Clinical in vivo confocal microscopy (IVCM) is a relatively new technique of corneal evaluation that permits non-invasive imaging of corneal structures on the cellular level. Precise anatomic characterization of corneal structures, including corneal nerves, can be rapidly performed with high resolution.

Evaluation of the corneal nerve layer with IVCM provides a method of direct visualization of peripheral small fiber nerves and a quantifiable assessment of nerve abnormalities in a low risk, non-invasive manner. Therefore, our goal is to develop a non-invasive diagnostic protocol as a quantitative tool for the evaluation of DPN. The protocol and the tool we seek to develop could ultimately be used in large-scale clinical trials and in clinical practice to assess DPN severity and progression.

We hypothesize that in vivo confocal imaging of the corneal nerve layer is a clinically viable method to assess and quantify systemic peripheral nerve health. We emphasize that this imaging method can be used in both humans and animal models to provide quantifiable, longitudinal data on the same live individual to advance our understanding of the development and progression of DPN, and to evaluate treatment effectiveness.

Inclusion Criteria:

• diabetes

Exclusion Criteria:

• history of laser eye surgery, corneal disease, multiple sclerosis, Parkinson's disease, or any known systemic neuropathy.

Subjes\cts with diabetes with none, mild or severe neuropathy