Evaluation of optic nerve head and peripapillary retinal blood flow in glaucoma patients, ocular hypertensives, and normal subjects.

PURPOSE

To compare optic nerve head (ONH) and peripapillary retinal blood flow in subjects with open-angle glaucoma (OAG), ocular hypertension (OHT), and normal eyes (NOR) using full-field perfusion analysis of scanning laser Doppler flowmetry (SLDF) images.

DESIGN

Prospective, nonrandomized clinical trial.

METHODS

Twenty uncontrolled OAG patients, 20 uncontrolled OHT patients, and 20 normal volunteers were prospectively enrolled. Mean ONH and peripapillary retinal blood flow measurements were performed by SLDF version 3.3 using five Heidelberg Retina Flowmeter (Heidelberg Engineering, Heidelberg, Germany) images. Statistical evaluations were performed on the three study groups using one-way analysis of variance. Flow values of the neuroretinal rim of the ONH, nasal peripapillary retina, and temporal peripapillary retina were then correlated with the clinical parameters of age, cup/disk (C/D) ratio, intraocular pressure (IOP), visual field mean defect, maximum-recorded IOP, and ocular perfusion pressure. Neuroretinal rim blood flow in the OAG group was 158 +/- 79 arbitrary units (au), whereas in the OHT group it was 277 +/- 158 au, and in the NOR group it was 272 +/- 93 au. Differences were statistically significant between the OAG group and each of the other groups (P =.001) but not between OHT and NOR groups (P =.91). Peripapillary retinal flow values showed no statistically significant differences between groups (P =.76 nasal and 0.93 temporal).

RESULTS

Neuroretinal rim flow values showed a significant inverse correlation with C/D ratio (P =.001). Mean neuroretinal rim blood flow was significantly higher (350 +/- 184 au) in the 10 OHT patients with C/D ratios < 0.4 when compared with the 10 OHT patients with larger C/D ratios (203 +/- 79 au) (P =.039). Conversely, peripapillary retinal blood flow showed no significant correlation with any clinical parameter.

CONCLUSION

Open-angle glaucoma patients had significantly lower blood flow in the ONH compared with OHT patients and normal volunteers. No significant differences in ONH blood flow were found between ocular hypertensives and normal volunteers. For peripapillary retinal blood flow, no significant difference was seen between any groups. Neuroretinal rim blood flow was significantly inversely correlated to increased C/D ratio. Ocular hypertensives with larger C/D ratios demonstrated significantly lower rim blood flow compared with those with smaller C/D ratios, suggesting that rim perfusion might be reduced in high-risk ocular hypertensives before the manifestation of visual field defects.