Merge Healthcare, a provider of healthcare enterprise imaging and interoperability solutions, has signed a definitive merger agreement to acquire Ophthalmic Imaging Systems (OIS).

OIS is a provider of digital imaging and informatics solutions for ophthalmology and other medical specialties.

Merge Healthcare will add ophthalmic imaging and informatics to its current portfolio of enterprise imaging solutions for radiology, cardiology and orthopaedics; a suite of products for clinical trials; software for financial and pre-surgical management, and applications that fuel the modality vendors in the world.

Merge Healthcare CEO Jeff Surges said with OIS they will add the important specialty of ophthalmology.

"The OIS solution suite and client base of prominent clinics and hospital networks are an ideal complement to our enterprise imaging capabilities and will be a great addition to our solutions portfolio," Surges said.

Pending customary closing conditions and the successful completion of a California Fairness Hearing, the transaction is expected to close in the third quarter of 2011.