Joint Filer Information

Names:	Deerfield Capital L.P., Deerfield Partners, L.P., Deerfield Management Company, L.P., Deerfield International Limited, Deerfield Special Situations Fund, L.P., Deerfield Special Situations Fund International Limited, Deerfield Private Design Fund, L.P., Deerfield Private Design International, L.P.
Address:	Deerfield Capital, L.P., Deerfield Partners, L.P., Deerfield Management Company, L.P., Deerfield Special Situations Fund, L.P., Deerfield Private Design Fund, L.P., Deerfield Private Design International, L.P.:
	780 Third Avenue, 37th Floor
	New York, NY 10017
	Deerfield International Limited, Deerfield Special Situations Fund International Limited:
	c/o Citi Hedge Fund Services (B.V.I.) Ltd.
	Bison Court, Columbus Centre, P.O. Box 3460
	Road Town, Tortola, D8
	British Virgin Islands
Designated Filer:	James E. Flynn
Issuer and Ticker Symbol:	ISTA Pharmaceuticals, Inc. [ISTA]
Date of Earliest Transaction Reported:	May 4, 2011

The undersigned, Deerfield Capital, L.P., Deerfield Partners, L.P., Deerfield Management Company, L.P., Deerfield International Limited, Deerfield Special Situations Fund, L.P., Deerfield Special Situations Fund International Limited, Deerfield Private Design Fund, L.P. and Deerfield Private Design International, L.P.  are jointly filing the attached Statement of Changes in Beneficial Ownership on Form 4 with James E. Flynn with respect to the beneficial ownership of securities of ISTA Pharmaceuticals, Inc.

Signatures:
DEERFIELD CAPITAL, L.P.
By:	J.E. Flynn Capital LLC, General Partner
By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact
DEERFIELD PARTNERS, L.P.
By:	Deerfield Capital, L.P., General Partner
By:	J.E. Flynn Capital LLC, General Partner
By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact

DEERFIELD MANAGEMENT COMPANY, L.P.
By:	Flynn Management LLC, General Partner
By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact
DEERFIELD INTERNATIONAL LIMITED
By:	/s/ Darren Levine
	Darren Levine, Attorney-In-Fact
DEERFIELD SPECIAL SITUATIONS FUND, L.P.
By:	Deerfield Capital, L.P., General Partner
By:	J.E. Flynn Capital LLC, General Partner
By:	/s/ Darren Levine
	Darren Levine, Attorney-in-Fact

DEERFIELD SPECIAL SITUATIONS FUND INTERNATIONAL LIMITED

By:	/s/ Darren Levine
	Darren Levine, Attorney-in-Fact
DEERFIELD PRIVATE DESIGN FUND, L.P.
By:	Deerfield Capital, L.P., General Partner
By:	J.E. Flynn Capital LLC, General Partner
By:	/s/ Darren Levine
	Darren Levine, Attorney-in-Fact

DEERFIELD PRIVATE DESIGN INTERNATIONAL, L.P.

By:	Deerfield Capital, L.P., General Partner
By:	J.E. Flynn Capital LLC, General Partner
By:	/s/ Darren Levine
	Darren Levine, Attorney-in-Fact