A film of tears over the front of the eye is the first thing that light passes through in order to start the focusing process. Lack of that film off and on during the day can cause intermittent blurred vision.
Real estate agent Mark Cohen paid a visit to the eye doctor.
"I just had a pretty persistent irritation, but almost like a scratchiness - almost like you had little grains of sand in your eye," said Cohen.
The diagnosis? Dry eyes. Staring at monitors all day reduces normal blinking, and bright lights and blowing air conditioners also can cause symptoms of burning. It may feel as if an eyelash is caught under the eyelid. Another symptom that comes and goes is blurred vision.
"After five or six hours in the office staring at a computer screen, with the lights, then they notice it," said Elizabeth Schnipper, O.D. at VRM Consultants of New York.
Women are more at risk than men, especially around menopause. The cure is simple - many times, it is over-the-counter artificial tears.
For some patients, rather than using artificial tears, a simple procedure allows a patient's own tears to do the job.
Julie Ho was having off-and-on blurred vision in one eye. One doctor thought it was nerve damage.
"I was concerned that it was serious but it turned out it was just dry eye," said Ho.
Ho is having a procedure today that will plug the drainage of her own tears so they will build up to normal - kind of like plugging your sink or tub. However, if you use drops for dry eyes, know when to see the doctor.
"If dry eyes persist, it is worth seeing a eye care professional to see if there are other solutions or an underlying disorder that needs to be treated," warns Dr. Mark Fromer of Fromer Eye Centers.
These disorders include serious issues such as thyroid disease, arthritis or illnesses that cause inflammation of the eyes. Another simple protection is to wear sunglasses in order to keep wind and particles from getting in your eyes. If standard artificial tears cause irritation, it may be helpful to try some that contain no preservatives.