The relationship between retinal nerve fibre layer thickness profiles and CorvisST tonometry measured biomechanical properties in young healthy subjects

We previously reported that a shallow circumpapillary retinal nerve fiber layer (cpRNFL) peak angle as measured by optical coherence tomography (OCT) suggests the temporal retina is stretched around the optic disc from the papillo-macular bundle (Yamashita T et al. Investigative Ophthalmol Vis Sci 2013). The purpose of the current study was to investigate the relationship between CorvisST tonometry (CST) corneal measurements, axial length (AL) and the change in OCT-measured cpRNFL peak angle, in young healthy subjects. OCT and CST measurements were carried out in 97 eyes of 97 young healthy volunteers. The relationship between cpRNFL peak angle and 12 CST parameters, adjusted for AL, was investigated using linear modelling. The mean ± standard deviation cpRNFL peak angle of the 97 healthy volunteers was 130.6 ± 25.4 (range: 77.8 to 207.0) degrees. The optimal linear model to explain cpRNFL peak angle (chosen from 2(16) different models) included three CST variables related to the speed and size of energy absorption (namely, A1 time, A1 length and A2 time), in addition to AL. In eyes with longer AL and shorter energy absorption in CST measurement, temporal retina is stretched around the optic disc from the papillo-macular bundle, as suggested by a shallow cpRNFL peak angle.