Just the cornea from the high poly eyes, as a separate object. Edit: punkduck was kind enough to make an improved material with texture, so I've uploaded it here. The texture is 1024x1024, because that's the minimum file size you can upload, but it's just a transparent square, so you can resize it to be smaller after downloading it. The screenshot has eyes set to "none", just to show the cornea.
CC0 - Creative Commons Zero