Vascular Risk Factors in Normal Tension Glaucoma

ABSTRACT

To evaluate the implication of vascular factor in normal tension glaucoma, authors performed color doppler imaging[CDI] for ophthalmic artery, central retinal artery and posterior ciliary artery in 21 eyes of 12 patients in normal tension glaucoma and 16 eyes of 11 patients in normal control group. We compared peak-systolic velocity[PSV], end-diastolic velocity[EDV], mean velocity[MV], resistance index[RI] and pulsatile index[PI] between the two groups. We evaluate the difference in parameters according to age, sex, systolic and diastolic blood pressure, past history of diabetes and hypertension, cup-disc ratio and visual field change. In normal tension glaucoma group, PSV, EDV and MV of ophthalmic artery and central retinal artery were significantly decreased and pulsatile index was significantly increased compared to those of normal group. Resistance index was also increased in normal tension glaucoma group, but statistically not significant. All parameters of posterior ciliary artery had no significant difference between the two groups. Age was related positively to pulsatile index and resistance index of central retianl artery and diastolic blood pressure was related positively to resistance index of ophthalmic artery. Cup-disc ratio was related negatively to PSV and EDV of ophthalmic artery. Above results imply that blood flow velocity decreased by increasing resistance factor in normal tension glaucoma, therefore local vascular factor might be related to the development of the normal tension glaucoma and affected by age, blood pressure and cup-disc ratio change.