Dryness of the eyes and/or mouth is common, especially among persons as they age; however, age alone is frequently NOT the only reason and other causes are often quite treatable or reversible.
Fortunately, serious or dangerous causes of dryness of the eyes and mouth are rare.
If you have significant discomfort in the eyes, especially when you blink, you should see you eye doctor right away.
Treatment for dry eyes usually starts with simple things: a humidifier to keep the air moist, lubricating eye drops and an evaluation to determine the cause (For severely dry eyes, small, plastic plugs can be inserted near the eyelid to prevent tears from draining away as quickly and cause more moisture to remain on the eye surface.).
Treatment for dry mouth usually starts with simple things as well: searching for a cause (such as certain medications), frequent sips of water or ice, and a fluoride toothpaste and rinse to prevent cavities (which are more common in people with significantly reduced saliva).