Welcome to Yorkie Talk. There are many potential causes of eye drainage and staining. Here is a link to an article about it:
http://www.yorkietalk.com/forums/die...ar-stains.html
At 7 months, teething could be contributing to Roo's drainage.
Is there a reason the vet prescribed ointments and drops? I've only heard of this if there is a medical problem, like an injury or dry eye. Some Yorkies do not produce enough tears to keep the eye moist, and some are born missing the glands for tear production. These problems can easily be diagnosed by a good vet or specialist.
My boys' eye gunk is usually from environmental allergens, worse during the spring and fall. Sometimes it is from hair in the eye. We clean daily and use a flea comb with closely spaced teeth to comb the corners of the eyes.
I also like Tropiclean Spa facial cleanser. Great for tear stains and grubby beards, but gentle on the eyes.
Sometimes a food change will help improve eye drainage.
I know people who have had success with Angel Eyes, but it does contain an antibiotic that some sources say is not good for long term use.
I think you would be better off trying to pinpoint the underlying cause of excessive eye drainage.