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


    Question:

    Since my mid-‘30s (I am 47 now), I've had a strange problem with my eyes in the mornings. If I open them right after waking up, I'll find that the vision in one or the other (or occasionally both) will be a little blurry, with halos around lights. This lasts for a few hours, and by late morning I can feel them clearing. By midday they have returned to normal. The only thing that seems to help is to spend several minutes in bed with my eyes closed, continually yawning to induce some tears, which I guess is lubricating the eyes (incidentally the vision can get quite "cloudy" as I'm doing this, presumably from the sleep in my eyes). None of the opticians I have visited over the years have heard of this problem before. 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.


    Answer:

    Vision issues that are worse in the morning and clear up as the day goes on usually relate to problems with the ocular surface. Halos happen whenever the light rays entering the eye get scattered as they travel through the eye towards the retina. 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 can have an issue 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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