In high-end chip manufacturing, extreme ultraviolet (EUV) lithography has become indispensable for large-scale integrated circuit production, and is fundamental to the continued progress of future processing technologies. The laser-produced plasma (LPP)-EUV light source is a critical subsystem of EUV lithography machines, among which the liquid tin droplet generator is a key component. This generator must stably and continuously produce tin droplets of uniform size and spacing at a specific frequency to achieve a stable and efficient conversion efficiency (CE) under laser irradiation. Therefore, measurement and detection systems targeting tin droplet generation are essential for studying the droplet formation mechanism and interaction between droplets and lasers. Such systems play a crucial role in the development of LPP-EUV light sources by improving the droplet quality, increasing the optical CE, reducing debris generation, and ensuring source stability. Optical measurement, as the primary method of measurement and detection, lacks a systematic summary of its application in this field. This paper reviews the core metrics, key requirements, and current technological developments in the optical measurement and detection of tin droplet generators in EUV light sources. It provides a detailed analysis of the characteristics of mainstream measurement techniques and system solutions, which can serve as a technical reference and support for the development of tin droplet generation systems and research on LPP-EUV light sources.