The best way I found to make a v/quick iris in Photoshop 4/5 is to create a basic circle, fill it with any basic eye colour you want, air brush in a little depth w/black around the edges. Then add guassian noise twice, first colour, then monochromatic (B/W) noise @ a slightly different amount setting. Now apply a fair amount of radial blur/zoom filter @ medium quality setting to your noisy circle and voila' a funky iris type texture. Duplicate the layer and add a pupil and apply a very slight amount of Radial/zoom blur to the layer to merge the the pupil with the iris. Air brush in some high lights, shade and add a little bit more noise to add some more variation to the texture. For an intense highlight/reflection create a black layer above your iris, apply a lens flare to it and turn its layer options from normal to screen, so all the black becomes invisible and you have a cool flare type highlight. Erase the parts of the flare you dont want from that layer and you should be looking at a complete and convincing hand drawn iris.