• Can you explain why I have halos and blurry vision in the morning?


    Question:

    Since my mid-30s, when I wake in the morning, my vision in one eye (or sometimes both) is blurry with halos. By midday my vision is normal again.

    But if I spend several minutes in bed yawning with my eyes closed, I'm able to induce some tears, which lubricates my eyes. Can you shed any light on what might be causing it? I guess it's some kind of dry eye issue, but it isn't something that affects me at any other time of day.


    Answer:

    Vision issues that are worse in the morning and clear as the day goes on usually relate to problems with the cornea or the eye's outer surface. Halos result from scattered light rays entering the eye as they travel towards the retina, in the back of the eye. Two common conditions (among others) that are possible in this situation would be dry eyes and corneal swelling. You should see an ophthalmologist to determine if you have either condition.

    In dry eyes, if the eyelids do not form a tight seal, the surface can dry out overnight, and you may wake up with a sandy, gritty sensation or blurred vision. This would improve over the course of the day as the natural blinking action would help coat the surface of the eye with tears. When the surface is dry, it can become irregular, which would produce halos around lights.

    Other patients may have issues with corneal swelling. The cornea is normally 70-78 percent water. If it rises above that level, corneal transparency is reduced and halos can result from the light scatter. Cells located on the inside surface of the cornea are responsible for pumping fluid out of the cornea. In conditions like Fuchs' dystrophy, patients have fewer of these cells and often develop swelling overnight. Over the course of the day, tears evaporate from the surface of the eye, which restores the water content of the cornea back to normal.


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