RT Journal Article SR Electronic A1 Lestak, Jan A1 Fus, Martin A1 Pitrova, Sarka T1 Peripapillary retinal nerve fiber layer following vessel density correction at different IOP values JF Biomedical papers YR 2025 VO 169 IS 2 SP 140 OP 143 DO 10.5507/bp.2024.001 UL https://biomed.papers.upol.cz/artkey/bio-202502-0009.php AB Purpose. The aim of this study was to define the thickness of the retinal nerve fiber layer (RNFL) in the peripapillary region of the retina after adjusting for the effect of vessel density (VD) in patients with pathological intraocular pressure (IOP). Patients and Methods. 69 patients (122 eyes) with IOP >21 mmHg (range 21-36 mmHg, mean 23.65±2.70 mmHg). 32 were men (average age 55±13 years) and 37 were women (average age 52±14 years). IOP was measured using the Ocular Response Analyser (ORA). VD and RNFL were measured peripapillary by OCT (Avanti RTVue XR) in eight segments: Inferior Temporal - IT (1); Temporal Inferior - TI (2); Temporal Superior - TS (3); Superior Temporal - ST (4); Superior Nasal - SN (5); Nasal Superior - NS (6); Nasal Inferior - NI (7) and Inferior Nasal - IN (8). The VD value was subtracted from the total RNFL value. Results. A corrected value for the RNFLc nerve fiber layer thickness (RNFLc) was introduced to account for VD across the RNFL volume in each segment. Person's correlation coefficient (r) was used to assess the correlation between IOP and RNFLc. The strongest correlations in RNFLc were in segments 5 (r=-0.32, P=0.002) and 8 (r=-0.21, P=0.037). Conclusion: The greatest changes in RNFLc (RNFL minus VD) were in eyes with pathological IOP in segments 5 and 8, the location of the retinal ganglion cell magnocellular fibers. That is, when the thickness of the nerve fiber layer was reduced by correcting for vessel density, there was a significant correlation in segments 5 (r =-0.32, P<0.05) and 8 (r =-0.21, P<0.05) with intraocular pressure. The results suggest use of a corrected RNFL from VD value as more appropriate for detecting early changes in glaucoma.