It's in the Spot Healing pop-out, but I never use it. There is an option in Camera RAW, but prefer to use a Hue/Saturation layer. Select both pupils with the eliptical marquue tool > Open the H/S layer, and adjust hue, sat, and lightness if required.
or
Open the H/S layer with no selection in place, and use the RGB drop-down and select the Reds. Then adjust hue, sat, lightness. Invert the layer mask, and paint back in with a soft white brush.