Interocular Asymmetry of Visual Field Loss, Intraocular Pressure and Corneal Parameters in Primary Open-angle Glaucoma.

OBJECTIVES To assess the association between the corneal biomechanical parameters and visual field (VF) loss in patients with asymmetric primary open-angle glaucoma (POAG). METHODS A total of 89 POAG patients (50 males, 56.2%) with asymmetric VF loss, aged 65.2 ± 13.3 years old, were enrolled in this study. Asymmetric VF loss was defined as an interocular difference of the global index mean deviation (MD) >2dB. Intraocular pressure (IOP), central corneal thickness (CCT) and corneal biomechanical parameters such as maximum amplitude at the apex of highest concavity (Def ampl HC) were measured. The worse eye was defined as the eye with a smaller MD. RESULTS The worse eyes had lower MD (-11.9 ± 6.7 dB vs. -5.3 ± 5.0 dB; P<0.001) and higher IOP (14.6 ± 3.3 vs.13.9 ± 2.6 mmHg, P=0.04) than the better eyes. There was no significant difference between the two groups for CCT. The interocular difference of MD (IDMD) was negatively correlated with the interocular difference of IOP (r=-0.22, P=0.04), while positively correlated with the interocular difference of Def ampl HC (r=0.27, P=0.01). In patients with moderate asymmetric VF loss (IDMD ≥6 dB), the Def ampl HC of the worse eyes group (1.07 ± 0.12 mm) were significantly lower than the better eyes group (1.10 ± 0.11 mm, p=0.02). CONCLUSION Asymmetric POAG was associated with asymmetry in IOP and corneal biomechanical parameters but not in CCT. Lower deflection amplitude and higher IOP was found in eyes with more severe visual field damage in POAG patients.