Multiscale Attention Unet: An Innovative Approach for Segmentation of Optic Disc and Optic Cup in Early Detection of Retinopathy.

Objective: To develop an accurate optic disc (OD) and optic cup (OC) segmentation model for early glaucoma detection and differentiation from high myopia through precise cup-to-disc ratio (CDR) calculation. Timely intervention and differential diagnosis between high myopia and glaucoma are crucial for disease progression and treatment effectiveness. Design: Retrospective cross-sectional study of 3 independent ophthalmic data sets. Subjects: 2814 fundus images from 3 public data sets:ORIGA (650 images); REFUGE (1200 images); G1020 (964 images). Methods: Proposed Multiscale Attention Unet (MAUnet) integrates: (1) Incorporating multiscale convolutional (3 × 3 and 5 × 5 kernels) for hierarchical feature extraction. (2) Efficient Channel Attention modules integrate the Efficient Channel Attention Network into the Unet architecture to enhance region-of-interest localization. (3) Hybrid loss function combining Dice loss (macro-structures) and cross-entropy loss (microdetails, λ = 0.5) to solve class imbalance and boundary ambiguity. Main Outcome Measures: Dice Similarity Coefficient (DSC) for OD/OC; Intersection over Union; Absolute CDR error; Boundary F1-score. Results: Multiscale Attention Unet demonstrated superior segmentation performance across all benchmark data sets. On the ORIGA data set, it achieved DSCs of 0.958 for OD and 0.912 for OC, with an absolute CDR error of 0.038. For the REFUGE data set, the model attained DSC values of 0.972 (OD) and 0.931 (OC), alongside a CDR error of 0.026. Evaluation on the G1020 data set yielded DSCs of 0.963 (OD) and 0.906 (OC), with a CDR error of 0.041. Crucially, MAUnet significantly outperformed comparator models in OC segmentation, evidenced by a mean Boundary F1-score of 0.887 versus the comparator range of 0.812 to 0.852 ( Conclusions: The proposed MAUnet model shows superior performance in OD and OC segmentation, proving to be a clinically reliable tool for early glaucoma detection and monitoring. Its multiscale attention mechanism and balanced loss function enable accurate segmentation, particularly for challenging edge and detail detection, improving glaucoma screening and early diagnosis across diverse populations. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.