Volumetric colour Doppler imaging: a useful tool for the determination of ocular blood flow in glaucoma patients?

12-month outcomes of ab interno excisional goniotomy combined with cataract surgery in primary open-angle glaucoma and normal tension glaucoma

PURPOSE

To evaluate the efficacy and safety of excisional goniotomy performed with the Kahook Dual Blade (KDB) combined with cataract surgery in patients with pimary open angle glaucoma (POAG) and Normal Tension Glaucoma (NTG) under topical therapy. Further sub-analysis was performed to compare between 90 and 120 degrees goniotomy.

METHODS

This was a prospective case series of 69 eyes from 69 adults (age 78 ± 5.9 years; male = 27, female = 42). Indications for surgery included insufficient IOP control with topical medication, glaucomatous damage progression under topical therapy and reduction of medication burden. Complete success was defined as IOP lowering below 21 mmHg without the need for topical medication. For NTG patients, complete success was defined as IOP lowering below 17 mmHg without the need for topical medication.

RESULTS

IOP was significantly lowered from 19.7 ± 4.7 to 15.1 ± 2.7 at 2 months, 15.8 ± 2.3 at 6 months and 16.1 ± 3.2 at 12 months (p < 0.05) for POAG and 15.1 ± 2.5 to 14.1 ± 2.4 at 2 months, 14.1 ± 3.1 at 6 months and 13.6 ± 1.8 at 12 months (p > 0.08) for NTG, respectively. Complete success was achieved in 64% of the patients. IOP lowering under 17 mmHg without the need for topical medication was achieved in 60% of the patients at 12 months. In NTG patients (14 eyes) IOP lowering under 17 mmHg without the need for topical medication was achieved in 71%. No significant difference was recorded in terms of IOP lowering at 12 months in-between 90° and 120° of treated trabecular meshwork (p > 0.7). No severe adverse reactions were recorded in this study.

CONCLUSION

One-year results show that KDB combined with cataract surgery is an effective treatment option for glaucoma patients. IOP lowering was successfully achieved in NTG patients with complete success in 70% of the patients. In our study, no significant differences were recorded in-between 90° and 120° of treated trabecular meshwork.

Ocular Hemodynamics in Acute Nonarteritic Anterior Ischemic Optic Neuropathy Compared With Normal Tension Glaucoma

PURPOSE

The purpose of this study was to evaluate ocular hemodynamics in patients with a disease believed to be related to a chronic vascular damage [ie, normal tension glaucoma (NTG)] in comparison with an entity with an acute ischemic impact on the optic nerve [ie, acute nonarteritic anterior ischemic optic neuropathy (NAION)].

MATERIALS AND METHODS

Blood-flow velocities [peak systolic velocity (PSV), enddiastolic velocity (EDV)] of the ophthalmic artery (OA), central retinal artery (CRA), and nasal and temporal posterior ciliary arteries were measured using color Doppler imaging. Resistive index (RI) of all vessels was calculated (PSV-EDV/PSV). A total of 41 patients suffering from acute NAION (onset of symptoms <10 d) and 64 age-matched patients suffering from NTG were included in this prospective study.

RESULTS

No significant differences were recorded for either age or intraocular pressure inbetween the 2 groups. Systolic blood pressure was significantly higher in the NAION group, whereas no significant differences were recorded for the diastolic blood pressure. Only 3 color Doppler imaging parameters were found to differ significantly. The PSV (P<0.005) and EDV (P<0.02) in the CRA were significantly higher in NTG patients. Furthermore, the RI in the OA was significantly higher in the NAION patients (P<0.005).

CONCLUSIONS

Decreased blood-flow velocities in the CRA and a higher RI in the OA can be recorded in NAION patients as compared with NTG. No differences with regard to the posterior ciliary arteries' velocities were recorded. Ocular hemodynamics are suspected to play a critical role in NAION and NTG, whereas the blood-flow disturbances seem to be more severe in NAION than in NTG.

Effects of dorzolamide/timolol fixed combination on retrobulbar hemodynamics in pseudoexfoliative glaucoma

In our study we aimed to evaluate the short-term effects of dorzolamide/timolol on ocular perfusion pressure and retrobulbar blood flow in patients with pseudoexfoliative glaucoma (PXG). This prospective observational cross-sectional study enrolled 22 eyes of 22 newly-diagnosed patients with PXG in a single center. All of the patients received a fixed combination of dorzolamide/timolol. Besides routine ophthalmologic examination, the retrobulbar hemodynamic parameters in the ophthalmic artery, central retinal artery, and short posterior ciliary arteries were measured in all participants at baseline and the 3(rd) month using color Doppler imaging. The mean intraocular pressure (IOP) was 22.3 ± 2.1 mmHg at baseline and reduced to 17.4 ± 2.3 mmHg at the 3(rd) month (p < 0.05). None of the retrobulbar parameters, except peak systolic velocity and resistive index in temporal short posterior ciliary arteries, changed significantly on therapy with dorzolamide/timolol fixed combination when the results were analyzed at Month 3. The drug significantly decreased the peak systolic velocity (p = 0.044) and reduced the resistive index in 0.04 units, 95% confidence interval 0.03-0.05, (p < 0.001) in the temporal short posterior ciliary arteries. This study reports that the retrobulbar hemodynamics might be affected less than expected by dorzolamide/timolol fixed combination in patients with PXG although the reduction of IOP was statistically significant.

