The Queen had surgery last month to remove a cataract from her eye, Buckingham Palace has said.
Her Majesty “successfully underwent a short, planned procedure”, a spokesman confirmed.
She was treated as a day patient at the private King Edward VII hospital in London.
In recent weeks, the monarch has been seen wearing sunglasses at events including Buckingham Palace garden parties and the Royal Windsor Horse Show.
She did not cancel or postpone any engagements, the spokesman said.
A cataract is a clouding of the lens in the eye, leading to a decrease in vision.
During the operation, which takes between 30 and 45 minutes, the cloudy lens is removed and replaced with a plastic one.
It is the most common operation in the UK, from which it takes four to six weeks to recover.
Cataracts are more likely to develop if there is a family history of them.
In 1995, when she was 95, the Queen Mother spent the night at the King Edward VII Hospital after having a cataract removed from her left eye.