STB-Net: a Siamese architecture-based reconstruction-segmentation network for ocular surface image segmentation.

Background: Eyelid morphological parameters are crucial for quantitatively assessing eyelid morphology and diagnosing related disorders. However, achieving precise and automated measurement of these parameters remains a challenge. This study aims to develop an automated segmentation model for ocular surface images to accurately segment key anatomical structures and compute critical eyelid metrics. Methods: We propose STB-Net, a novel segmentation model tailored for ocular surface imagery. The baseline model, TB-Net, enhances the TransUNet architecture by integrating a Bottom-up Local Attention Modulation (BLAM) module into its decoder, effectively encoding fine-grained features from shallow layers into high-level semantics. The final STB-Net framework integrates TB-Net with an SRSNetwork. In this setup, a TB-Net is first employed as a reconstruction model to learn complex semantic information. Subsequently, its encoder serves as a dynamic convolution module to generate adaptive parameters for a second, segmentation-oriented TB-Net, thereby boosting segmentation performance through augmented reconstruction-task training. The model automatically computes left, central, and right palpebral fissure heights, palpebral fissure width, and area based on the segmentation results. Results: Experimental evaluation on a local dataset demonstrated the model's high efficacy. For palpebral fissure segmentation, the model achieved a Dice score of 0.9875, Global Accuracy (GA) of 0.9955, and Intersection-over-Union (IoU) of 0.9767. Corneal segmentation performance was equally strong, attaining a Dice of 0.9891, GA of 0.9978, and IoU of 0.9790. Conclusions: The proposed STB-Net model provides a robust and effective solution for the automated segmentation of ocular surface structures and the precise quantification of eyelid morphological parameters. It holds significant promise for enhancing the objectivity and efficiency of clinical diagnoses of eyelid disorders.