Color Doppler Imaging Analysis of Ocular Blood Flow Velocities in Normal Tension Glaucoma Patients: A Meta-Analysis

Background. To evaluate the potential diagnostic value of CDI of retrobulbar hemodynamic changes in NTG patients. Methods. Relevant publications which included PSV, EDV, and RI of OA, CRA, NPCA, and TPCA in NTG patients and normal controls measured by CDI were retrieved from the Cochrane Central Register of Controlled Trials, PubMed, the ISI Web of Knowledge, and EMBASE from 1990 to 2014. Subgroup analyses were made based on IOP-lowering medications uses. Result. In OA, there was significant decrease of PSV with moderate heterogeneity (P < 0.00001, I (2) = 49%) and significant decrease of EDV with significant heterogeneity (P = 0.0005, I (2) = 87%) in NTG patients. In CRA, similar results of PSV (P < 0.00001, I (2) = 42%) and EDV (P < 0.00001, I (2) = 80%) were detected. Significant decrease of PSV and EDV with significant heterogeneity was also found in both NPCA (P < 0.0001, I (2) = 70%; P < 0.0001, I (2) = 76%; resp.) and TPCA (P < 0.00001, I (2) = 54%; P < 0.00001, I (2) = 65%; resp.). Statistically significant increases of RI were found in CRA (P = 0.0002, I (2) = 89%) and TPCA (P = 0.02, I (2) = 81%) with significant heterogeneities, though RI in OA (P = 0.25, I (2) = 94%) and in NPCA (P = 0.15, I (2) = 86%) showed no statistical changes with significant heterogeneities. Conclusions. Ischemic change of retrobulbar hemodynamics is one of the important manifestations of NTG. Hemodynamic parameters measured by CDI might be potential diagnostic tools for NTG.

Retrobulbar Hemodynamics and Visual Field Progression in Normal Tension Glaucoma: A Long-Term Follow-Up Study

Purpose. Vascular risk factors are important factors in the pathogenesis of glaucoma. The purpose of this research was to investigate retrobulbar hemodynamics and visual field progression in patients with normal tension glaucoma (NTG). Patients and Methods. 31 eyes of 16 patients with NTG were included in a retrospective long-term follow-up study. Colour Doppler imaging was performed at baseline to determine various CDI parameters in the different retrobulbar vessels. The rate of visual field progression was determined using the Visual Field Index (VFI) progression rate per year (in %). To be included in the analysis, patients had at least 4 visual field examinations with a follow-up of at least 2 years. Results. Mean follow-up was 7.6 ± 4.1 years with an average of 10 ± 5 visual field tests. The mean MD (mean defect) at baseline was −7.61 ± 7.49 dB. The overall VFI progression was −1.14 ± 1.40% per year. A statistical significant correlation between VFI progression and the RI of the NPCA and PSV of the CRA was found. Conclusion. Long-term visual field progression may be linked to impaired retrobulbar hemodynamics in patients with NTG only to a limited degree. Interpretation of the data for an individual patient seems to be limited due to the variability of parameters.

Use of colour Doppler imaging in ocular blood flow research

The main objective of this report is to encourage consistent quality of testing and reporting within and between centres that use colour Doppler imaging (CDI) for assessment of retrobulbar blood flow. The intention of this review is to standardize methods in CDI assessment that are used widely, but not to exclude other approaches or additional tests that individual laboratories may choose or continue to use.

Compromised Autoregulatory Control of Ocular Hemodynamics in Glaucoma Patients after Postural Change

PURPOSE

The autoregulatory control of retrobulbar blood flow in response to postural challenge was investigated in normal-tension glaucoma (NTG) patients in comparison with primary open-angle glaucoma (POAG) patients and healthy volunteers.

DESIGN

Prospective cohort study.

PARTICIPANTS AND CONTROLS

Twenty POAG patients, 20 NTG patients, and 20 control subjects.

METHODS

Peak systolic velocity (PSV), end diastolic velocity (EDV), and resistivity index (RI) in the short posterior ciliary artery (SPCA), central retinal artery (CRA) and ophthalmic artery (OA) were recorded after a change from sitting upright to a supine body position using color Doppler imaging.

MAIN OUTCOME MEASURES

Peak systolic velocity, EDV, and RI.

RESULTS

Ten minutes after postural change to a supine position, blood flow velocities in the SPCA remained unchanged in controls, whereas a significant increase of PSV and EDV was found in both glaucoma groups. The RI in the SPCA was significantly lowered in the NTG group. Recordings for the OA and CRA showed a significant increase in EDV and significant decrease in RI in all 3 groups; a significant increase in PSV in the CRA was detected only in the NTG group.

CONCLUSIONS

The unaltered flow velocities in the SPCA of healthy controls may indicate tight autoregulatory control, whereas the flow velocities in the CRA and OA appeared to follow alterations in hydrostatic pressure. In contrast, NTG and POAG patients demonstrated an insufficient compensatory response to postural change, leading to accelerated flow in the SPCA. This compromised autoregulatory control could represent another contributing factor in the pathogenesis of glaucoma.

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.