My 75-year-old female patient complains of vision that goes blurred for a few seconds and then becomes sharp again. She has recently had cataract surgery and an intraocular lens implant in her right eye without any documented complications. Her monocular visual acuities are 6/5 and she has no retinal or optic disc abnormalities. What is going on?
Intermittent blurred vision can have several possible causes.
Problems with the tear film can cause intermittent blurred vision, so take a good look at the cornea, tear film, and lid margins.
For people with some accommodative ability, general fatigue such as late-night tiredness can reduce the ability to focus at near and this can cause intermittent blurred vision. This is unlikely to be the cause in your patient’s case because she does not have any accommodative ability.
Floaters drifting over the visual axis can also cause intermittent blurred vision. Ask the patient if they notice floaters and look for them when you examine the internal structures of the eyes. If they are new floaters then also look for a retinal tear and/or retinal hole and or retinal detachment.
Rarely an intraocular lens can move around in the eye and this can cause intermittent blurred vision.
In a medico-legal case, I was asked for an opinion on a patient who was complaining of blurred vision with the vision returning to normal after a few seconds of blurriness. This happened several times a day. The eye specialist took comfort from the fact that the vision returned to normal and did not further investigate this symptom or seek help from another eye specialist. The patient also had a persistent and severe headache for the last month. A few weeks later the patient completely lost vision in one eye due to giant cell arteritis. It seems that the intermittent blurred vision was caused by interrupted blood supply to the optic nerve. While a complete but transient monocular loss of vision is more common in giant cell arteritis, this case and others that have been documented show that a few seconds of blurred vision could be a sign of giant cell arteritis.
Consider these possibilities for your patient and take the appropriate management action depending on what you find
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