A catheter configured for imaging objects substantially in focus is described herein. An imaging device is disposed on the distal end of the catheter. The imaging device has an effective focal plane that is located in front of the imaging device. The catheter also includes a transparent focal instrument that has an outer periphery that is positioned at the effective focal plane of the imaging device, to enable objects in contact with the outer periphery of the transparent focal instrument to be imaged substantially in focus.