Need help with eyes

I'm new to Daz and have been having issues with the eyes of my rendered characters. I have been using Victoria 8 and Genesis 8 female and each time I render I get grainy eyes even though the rest of the image comes out fine. I had simply been using the preset "Victoria 8 eyes 01". I tried paying around with some of the settings for the sclera but nothing fixed the issue. I then purchased the Project EYEray - Next Gen and Merchant Resource for Genesis 8. But when I selected the sclera I wanted to use, the eyes went black even after adding in the pupils. I've managed to play aorund with them a bit and get them to a tan color so I can at least see the pupil, but I feel like I'm totally missing an easy step to get the preset to work. Can anyone direct me to a video or instructions on how to manipulate this so that I'm not feeling like it's a waste of money to buy presets?
Thanks!
Comments
You could try increasing the Render Quality setting or the Convergence Ratio in Render Settings - the trouble being that the eyes are about the last area to finish converging, and they are usually small enough to be in the 5% that isn't converged. Another option would be to switch to the Spot Render tool, in th Tool Settings pane make sure it iss et to render to a new window (so that it will be the same size as the main render), and drag out a rectangle over the eyes (or over one eye and then the other), saving each and placing them on top of the full render to replace the eye sections.
I should add that the black eyes aren't happening just when rendering. When I'm actually working on the model, the eyes are black.