Character Creator v3.3 introduces Tear Line and Occlusion Mesh to present realistic eyes in a real-time engine. Tear Line enhances eyelid moisture, while Occlusion Mesh adds eyeball shadows. There are dedicated shaders for these eye elements. What’s more, Tear Line and Occlusion Mesh will morph along with different eye shapes, and adapt to any expression.
https://www.reallusion.com/character-creator/character-base.html
Realistic eyes (free upgrade) for Character Creator 3

Eye Shader
The Eye Shader is designed to bring realistic rendering of an eye model. Exposing aesthetic control over each of the biological parts of the eye
Digital Human Shader https://www.reallusion.com/character-creator/digital-human-shader.html