Ophthalmic diseases pose a significant global health challenge, yet traditional diagnosis methods and existing single-eye deep learning approaches often fail to account for binocular pathological correlations. To address this, we propose DMS-Net, a dual-modal multi-scale Siamese network for binocular fundus image classification. Our framework leverages weight-shared Siamese ResNet-152 backbones to extract deep semantic features from paired fundus images. To tackle challenges such as lesion boundary ambiguity and scattered pathological distributions, we introduce a Multi-Scale Context-Aware Module (MSCAM) that integrates adaptive pooling and attention mechanisms for multi-resolution feature aggregation. Additionally, a Dual-Modal Feature Fusion (DMFF) module enhances cross-modal interaction through spatial-semantic recalibration and bidirectional attention, effectively combining global context and local edge features. Evaluated on the ODIR-5K dataset, DMS-Net achieves state-of-the-art performance with 80.5% accuracy, 86.1% recall, and 83.8% Cohen's kappa, demonstrating superior capability in detecting symmetric pathologies and advancing clinical decision-making for ocular diseases.