The primary objective of this clinical trial is to evaluate the performance of the Nvision Volumetric Laser Endomicroscopy (VLE) system to visualize subsurface tissue in subjects undergoing esophagogastroduodenoscopy (EGD) and to identify work-flow and training implications for introducing this new imaging modality.

Inclusion Criteria:

• Males and females over the age of 18 years.
• Patients with either suspected BE presenting for endoscopy or patients with documented BE presenting for follow-up endoscopy likely to require a biopsy or patients presenting for endoscopy for non-BE related conditions other than esophageal varices.
• Ability to provide written, informed consent.
• Females who are able to become pregnant, are willing to take a pregnancy test.

Exclusion Criteria:

• Patients on anticoagulation undergoing high risk procedures in accordance to American Society For Gastrointestinal Endoscopy (ASGE) guideline for the management of antithrombotic agents for endoscopic procedures (2009).
• Patients with esophageal varices that preclude biopsies.
• Presence of an esophageal mass that precludes full distention of the balloon from the Nvision balloon guide sheath.
• Patients with esophageal strictures that would prevent adequate expansion of the balloon from the Nvision balloon guide sheath.
• Patients with known inflammatory disease, esophageal tears or ulcers, which would prohibit full distention of the balloon from the Nvision balloon guide sheath.
• Patients with known eosinophilic esophagitis.
• Patients that are pregnant.
• Patients with a history of hemostasis disorders.

Males and females >18 years of age undergoing esophagogastroduodenoscopy (EGD) for suspected or confirmed Barrett's esophagus (BE)or for non-BE related conditions other than esophageal varices.