Every licensed doctor took a rotation in Ophthalmology, regardless of their eventual specialty, and emergency room physicians in particular are trained in a number of skills that other specialists are not. The fact that your husband's vision is fine and suffered no damage is in itself proof that he knew enough to take care of the immediate problem.
However, if the ER physician had called the Ophthalmologist to come and remove the first particle, the Ophthalmologist would have made more money. There is not a whisper of doubt in my mind that this is the real source of the Ophthalmologist's issue.
It is a hard fact of law that you cannot sue for something that didn't happen. Your husband has suffered no damages. There is no legal action for you to take.
However, if you would prefer to spend your money looking for a lawyer to take on a case of of professional jealousy, it's your money to spend.