An optical device for measuring corneal, includes a light source module, a first optical module, a second optical module, a light beam splitter and image analysis unit. The second optical module includes a reference mirror. The light beam provided by the light source module is split by the light beam splitter, and respectively enters the first and the second optical modules. A portion of the light beam is transmitted through the light beam splitter, the first optical module to the corneal, and is reflected by the corneal and formed into a first reflective light. The other portion of the light beam then is transmitted through the light beam splitter, the second optical module to the reference mirror, and is reflected by the reference mirror and formed into a second reflective light. The first and the second light beams could be transmitted to the light beam splitter and enter the image analysis unit. The reference mirror could move along the first direction. While the first and the second light beams interfere, an optical path difference is calculated and detected.一種用於角膜量測的光學影像裝置,包括光源模組、第一光學元件組、第二光學元件組、分光器以及影像分析單元。第二光學元件組包括參考鏡。透過分光器光源模組提供的光線分別傳遞至第一以及第二光學元件組。光源模組的光線係經由分光器、第一光學元件組傳遞至角膜後形成第一光線。光源模組的光線經由分光器傳遞至第二光學元件組的參考鏡後形成第二光線,第一及第二光線依序傳遞至分光器以及影像分析單元。參考鏡可沿第一方向移動,當第一光線與第二光線產生干涉,得以擷取一相對的光學路徑長。2‧‧‧光學影像裝置20‧‧‧光源模組22‧‧‧第一光學元件組221、242‧‧‧透鏡222‧‧‧反射鏡24‧‧‧第二光學元件組241‧‧‧參考鏡26‧‧‧分光器28‧‧‧影像分析單元3‧‧‧角膜X‧‧‧第一方向Y‧‧‧第二方向