To analyze the value and difference of the optic nerve sheath pulse dynamic deformation index (DI) in normal-tension glaucoma (NTG) and high-pressure primary open angle glaucoma (POAG).
A cross-sectional study was conducted to collect clinical data at the Eye Center of Beijing Tongren Hospital from June 2016 to March 2017, 32 patients with NTG and 35 patients with high-pressure POAG were sampled.For all subjects, their basic information, body mass index (BMI), mean arterial blood pressure (MAP), 24 hours intraocular pressure, and ophthalmologic examinations required for diagnosis were recorded.All subjects underwent transorbital ultrasonography and for each 15 seconds of consecutive ultrasound images were taken.The dynamic post-processing technique was used to calculate the DI.The difference in DI between the two groups and the correlation of DI with other variables were analyzed.The study protocol was approved by the Ethics Committee of Beijing Tongren Hospital.Written informed consent was obtained from all subjects prior to their entering the study cohort and receiving the transorbital ultrasound examination.
The median level of DI in the NTG group was 0.51 (0.48, 0.54), which was higher than that in the high-pressure POAG group (0.23[0.20, 0.25]), exhibiting a significant difference (Z=-7.01, P<0.01). The mean BMI in the NTG group was lower than that in the high-pressure POAG group([21.29±4.64]kg/m2vs. [23.53±3.40]kg/m2), the mean MAP in the NTG group was lower than that in the high-pressure POAG group([91.44±14.30]mmHg vs. [104.05±13.96] mmHg), the differences between the two groups were statistically significant (t=-2.30, P<0.05; t=-3.65, P<0.01). There was no statistical association between the two groups of DI and age, MAP, BMI, mean intraocular pressure and maximum intraocular pressure (all at P>0.05).
The DI of the NTG patient is higher than that of the POAG patient, which indicates that the optic nerve sheath subarachnoid pressure and optic nerve sheath stiffness in NTG patients are lower than those in POAG patients.Therefore, the DI is a potential indicator of non-invasive intracranial pressure and translaminar cribrosa pressure difference detection in ophthalmology.