Trans-Lamina Cribrosa Pressure Difference and Open-Angle Glaucoma. The Central India Eye and Medical Study

Purpose To assess associations of the trans-lamina cribrosa pressure difference (TLCPD) with glaucomatous optic neuropathy. Methods The population-based Central India Eye and Medical Study included 4711 subjects. Based on a previous study with lumbar cerebrospinal fluid pressure (CSFP) measurements, CSFP was calculated as CSFP[mmHg] = 0.44 Body Mass Index[kg/m2]+0.16 Diastolic Blood Pressure[mmHg]−0.18×Age[Years] −1.91. TLCPD was IOP–CSFP. Results Mean TLCPD was 3.64±4.25 mm Hg in the non-glaucomatous population and 9.65±8.17 mmHg in the glaucomatous group. In multivariate analysis, TLCPD was associated with older age ( P <0.001; standardized coefficient beta:0.53; regression coefficient B:0.18; 95% confidence interval (CI):0.17, 0.18), lower body mass index ( P <0.001; beta: −0.28; B: −0.36; 95%CI: −0.38, −0.31), lower diastolic blood pressure ( P <0.001; beta: −0.31; B: −0.12; 95%CI: −0.13, −0.11), higher pulse ( P <0.001; beta:0.05; B:0.02; 95%CI:0.01,0.2), lower body height ( P  = 0.02; beta: −0.02; B: −0.01; 95%CI: −0.02,0.00), higher educational level ( P <0.001; beta:0.04; B:0.15; 95%CI:0.09,0.22), higher cholesterol blood concentrations ( P <0.001; beta:0.04; B:0.01; 95%CI:0.01,0.01), longer axial length ( P  = 0.006; beta:0.03; B:0.14; 95%CI:0.04,0.24), thicker central cornea ( P <0.001; beta:0.15; B:0.02; 95%CI:0.02,0.02), higher corneal refractive power ( P <0.001; beta:0.07; B:0.18; 95%CI:0.13,0.23) and presence of glaucomatous optic neuropathy ( P <0.001; beta:0.11; B:3.43; 95%CI:2.96,3.99). Differences between glaucomatous subjects and non-glaucomatous subjects in CSFP were more pronounced for open-angle glaucoma (OAG) than for angle-closure glaucoma (ACG) (3.0 mmHg versus 1.8 mmHg), while differences between glaucomatous subjects and non-glaucomatous subjects in IOP were higher for ACG than for OAG (8.5 mmHg versus 3.0 mmHg). Presence of OAG was significantly associated with TLCPD ( P <0.001; OR:1.24; 95%CI:1.19,1.29) but not with IOP ( P  = 0.08; OR:0.96; 95%CI:0.91,1.00). Prevalence of ACG was significantly associated with IOP ( P  = 0.04; OR:1.19; 95%CI:1.01,1.40) but not with TLCPD ( P  = 0.92). Conclusions In OAG, but not in ACG, calculated TLCPD versus IOP showed a better association with glaucoma presence and amount of glaucomatous optic neuropathy. It supports the notion of a potential role of low CSFP in the pathogenesis of open-angle glaucoma.