LearnLens is a modular, LLM-based system that empowers teachers to efficiently provide effective feedback essential for student learning. Specialized in science education, it generates personalized, curriculum-aligned feedback. LearnLens consists of three components: (1) an error-aware assessment module that catches subtle reasoning errors; (2) a curriculum-based generation module that uses structured, topic-linked memory chains instead of traditional similarity-based retrieval to increase relevance and reduce noise; and (3) an educator engagement interface for customization and supervision. LearnLens addresses key challenges in existing systems, delivering scalable, high-quality feedback that empowers both teachers and students.