I suggest you discuss this issue with an ophthalmologist. Associated with each eye are glands that produce tears throughout the day and night. Tears function to keep the eye clean, lubricated, and have a role in preventing infection. If tears are reduced in terms of quantity or quality, patients experience dry eyes and symptoms such as burning, itching, redness, irritation, difficulty opening or closing the lids, and occasionally changes in vision. Sometimes overnight tears and mucous can accumulate in and around the eye. Tears are composed of water, oil, and mucous. So, when tears dry up, the concentration of water decreases, the relative concentration of oil and mucous increases, and the tears consequently thicken. When tears dry all the way, the residual substances and any trapped debris crystallize into the familiar "sleep" that crusts around the corners of the eye in the mornings. The cause of your brief visual changes in the morning may be a result of drying and thickening of your tears overnight. The brief blurring of your vision in the morning could be a result of dried out thickened tears remaining in your eyes first thing in the morning, before you blink to clear them away. This phenomenon is probably nothing to be concerned about, but the possibility exists that the increased mucous you are experiencing in your eyes in the morning could be a symptom of a disorder or infection of your eye or eyelid. Again, I would recommend that you see an ophthalmologist for an eye examination, because there is no substitute for a complete examination by an eye specialist
to determine the nature of an eye problem.