Axial length affects RNFL thickness profiles

Axial length/refractive status affects the peripapillary retinal nerve fibre layer (RNFL) thickness profile in eyes measured by RTVue OCT.

Dr Veysi öner et al., Department of Ophthalmology, Recep Tayyip Erdoğan University Medical School, Rize, Turkey, divided 98 subjects into three groups. The myopic group contained 35 patients, the emmetropic group had 30 patients and the hyperopic group consisted of 33 patients.

The RTVue was used to obtain RNFL thickness measurements for all octametric section parameters. Axial length and spherical equivalent values were also obtained for all subjects.

It was discovered that the RNFL thickness values were thinner in myopic eyes, compared to hyperopic eyes. Average RNFL thickness and RNFL thicknesses of the superotemporal, superonasal, inferotemporal and lower temporal sectors significantly differed between the myopic and emmetropic eyes.

The RNFL thicknesses of the upper temporal and inferonasal sectors were significantly different between hyperopic and emmetropic eyes. Average peripapillary RNFL thickness was negatively correlated with axial length, but this significant difference was eradicated after correction.

For the correct diagnosis of glaucoma the axial length-induced magnification effect must be corrected or the RTVue OCT database should consider axial length.

To read the abstract in the British Journal of Ophthalmology please click here.