Abstract
Purpose :
To evaluate morphological and morphometric findings of optic disc and fovea related to axial length (AL) in healthy eyes.
Methods :
One hundred-six eyes of 56 subjects between June and November 2016 were recruited. Exclusion criteria were: best corrected visual acuity less than 0.0 LogMar, presence of ocular pathology, previous ocular trauma or surgery. Demographic and clinical data were: age, gender, intraocular pressure (mmHg), spherical equivalent (SE diopters D), AL (millimeters mm). Spectral Domain Optical Coherence Tomography (SD-OCT) morphometric parameters were: optic disc–fovea distance (microns μ), retinal nerve fiber layer (RNFL) thickness, optic disc diameter (μ), optic disc-fovea angle, defined as angle between the horizontal line-scan passing through the fovea and the line-scan passing through the center of the optic disc and the fovea. Tomographic morphological parameter was the foveal position, defined on the basis of tomographic foveal position relative to the profile of retinal pigment epithelium and Bruch’s membrane (EPR-Bruch’s profile) viewed in horizontal (H-scan) and vertical (V-scan) scans. Four patterns respectively for H-scan and V-scan were described: ‘central pattern’, characterized by the fovea centered on the concavity of EPR-Bruch’s profile, viewed respectively in H-scan and V-scan; ‘sloped pattern’, characterized by the fovea on the slope of nasal or temporal wall of EPR-Bruch’s profile viewed in H-scan or on the slope of superior or inferior wall of EPR-Bruch’s profile viewed in V-scan; ‘straight pattern’ characterized by the fovea on a straight plane, parallel to EPR-Bruch’s profile, viewed in H-scan and V-scan. (see figure)
Results :
Mean age was 47.72±17.93 years; mean SE was -1.89±3.21 D, mean AL was 24.69±1.62 mm. A strong correlation between AL and optic disc-fovea distance was demonstrated (p 0.014). Linear regression showed that horizontal optic disc diameter (p 0.003) and RNFL thickness (p 0.00) decreased in longer eyes.
Central and straight foveal pattern were the most prevalent patterns viewed in horizontal scan. Central foveal pattern was associated with longer eyes compared to straight pattern (p 0.01).
Conclusions :
AL affected RNFL thickness, optic disc size and tomographic foveal profile pattern in healthy eyes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.