Abstract
Abstract: :
Purpose:To measure the retrobulbar circulation in a large sample of subjects affected by either (a) ocular hypertension (OHT) or (b) primary open angle glaucoma (POAG) and to compare the results with those obtained in normal controls. Methods:A multi-center, cross-sectional investigation was performed in 7 centers in Italy. Eligibility criteria were as follows. Normal group: (a) normal optic disc, (b) normal computer-assisted perimetry (24/2 HFA), (c) IOP 22 mmHg on repeated evaluation. POAG: (a) glaucomatous optic disc (b) visual field defect (abnormal GHT and CPSD on 24/2 HFA) (c) IOP ≷ 22 mmHg without medical treatment. Exclusion criteria: (a) previous ocular surgery, (b) history of neuro-ophthalmological disorders (c) high myopia. Color Doppler Imaging (CDI) of ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCA) was performed by means of a standard 7.5 MHz probe on patients in supine position. Blood pressure and heart rate were monitored through the examination. Parametric statistics was adopted for comparison between means (two-tailed, independent Student "t" test). Results:414 subjects, 152 controls, 139 POAG and 123 OH were enrolled. The following results were obtained: OA RI: 0.72+0.06 (normals), 0.70+0.06 (OHT), 0.71+0.12 (POAG). CRA RI: 0.68+0.1 (normals), 0.72+0.2 (OHT), 0.72+0.12 (POAG). SPCA RI: 0.65+0.09 (normals), 0.69+0.07 (OHT), 0.70+0.1 (POAG) in the right eye. OA RI: 0.72+0.06 (normals), 0.71+0.05 (OHT), 0.71+0.07 (POAG). CRA RI: 0.70+0.11 (normals), 0.71+0.11 (OHT), 0.75+0.11 (POAG). SPCA RI: 0.64+0.1 (normals), 0.68+0.07 (OHT), 0.71+0.09 (POAG) in the left eye. The differences proved significant between normals and POAG for SPCA and CRA; between normals and OHT for SPCA; between OHT and POAG for SPCA and CRA in the left eye only. Conclusion:This large data sample, collected on a multi-center setting, shows an association between POAG and retrobulbar vascular impairment. Although this study cannot rule out the possibility that such an impairment is related to a loss of vascular bed in POAG, the CDI findings in OHT may support the hypothesis that vascular changes occur before an optic disc damage is clinically apparent.
Keywords: 355 clinical (human) or epidemiologic studies: risk factor assessment • 331 blood supply • 430 imaging/image analysis: clinical