My husband recently has experienced a type of tiling or ripple effect with his vision every now and then, lasting maybe 3 to 5 minutes per episode. Can you give a cause or reason why this may be happening? He takes 1 drop of Lumingan every night per doctors order because of what they said was pressure on the eyes that can lead to Glaucoma. We realize this is an educated guess without seeing him yet, but would appreciate your response on possible causes, thank you!