Abstract
Purpose: :
To investigate the influence of axial length and refractive error on the tomographic profile of peripapillary retinal nerve fiber layer thickness (RNFL) in healthy eyes
Methods: :
Four hundred ninety eight eyes of 249 healthy young male volunteers were enrolled to this cross-sectional study. All subjects underwent ophthalmologic examinations including RNFL thickness analysis with spectral domain optical coherence tomography (OCT), refraction and axial length measurement. From the RNFL thickness result of OCT scan, the angular location of maximal superotemporal RNFL thickness point from a reference line, which was drawn horizontally through the center of the scan circle, was calculated. With the same method, the angular location of maximal inferotemporal RNFL thickness point was calculated. The relationship of axial length and spherical equivalent (SE) with angular locations of these maximal RNFL thickness points was studied.
Results: :
The mean ± SD of axial length and SE was 24.71 ± 1.24 mm and -2.46 ± 2.36 diopter, respectively. The mean ± SD of angular location of the highest superotemporal and inferotemporal RNFL points was 77.55 ± 11.01 degree and 316.99 ± 17.10 degree, respectively. As the SE decreased every 1 diopter, the angle of highest thickness point of superotemporal and inferotemporal RNFL hump measured lower by 1.58 degree (P < 0.05) and 1.10 degree (P < 0.05), respectively. As the axial length increased every 1 mm, the angle of highest thickness point of superotemporal and inferotemporal RNFL hump measured lower by 2.38 degree (P < 0.05) and 2.11 degree (P < 0.05), respectively.
Conclusions: :
Peripapillary maximal thickness points of both superotemporal and inferotemporal RNFL were located closer to the fovea in eyes with lower SE and longer axial length. These variables may need to be taken into account when constructing internal normative database of Stratus OCT and evaluating patients for diagnosis of glaucoma based on this device.
Keywords: imaging/image analysis: clinical • myopia • anatomy