Retinal nerve fiber layer thickness and central corneal thickness in ocular hypertensive patients and healthy subjects

Abstract

Abstract Purpose To establish the correlation between central corneal thickness (CCT) and retinal nerve fiber layer (RNFL) thickness in ocular hypertensive patients and healthy subjects. Methods We prospectively collected charts of healthy subjects and ocular hypertensive (OHT) patients in one academic center between 2007 and 2008. OHT patients were defined by two measurements of intraocular pressure superior to 21mmHg without treatment, open angle in gonioscopy, normal appearing optic nerve head and normal visual field test Standard Automated Perimetry (SAP SITA) and Frequency Doubling Technique (FDT). Every patient underwent a standard clinical examination including optic nerve head examination, intraocular pressure, CCT measurement by ultrasonic (US) and anterior segment OCT pachymetry, visual field testing (SAP and FDT), RNFL thickness by scanning laser polarimetry (GDX‐VCC) and optical coherence tomography (OCT). Results Eighty healthy subjects and 60 OHT patients were included. A correlation between US CCT and OCT CCT was found in both groups (r2=0.85 and r2= 0.87, p<0.001). There was no significant difference (p>0.15) in GDX‐VCC and OCT RNFL thickness in both groups. In controls there was no correlation of any RNFL thickness measurement with the CCT. In OHT patients, the US CCT was weakly correlated with the average TSNIT evaluated by GDX‐VCC (r2= 0.04, p<0.02). Conclusion This study did not show any relevant correlation between the RNFL thickness evaluated by GDX‐VCC and the US CCT in healthy individuals and in OHT patients with a normal FDT.