2020–2021 BCSC Basic and Clinical Science Course™
8 External Disease and Cornea
Chapter 8: Systemic Disorders With Corneal and Other Anterior Segment Manifestations
The most common disorder of carbohydrate metabolism, diabetes mellitus (DM), has nonspecific corneal manifestations. See BCSC Section 1, Update on General Medicine, for detailed discussion of DM.
Diabetic keratopathy includes superficial punctate epitheliopathy, epithelial erosions, hypoesthesia, persistent epithelial defects, and corneal edema. These changes occur with increasing severity and duration of the disease. Surgical removal of diabetic epithelium results in the loss of the basal cells and basement membrane, often leading to prolonged healing difficulties. Faint vertical folds in the Descemet membrane and deep stroma (Waite-Beetham lines) are not specific to DM but may represent early corneal endothelial dysfunction and increased stromal hydration.
An increase in glycosylated hemoglobin is related to poor control of DM and may correlate with poor corneal healing in addition to progressive retinopathy.
Diabetes mellitus is not a contraindication to PK or other corneal surgery. Measures that can improve diabetic epitheliopathy include the following:
perioperative management of meibomian gland dysfunction (increased comorbidity with DM)
minimizing epithelial debridement at surgery
avoiding toxic medications
using therapeutic contact lenses, exercising caution because of the risk of infection
Srinivasan S, Shehadeh-Mashor R, Slomovic AR. Corneal manifestations of metabolic diseases. In: Mannis MJ, Holland EJ, eds. Cornea. Vol 1. 4th ed. Philadelphia: Elsevier; 2017:620–644.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.