You can change the colour of the eyes individually as shown below:
Select the Material tab in the Modify panel.
Scroll down the list and, for the right eye select CC_Base_Eye > Std_Cornea_R > Digital_Human Eye:
75% of original size (was 673x19) - Click to enlarge
Next, with the Base Color selected in the Texture Settings click on the Adjust Color icon:
75% of original size (was 673x19) - Click to enlarge
In the Adjust Color panel you can now make any changes that you wish.
75% of original size (was 673x19) - Click to enlarge
For the left eye select the Std_Cornea_L material.
Gerry
System: Win 10 Pro (21H2), Asus X99-E WS, CPU i7-5930K -3,5 GHz, 32 GB DDR4 2666-16 RAM, NVidia GTX 1080 Ti GPU - 11 GB VRAM(Driver Studio-536.99), Samsung 850 Pro 512 GB SSD, 6 TB HD storage.