I had problems with the eyes when I first started using Reality3 and I always use real reflection, not baked in.  Thankfully I was given this advice -

In Reallity I set the Cornea to arch glass, the diffuse and specular color to 255 255 255 and make sure the thin film thickness and the thin film IOR are at 0. with no bump map. The iris and pupil set the specular to 20 20 20 20 with glossiness to 9200 up to 9600.

Above is what the result, and I can adjust the size and position of the hightlight by adjusting the meshlight.

 

 

 

I use Poser 13 on Windows 11 - For Scene set up I use a Geekcom A5 -  Ryzen 9 5900HX, with 64 gig ram and 3 TB  storage, mini PC with final rendering done on normal sized desktop using an AMD Ryzen Threadipper 1950X CPU, Corsair Hydro H100i CPU cooler, 3XS EVGA GTX 1080i SC with 11g Ram, 4 X 16gig Corsair DDR4 Ram and a Corsair RM 100 PSU .   The desktop is in a remote location with rendering done via Queue Manager which gives me a clearer desktop and quieter computer room.