Corneal Confocal Microscopy as a Measure of Diabetic Neuropathy
- 1Department of Ophthalmology, University of Michigan, Ann Arbor, Michigan
- 2Department of Neurology, University of Michigan, Ann Arbor, Michigan
- Corresponding author: Brian C. Callaghan, .
Distal symmetric polyneuropathy is the most common pattern of nerve injury in patients with diabetes (1,2). In fact, up to 50% of patients with diabetes will develop distal symmetric polyneuropathy at some point during their illness (3). Currently, the only effective treatment to prevent this prevalent condition is glucose control (4). Unfortunately, demonstrating an improvement in neuropathy over time has been much more difficult to achieve than preventing progression (5). Possible explanations for the lack of improvement in outcome measures include a lack of an effective treatment and/or a lack of a sensitive test for nerve fiber repair.
No consensus exists as to which neuropathy outcomes should be obtained after a therapeutic intervention, and all currently available options have advantages and disadvantages. Clinical assessments and scales have the advantage of taking into account patients’ symptoms and neurologic examination, but recent work has indicated that this approach may have poor reproducibility (6). Nerve conduction studies have long been used in studies of glucose control in type 1 and type 2 diabetes, and they have the advantage of being quantitative. However, improvement in nerve conduction studies may take years to manifest, and these studies do not assess small fiber nerve function, which are often the first nerves to be injured and perhaps the first to be repaired. Intraepidermal nerve fiber density …