To be precise, the "Fake Refraction Shell" is essentially a false specular reflection. Its function is to replace the outermost shell of the female eye model in VAM. If I'm not mistaken, that outermost shell is likely meant to provide refraction and corneal convex reflection for the eyes during character rendering. In practice, this shell in VAM mostly produces only a poor, coarse reflection effect. To barely see any result, it often requires enabling VAM's built-in skybox and raising the Specular Intensity parameter. If you don't like it, you can use the "Fake Refraction Shell" instead.
Usage:
1 Use the Fake Refraction Shell parameter in the morph to push the outermost "Loser reflection shell" of the eye into the character's head interior.
2 Equip the Fake Refraction Shell clothing item, and select your preferred effect from the presets. If the layering order is incorrect, it can be adjusted by modifying the clothing shader render queue or by slightly nudging the position in the "Adjustments" tab.
You can get some inspiration for creating those super realistic eyes in the video from my clothing combinations.
Other key Clothing for the eyes in the video,
VL_13.Lacrimal_gland_v2.2
Skynet.Eyes_shadow_Reflection.5
Photorealistic eye
Thank you to every talented creator.