Hi,
Yellowish eyes occur due to jaundice.
Have a liver function test done for evaluation.
Depending on the LFT results further tests and treatment can be planned.
I'm a nurse, and I would first wonder if you have had your liver tested to make sure your liver enzymes are within normal limits or ever had some form of hepatitis or are on meds that can decrease liver function after time. This can cause yellowing of the whites of the eyes and is known as "Jaundice."
Your second question, "How can I have as they would say Purley Whites for eyes" I'm not sure there is a cosmetic treatment to make them whiter, you would have to do some research on that one. But eating healthy and getting a good nights sleep every night will help significantly. When people say "Pearly Whites" they are referring to teeth, not the whites of the eyes. Hope this helps a little :)