It is impossible to diagnose a “white magnesium flash that start near theconjunctiva then circles the eye, explodes and goes away” without seeing it in a visual examination. Macular degeneration is a disorder of the yellow plaque (“macula lutea”) of the retina. Macular degeneration has nothing to do with any type of conjunctive disorder. Conjunctiva is a part of the outer eye layer and macula is part of the retina (inner eye layer). Nonetheless, you can consult an ophthalmologist about your problem to seeks a diagnosis and advice.