Please post your water parameters, ammonia, nitrite, nitrate, Ph and hardness if available. Most eye infections or Pop eye is caused by gram positive bacteria. Maracyn or API Erythromycin is the correct med for this in most instances. Your water perameters will dictate wheather or not this will be an effective cure so please provide them before starting treatment.
Erythromycin is hard on nitrifying bacteria at a PH over about 7.2 so keep an eye on you BB during treatment as BB is also gram positive. In well established aquariums the BB usually comes back pretty fast but new tank will not so either use a hispital or have some seeded filter material ready to use after treatment.