A team of researchers from Michigan suggests that central corneal thickness (CCT) increases as diabetic peripheral neuropathy (DPN) becomes more severe in patients with diabetes because of an increase in stromal thickness.

The cross-sectional study evaluated 34 participants—nine were healthy controls, 16 had mild DPN and nine had severe DPN. Participants underwent clinical examination, nerve conduction studies and quantitative sensory testing and ultrasound pachymetry.

The researchers found that CCT was lowest in the control group and highest in the severe DPN group; the mean CCT was 552.7 ±29.2μm among controls, 583.4 ±25.0μm among patients with mild DPN and 613.3 ±28.8μm for those with severe DPN. Stromal thickness also increased as DPN progressed, the study notes; the mean stromal thickness was 439.5 ±23.5μm in the control group, 478.9 ±37.5μm in the mild DPN group and 494.5 ±39.1μm in the severe DPN group.

The study concludes that “CCT increase associated with DPN has important clinical implications, including glaucoma progression, keratoconus susceptibility and intraocular pressure assessment and should be accounted for when evaluating patients with diabetes.”

Kumar N, Pop-Busui R, Musch DC, et al. Central corneal thickness increase due to stromal thickening with diabetic peripheral neuropathy severity. Cornea. 2018;37(9):1138-42.