Fundus Refraction Offset as an Individualized Myopia Biomarker

Area of Science:

• Ophthalmology
• Medical Imaging
• Computational Biology

Background:

• Standard metrics like spherical equivalent refraction (SER) and axial length (AL) do not fully capture individual posterior segment anatomy.
• A novel fundus-level metric is needed to assess anatomical variations in ametropia.

Purpose of the Study:

• To introduce fundus refraction offset (FRO) as a novel fundus-level metric.
• To investigate the association between FRO and ocular parameters obtained via optical coherence tomography (OCT).

Main Methods:

• A deep learning model was trained on fundus photographs from the UK Biobank to predict SER.
• The model derived FRO by comparing predicted SER to actual SER.
• Associations between FRO and OCT-derived parameters (macular thickness, choroidal area, choroidal vascularity index) were analyzed in UK Biobank and Caledonian cohort datasets.

Main Results:

• A more negative FRO was significantly associated with lower macular thickness in both internal and external datasets.
• The choroidal vascularity index (CVI) decreased as FRO became more negative.
• FRO effectively captured individual-level anatomical variations not reflected by SER or AL.

Conclusions:

• FRO quantifies the mismatch between refractive error and ocular anatomy.
• This metric holds potential for personalized risk prediction of myopia and its complications.
• FRO may enhance our understanding of nonpathological variations in fundus appearance.