Its not hard to get that glint without postwork or pre done reflections that may not match your scene. If you have the HSS or the daz shaders from the old freepository. Both of them add a second specular setting that makes it easy to get glints. To use the secondary spec to get the highlights  the settings are white with spec2 at 62%, spec2 roughness 46.6 and spec2 sharpness 97.4 on the eye surface.

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