Study of dynamic contour tonometry in normal tension glaucoma patients and primary open angle glaucoma

AIM: To survey the application of dynamic contour tonometer(DCT)in normal tension glaucoma(NTG)patients, primary open angle glaucoma(POAG)patients and healthy controls. And to analyze the factors that influence the ocular pulse amplitude(OPA). METHODS: In this case-control study, twenty NTG patients, twenty-one POAG patients and twenty health people were included in the study. Intraocular pressure(IOP)was measured in each group with GAT and DCT. Correlation between the value of IOP measured with DCT and GAT were analyzed. Meanwhile, central corneal thickness(CCT), axial length(AL), systolic blood pressure(SBP), diastolic blood pressure(DBP)and heart rate(HR)were also measured to evaluate the influencing factor of OPA. RESULTS: There were significant statistical differences of IOP, OPA, SBP and DBP among NTG patients, POAG patients and healthy controls. There were no significant statistical differences of CCT, AL and HR among those subjects. The OPA were 1.7±0.9mmHg in NTG patients, 2.8±0.7mmHg in POAG patients and 2.4±0.6mmHg in normal controls. There was no significant statistical difference of OPA between POAG patients and normal controls(P=0.502), whereas significant statistical difference of OPA between POAG patients and NTG patients(P=0.001)was observed. Significant statistical difference of OPA between NTG patients and normal controls(P=0.005)was detected. The results of Pearson correlation analysis showed that there was significant correlation between OPA with AL, SBP and DBP(P<0.05). No significant correlation was found between OPA with IOP, HR and CCT(P>0.05). CONCLUSION: There are differences of OPA among NTG patients, PAOG patients and normal controls. And OPA is influenced by AL, SBP and DBP.