 per 100 μm; P = 0.023), but decreased COST visibility (-0.09 per 100 μm; P = 0.018). A 3-month increase in DRIL (0.05 per 100 μm; P = 0.003) and EZ disruption (0.10 per 100 μm; P < 0.001) were the only factors predicting VA worsening over 1 year, after controlling for baseline VA. A multivariate model including 3-month evolution in DRIL, EZ disruption, and VA accounted for 86.3% of variability in 1-year VA change. Absolute differences between predicted and actual 1-year VA were within 2 lines in 80.9%. When DRIL increased by 250 μm or more over 3 months, no eyes showed VA improvement of 1 line or more in 1 year. When EZ disruption decreased by 250 μm or more over 3 months, no eyes worsened by 1 line or more over 1 year.

CONCLUSIONS

Early recovery over 3 months in both DRIL and EZ parameters are key drivers of 1-year VA outcomes. Predictive models incorporating 3-month changes in DRIL and EZ disruption support their usefulness as potential robust determinants of future VA.

Colour Doppler analysis of ophthalmic vessels in the diagnosis of carotic artery and retinal vein occlusion, diabetic retinopathy and glaucoma: systematic review of test accuracy studies

Background

Colour Doppler analysis of ophthalmic vessels has been proposed as a promising tool in the diagnosis of various eye diseases, but the available diagnostic evidence has not yet been assessed systematically. We performed a comprehensive systematic review of the literature on the diagnostic properties of Colour Doppler imaging (CDI) assessing ophthalmic vessels and provide an inventory of the available evidence.

Methods

Eligible papers were searched electronically in (Pre) Medline, Embase and Scopus, and via cross-checking of reference lists. The minimum requirement to be included was the availability of original data and the possibility to construct a two-by-two table. Study selection, critical appraisal using the QUADAS II instrument and extraction of salient study characteristics was made in duplicate. Sensitivity and specificity was computed for each study.

Results

We included 11 studies (15 two-by-two tables) of moderate methodological quality enrolling 820 participants (range 30 to 118). In 44.4% participants were female (range 37–59% in specific subgroups). CDI was assessed for internal carotid stenosis, diabetic retinopathy, glaucoma, and branch or central retinal vein occlusion diagnosis. There was insufficient data to pool the results for specific illnesses. For the assessments of ophthalmic arteries, mean sensitivity was 0.69 (range 0.27–0.96) with a corresponding mean specificity of 0.83 (range 0.70–0.96). Mean sensitivity of the central retinal artery assessments was 0.58 (range 0.31–0.84) and the corresponding mean specificity was 0.82 (range 0.63–0.94).

Conclusions

Robust assessments of the diagnostic value of colour Doppler analysis remain uncommon, limiting the possibilities to extrapolate its true potential for clinical practice.

PROSPERO 2014:CRD42014014027.

Gender differences in ocular blood flow

Gender medicine has been a major focus of research in recent years. The present review focuses on gender differences in the epidemiology of the most frequent ocular diseases that have been found to be associated with impaired ocular blood flow, such as age-related macular degeneration, glaucoma and diabetic retinopathy. Data have accumulated indicating that hormones have an important role in these diseases, since there are major differences in the prevalence and incidence between men and pre- and post-menopausal women. Whether this is related to vascular factors is, however, not entirely clear. Interestingly, the current knowledge about differences in ocular vascular parameters between men and women is sparse. Although little data is available, estrogen, progesterone and testosterone are most likely important regulators of blood flow in the retina and choroid, because they are key regulators of vascular tone in other organs. Estrogen seems to play a protective role since it decreases vascular resistance in large ocular vessels. Some studies indicate that hormone therapy is beneficial for ocular vascular disease in post-menopausal women. This evidence is, however, not sufficient to give any recommendation. Generally, remarkably few data are available on the role of sex hormones on ocular blood flow regulation, a topic that requires more attention in the future.

Hemodynamic response to intravitreal triamcinolone in eyes with macular edema

PURPOSE

To assess ocular hemodynamic response to intravitreal triamcinolone in patients with macular edema due to diabetes or retinal vein occlusion.

METHODS

Forty-three patients that were injected by intravitreal triamcinolone acetonide (0.1 cc 4 mg) for unilateral macular edema due to diabetes mellitus (n = 17) and occlusion of retinal vein (n = 26) underwent ocular hemodynamic evaluation by color Doppler imaging (CDI) before and one, two and three months after injection. Non-injected fellow eyes as well as 16 healthy volunteers were also evaluated.

RESULTS

In patients with diabetic macular edema, there was no hemodynamic difference between eyes to be injected and non-injected at baseline (P > 0.23). Compared to controls, a significant difference existed in the ophthalmic artery resistant index (P = 0.001) and end-diastolic velocity (P < 0.001) in diabetics. At one month, compared to fellow eyes, change in end diastolic velocity from baseline in treated eyes was significantly decreased in posterior ciliary arteries (0.68 +/- 0.34 cm/s [mean +/- SEM] vs. -1.04 +/- 0.81 cm/s, P = 0.012). Throughout the study period, no significant alteration from baseline in the resistant index of any artery was noted in treated diabetic eyes (P > 0.05). In eyes with retinal vein occlusion, baseline CDI evaluation demonstrated reduced posterior ciliary arteries systolic flow velocity compared to fellow and control eyes (13.24 +/- 1.04 cm/s, 16.37 +/- 0.76 cm/s and 14.33 +/- 1.41 cm/s, respectively, P = 0.007). Increased peak systolic velocity in the posterior ciliary arteries at one week (P = 0.02), one month (P = 0.005) and two months (P = 0.04), and increase in central retinal artery resistant index at one month was noted (P = 0.05).

