Interpretable Diabetic Retinopathy Classification Using Hybrid ConvNeXt–MLP-Mixer and ConvNeXt–PoolFormer Architectures
Year: 2026
Type: article
Abstract: Diabetic retinopathy (DR) severity grading from retinal fundus images is challenging because retinal abnormalities vary in size, distribution, and severity. This study evaluates two hybrid architectures, ConvNeXt–MLP-Mixer and ConvNeXt–PoolFormer, for five-class DR classification by combining convolutional feature extraction with global feature mixing. Experiments used the APTOS 2019 Blindness Detection dataset from Kaggle. After exact-duplicate filtering, 3,596 images remained: 2,502 for training, 544 for validation, and 550 for held-out testing. The imbalanced test set comprised five DR severity classes. The proposed models were compared with EfficientNet, Vision Transformer, ConvNeXt, MLP-Mixer, and PoolFormer using accuracy, macro- and weighted F1-scores, and macro- and weighted-average one-versus-rest (OvR) ROC-AUC. ConvNeXt–PoolFormer achieved 82.7% test accuracy and 82.7% weighted F1-score, while ConvNeXt–MLP-Mixer achieved 82.4% accuracy and 82.5% weighted F1-score, with the latter obtaining the highest macro F1-score of 67.5%. Moderate DR showed the clearest class-specific improvement, whereas Severe and Proliferative DR remained difficult to classify. Layer-wise Relevance Propagation (LRP) and Grad-CAM generated post-hoc visual explanation maps for representative predictions. These visualizations were treated as exploratory because they were not independently validated using lesion-level annotations or by clinical experts, including ophthalmologists.
Institution: Diponegoro University
Language: English
Topic: Retinal Imaging and Analysis
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $32
OpenAlex ID: W7223351273