6 Line with eye bulge. Need help!

[Sweet Reef Corals]

I have looked thru many threads and tried some treatments but I feel I need more specific directions to go at this point. I’ve had this 6 line for about 9 weeks. He went thru 6 weeks of hypo salinity QT (unmedicated) before transferring him to my big SPS system. 7’x2’x18” frag tank. A couple weeks after introducing him, I noticed 1 eye starting to bulge behind and at the top of the eyeball. Upon reading about popeye on R2R, lots of threads said it could clear up on its own. So, I decided to give it a few weeks to see if it would clear up. It never did. The bulging bubble actually increased in size, pushing the eyeball downward, as you’ll see in the pics. Since 6 lines like to sleep in a snot bubble I positioned his pvc sleeping bed where I could quickly pull it at night to transfer him to a QT for treatment. I have dosed a little higher than suggested API Erythromycin for 7 days now and the eye looks no better. I started the first of 3 doses of Seachem Kanaplex today. He has never had an issue with the eye. Eats frozen and pellets like a pig and still constantly hunts for pods. No other fish have issues. This is my SPS system so the water quality is impeccable.
1.026
NO3 15
Po4 .03
8.2 Alk
430 Ca
1460 Mg

Please take a look at the pics and give me some advice? I really don’t want him to lose the eye...

 

[Sweet Reef Corals]

Forgot to add the tag #fishmedic

 

[Jay Hemdal]

Forgot to add the tag #fishmedic

It looks like there is a gas bubble along the top of the eye? If so, but Sorry, the fish will likely lose this eye. Injuries to an eye can produce gas, in turn, that pulls on the eye socket. I’ve tried many times to bleed this gas off with a syringe, but it has always returned for me. Erythromycin in a treatment tank can help reduce the chance of infection, but doesn’t really do anything for the gas bubble.
Jay