CONCLUSION

Intravitreal triamcinolone temporarily changed central retinal artery blood flow and posterior ciliary arteries' peak systolic blood velocity in eyes with retinal vein occlusion whilst no response of blood flow to triamcinolone injection but only transiently altered end diastolic blood velocity in posterior ciliary arteries was observed in diabetic eyes.

Early increase of retinal arterial and venous blood flow velocities at color Doppler imaging in brittle type 1 diabetes after islet transplant alone

Little information is currently available about the role of islet transplantation alone (ITA) on the retinal microcirculation. Our purpose was to investigate with color-Doppler-imaging the effect of ITA after one year on the blood flow velocities of central retinal artery and vein. Central retinal arteries and veins of both eyes of 10 ITA patients were evaluated with color-Doppler-imaging before and one year after transplant. Peak systolic velocity (psv), end diastolic velocity (edv) for arteries and maximum velocity (maxv), minimum velocity (minv) for veins were recorded and compared with a control group of type 1 diabetic patients. At one year, a statistically significant increase of blood flow velocities of central retinal arteries (psv: 6.09+/-0.46 vs. 10.12+/-1.20 cm/s, P=0.01) and veins (maxv: 3.12+/-0.28 vs. 6.12+/-1.00 cm/s, P=0.01) was found only in the ITA patients. An early, significant increase of arterial and venous retinal blood flow velocities was found after ITA.

Systolodiastolic variations of blood flow during central retinal vein occlusion: exploration by dynamic angiography

BACKGROUND/AIM

In patients with acute central retinal vein occlusion (CRVO), dynamic angiography may reveal the presence of pulsatile flow (termed here pulsatile venular outflow, PVO) within first order veins (that is, the large veins). The main goal of this study was to investigate the mechanism underlying PVO.

METHODS

10 patients with CRVO and PVO were included. Quantitative and qualitative analysis of venous flow on dynamic angiograms allowed the correlation, temporally, of second and first order vein flow on the one hand, and venous flow and systolic cycle on the other.

RESULTS

Analysis of the time-velocity curve showed that (1) the onset of arterial systole preceded the onset of PVO by less than 0.08 seconds (n = 5); (2) PVO onset was simultaneous to the time of onset of minimal flow (Vmin) in first order veins (n = 10); (3) the time of onset of maximal flow (Vmax) in first order veins occurred 0.20-0.44 seconds after the onset of PVO (n = 6).

CONCLUSIONS

During CRVO with severe reduction in blood flow, the presence of PVO is the result of the existence of a distinct haemodynamic regimen in first and second order veins. These data support the hypothesis that second order veins flow is synchronous with the arterial flow, while the delayed peak flow in first order veins may reflect the consequences of the delayed IOP curve and/or of intermittent venous compression.

Color Doppler imaging of orbital vessels: personal experience and literature review

Many Doppler imaging studies have been performed in recent years in a large number of ocular disorders because of improvements in the Doppler equipment used for detecting and measuring the low blood-flow velocities that are a requisite for the quantitative evaluation of blood flow in the orbital vessels. The ophthalmic artery, central retinal artery and vein, posterior ciliary arteries, and the superior ophthalmic vein can be easily identified using color Doppler sonography. The changes in local blood flow in these vessels assessed by spectral analysis pulsed Doppler sonography have been used to characterize and to obtain new insights into different nontumoral vascular disorders including carotid artery stenosis, central retinal vein occlusion, giant cell arteritis, glaucoma, diabetes, fistulas, and tumoral processes of the eye and orbit. Our experience has confirmed the important role of Doppler sonography in the assessment of subclinical changes in the vascular bed, in the understanding of different processes, for following up after specific treatments, and for determining the long-term prognosis of these various conditions.

Follow up by colour Doppler imaging of 102 patients with retinal vein occlusion over 1 year

BACKGROUND/AIM

Retinal vein occlusion (RVO) is one of the most frequent ocular vascular diseases and leads to severe vision impairment. Colour Doppler imaging (CDI) is the first method which allows distinct evaluation of arterial and venous velocities in RVO. CDI is valuable for diagnosis of RVO and shows the effects of isovolaemic haemodilution. Patients with RVO were monitored by CDI for 1 year in order to clarify venous and arterial involvement in the pathogenesis of this disease.

METHODS

Patients with RVO were monitored prospectively for 1 year with clinical examinations, fluorescein angiography, and CDI every 3 months. 102 adults referred for RVO for less than 2 months were enrolled. Unaffected eyes were used as control. The maximum systolic and diastolic flow velocities and the resistance index (RI) were measured in the central retinal artery (CRA) and the maximum and minimum blood flow velocities in the central retinal vein (CRV).

RESULTS

During the year of observation, branch retinal vein occlusion (BRVO), ischaemic central retinal vein occlusion (CRVO), and non-ischaemic CRVO had a distinct pattern of venous velocity changes. BRVO had a similar profile to that observed in controls. Venous velocities were continuously lower in central forms, with the lowest values in ischaemic occlusion. In contrast, a brief decrease in arterial diastolic velocity was observed in ischaemic CRVO at presentation, correlated with arteriovenous passage time on fluorescein angiography, but with rapid normalisation.

CONCLUSIONS

CDI findings were correlated with the type of RVO at all times during follow up. CDI showed persistent impairment of central venous velocity in CRVO whereas there was a fast initial values recovery of the arterial velocity. These results using CDI show strong evidence of a primary venous mechanism in RVO.