ASSOCIATION OF ESTIMATED TRANS LAMINA CRIBROSA PRESSURE AND OCULAR PERFUSION PRESSURE IN PATIENTS WITH GLAUCOMA

Abstract

Background: Glaucoma is a multifactorial optic neuropathy characterized by progressive retinal ganglion cell loss and visual field defects. While elevated IOP (Intraocular Pressure) is a major risk factor, other pressure-related factors such as TLCP (Trans Lamina Cribrosa Pressure) and OPP (Ocular Perfusion Pressure) may contribute to disease pathogenesis. TLCP represents the difference between IOP and CSFP (Cerebrospinal Fluid Pressure), whereas OPP reflects the relationship between systemic blood pressure and IOP. This study evaluated the association of glaucoma with estimated TLCP and OPP. Methods: A hospital-based cross-sectional study was conducted in the Department of Ophthalmology of a tertiary care teaching hospital from October 2019 to June 2021. Sixty diagnosed cases of primary glaucoma satisfying the inclusion criteria were enrolled. All participants underwent a comprehensive ophthalmic evaluation, including visual acuity assessment, slit-lamp examination, gonioscopy, fundus evaluation, visual field analysis, and IOP measurement using Goldmann applanation tonometry. Blood pressure and BMI (Body Mass Index) were recorded to estimate CSFP, TLCP, and OPP using validated formulas. Statistical analysis was performed using chi-square test, Student’s t-test, and ANOVA. Results: The mean age of the study population was 49.6 ± 10.95 years, with females accounting for 55% of cases. POAG (Primary Open-Angle Glaucoma) constituted 67% of cases, NTG (Normal-Tension Glaucoma) 18%, and PACD (Primary Angle-Closure Disease) 15%. The mean IOP was 24.67 ± 5.46 mmHg, and 70% of patients had IOP >21 mmHg. The mean OPP was 38.80 ± 8.82 mmHg, with no significant correlation between OPP and IOP. Mean TLCP was 11.7 ± 6.51 mmHg and was significantly elevated compared to normal values. A strong positive association was observed between IOP and TLCP (p<0.0001), while TLCP demonstrated an inverse relationship with OPP. Conclusion: Estimated TLCP showed a significant positive association with glaucoma and increased with rising IOP. OPP demonstrated an inverse relationship with TLCP, but its association with glaucoma was less clear. TLCP may serve as a more reliable pressure-related factor in glaucoma assessment than OPP.