Color Doppler imaging analysis of retrobulbar blood flow velocities in primary open-angle glaucomatous eyes: a meta-analysis

Abstract

Background: To analyze the diagnostic value of color Doppler imaging (CDI) of blood flow in the retrobulbar vessels of eyes with primary open-angle glaucoma (POAG).

Methods: Pertinent publications were retrieved from the Cochrane Central Register of Controlled Trials, PubMed and the ISI Web of Knowledge up to October 2012. Changes in peak systolic velocity (PSV), end diastolic velocity (EDV) and resistive index (RI) of the ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary artery (SPCA) of POAG eyes and normal controls were evaluated by CDI. Subgroup analyses were conducted according to whether patients received IOP-lowering drugs treatment and were defined as treated and untreated.

Results: PSV and EDV were statistically significantly reduced in the OA of POAG eyes (P = 0.0002; P<0.00001; respectively), with significant heterogeneity (P(heterogeneity)<0.00001, I² = 94%; P(heterogeneity)<0.00001, I² = 85%; respectively). Similar results were demonstrated for the CRA (P<0.00001; respectively) and SPCA (P = 0.005; P<0.00001; respectively), with significant heterogeneities for both the CRA (P(heterogeneity)<0.00001, I² = 81%; P(heterogeneity)<0.00001, I² = 98%; respectively) and the SPCA (P(heterogeneity)<0.00001, I² = 96%; P(heterogeneity)<0.00001, I² = 93%; respectively). Significant increases in RI were found in all retrobulbar vessels (P<0.00001; respectively), with significant heterogeneities (P(heterogeneity)<0.00001, I² = 95%; P(heterogeneity)<0.00001, I² = 94%; P(heterogeneity)<0.00001, I² = 97%; respectively).

Conclusions: This meta-analysis suggests that CDI is a potential diagnostic tool for POAG.

Figure 1. Flowchart of the literature selection process.

Figure 2. Results of PSV in OA.

The forest plot showed the studies’ MDs in PSV in cm/s along with their associated 95%CIs, comparing POAG eyes with normal controls. PSV was significantly decreased in OA in POAG eyes. Subgroup analysis showed that the heterogeneity in OA was due to both the untreated and IOP-lowering drugs treatment subgroup. Negative values favored POAG eyes over normal controls; positive values favored normal controls over POAG eyes.

Figure 3. Results of PSV in CRA.

PSV was significantly decreased in CRA. Subgroup analysis showed that the heterogeneity in CRA was due to both the untreated and IOP-lowering drugs treatment subgroup.

Figure 4. Results of PSV in SPCA.

PSV was significantly decreased in SPCA. Subgroup analysis showed that the heterogeneity in SPCA was due to both the untreated and IOP-lowering drugs treatment subgroup.

Figure 5. Results of EDV in OA.

The forest plot showed the studies’ MDs in EDV in cm/s along with their associated 95%CIs, comparing POAG eyes with normal controls. EDV was significantly decreased in OA in POAG eyes. Subgroup analysis showed the heterogeneity in OA was due to both the untreated and IOP-lowering drugs treatment subgroup. Negative values favored POAG eyes over normal controls; positive values favored normal controls over POAG eyes.

Figure 6. Results of EDV in CRA.

EDV was significantly decreased in CRA in POAG eyes. Subgroup analysis showed the heterogeneity in CRA was due to both the untreated and IOP-lowering drugs treatment subgroup.

Figure 7. Results of EDV in SPCA.

EDV was significantly decreased in SPCA in POAG eyes. Subgroup analysis showed the heterogeneity in SPCA was due to both the untreated and IOP-lowering drugs treatment subgroup.

Figure 8. Results of RI in OA.

The forest plot showed the studies’ MDs in RI along with their associated 95%CIs, comparing POAG eyes with normal controls. RI was significantly increased in OA in POAG eyes. Subgroup analysis demonstrated the heterogeneity in OA was due to the IOP-lowering drugs treatment. Negative values favored POAG eyes over normal controls; positive values favored normal controls over POAG eyes.

Figure 9. Results of RI in CRA.

RI was significantly increased in CRA in POAG eyes. Subgroup analysis demonstrated the heterogeneity in CRA was due to the IOP-lowering drugs treatment.

Figure 10. Results of RI in SPCA.

RI was significantly increased in SPCA in POAG eyes.