New options for the diagnosis of normal tension glaucoma in the light of Professor V.V. Volkov’s concept of its pathogenesis

Abstract

PURPOSE:To measure lamina cribrosa thickness (LCT) and lamina cribrosa depth (LCD), optic nerve subarachnoid space width (ONSASW) in patients with normal tension glaucoma and in healthy individuals and to compare these data with the results of our own pilot study.
 MATERIALS AND METHODS:The 1st group included 13 patients (22 eyes) with normal tension glaucoma aged 39 to 88 years (59.8 10.9 years). The 2nd (control) group included 10 healthy people (20 eyes) aged 40 to 59 years (47.9 5.5 years). All subjects underwent structural and functional assessment of the optic nerve head using optical coherent tomograph (OCT) RTVue-100 (Optovue, USA), Humphrey perimeter (HFA II 745i, Germany-USA), and our own modification of Frequency Doubling Technology perimetry. LCT and LCD were measured by OCT RS-3000 Advance (Nidek, Japan). To measure ONSASW we used a cross-sectional image of the optic nerve taken with Magnetic Resonance Imaging (GE Optima MR450w MRI, USA).
 RESULTS:Differences in the 1st and 2nd groups between the mean values of LCT (234.14 27.73 and 336.25 21.0 m, respectively;p= 0.0000), LCD (461.8 101.7 and 361.65 58.2 m, respectively;p= 0.0004) and ONSASW (1.371 0.035 and 1.52 0.133 mm, respectively;p= 0.011) were statistically significant.
 CONCLUSION:Patients with normal tension glaucoma had significantly higher LCD value with significantly lower LCT and ONSASW values compared to healthy individuals, which is comparable with the results of our pilot study, and confirms the importance of these morphometric criteria in normal tension glaucoma diagnosis verification.