LONDON — The cause of Jane Austen’s mysterious death at the age of 41 has been much pondered over the years. Was it a hormonal disorder? Cancer? Complications from drinking unpasteurized milk?

New research by the British Library suggests a more dramatic possibility: arsenic poisoning.

Researchers at the library, working with the London optometrist Simon Barnard, recently examined three pairs of glasses believed to have belonged to Austen, and said that they show evidence that her vision severely deteriorated in her final years.

That kind of deterioration further suggests cataracts, and cataracts may indicate arsenic poisoning, Sandra Tuppen, a curator of archives and manuscripts at the library, wrote in a blog post on the library’s website on Thursday.

“If Austen did develop cataracts,” as the glasses indicate, Dr. Tuppen wrote, one likely cause is “accidental poisoning from a heavy metal such as arsenic.”