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Thursday, July 24, 2014
Eye and Vision Care
See 'halos' around lights at night
I am a 45 year old female that has a sporadic problem with my vision. This problem becomes apparent after I leave a building and go outside. All outside lights, ie: car lights, street lights, signs, all appear to have a "halo" effect around them. This has been going on for 10+ years. When it first started I saw an eye specialist who conducted several tests and said he thought it was just from being tired.
Over the years, I have paid special attention when this happens and most of time I have not been tired. The only thing that I have noticed is that it usually occurs after I have left a building that uses florescent lights. Could this have something to do with it and does it sound like something I should have checked again? Currently it has only happened twice in the last 6 months.
"Haloes around lights" is a common eye symptom that can have many causes. The classic cause is narrow angle glaucoma, but this would be accompanied by redness, poor vision, pain, and increased pressure inside the eye. Haloes can also be caused by small cataracts or corneal swelling, both of which can scatter light entering the eye. But since your symptoms have been present for over ten years, and they are infrequent, I doubt that any of these conditions apply to you. Since you notice them upon leaving a building, they are most likely caused by a change in the diameter of your pupil. When we go from dark to bright environments, our pupils constrict; and this restricts the amount of light entering the eye. When we go from bright to darker environments, our pupils dilate to allow more light to enter. This normal change in pupil size usually occurs rapidly; but some patients have "sluggish" pupils, and it takes them longer to adjust to changing levels of illumination. If you are in good general health (no diabetes or other medical problems that may cause sluggish pupils), and do not experience these haloes frequently, I think they are just a minor inconvenience for you and not an eye disease that requires treatment. PS: Try wearing sunglasses when you exit a building during the day - they will permit a more gradual adjustment to the increased levels of light outside.
Robert D Newcomb, OD, MPH, FAAO
Professor Emeritus of Clinical Optometry
College of Optometry
The Ohio State University