Yella is a 5 yr old lab mix. He is a realy big dog (120 lbs) with a super personality (he is a big baby).About 3 yrs ago his wheight was up to 140lbs he was a little lithargic and he began to develop a white circle around the outside of the iris of his left eye. My vet tried a lot of different meds to no avail and I finally brought Yella to an opthamologist who tried some meds and finally suggested a blood workup. From this Yella was diagnosed with thyroid problems and given meds which seemed to work.he lost weight and became a lot more active and the ring around his iris became less pronounced.
Lately however ,although he is still getting his thyroid meds, the ring in his iris is becoming more pronounced and no one seems to know what it is or what is causing it.ANY SUGGESTIONS!!!!