With the approval, Eylea can now be used to treat the thickening of the macula of the eye that sometimes follows central retinal vein occlusion - a blockage of the veins that carry blood away from the eye.

The macula is an area of the retina that is responsible for central vision and its thickening or swelling can lead to vision impairment.

Over 100,000 people in the United States are estimated to suffer from central retinal vein occlusion, the company said in a statement.

Eylea won U.S. approval last November to treat age-related macular degeneration - the leading cause of blindness in the elderly.

Since its launch, Eylea has surpassed Wall Street expectations for its sales. The strong numbers have also prompted Regeneron to raise its forecast for the drug's sales for the third time this year to between $700 million and $750 million in 2012.

New York-based Regeneron's shares were mostly flat at $145.22 late Friday afternoon on the Nasdaq.

(Reporting By Pallavi Ail in Bangalore; Editing by Sreejiraj Eluvangal)

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