Hi. I'm online and happy to answer your question today.
A common cause for your sclera to become dark, where it was once white, is a condition called scleromalacia
The most common area for this to occur is in the 3 and 9 oclock positions on your eye as you look in a mirror. They are usually oblong shaped.
Many times this condition can be seen in people who have rheumatoid arthritis. Normally it is nothing to be concerned about but it wouldn't hurt to ask your ophthalmologist about it during your next appointment.
Here is a picture of a fairly large area of scleral thinning (scleromalacia):
Does this make sense to you?
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