**5.3 Corneal and ocular surface pathology**

UHR-OCT can detect early secondary corneal amyloidosis as a dense spot in Bowman's layer [61]. Corneas with Thiel-Behnke Dystrophy have extensive deposits of hyper-reflective material in a saw-tooth pattern on the surface of Bowman's layer [60]. UHR-OCT images may become adjunct to clinical evaluation and provide an optical biopsy image in other conditions. Eyes with spheroidal degeneration show cystic structures in Bowman's layer and superficial stroma, and Salzmann's nodular degeneration has hyper-reflective material which replaces anterior stroma and Bowman's layer with thin epithelium [60] (**Figure 2**). Limbal stem cell deficiency exhibits a hyper-reflective material which replaces Bowman's layer as well as the anterior stroma, with irregular overlying epithelium (**Figure 3**).

### **Figure 2.**

*A prototypical cross-sectional UHR-OCT image of a human cornea with keratoconus; focal disintegration of Bowman's layer (white arrow), focal stromal thinning (yellow arrow).*

#### **Figure 3.**

*A prototypical cross-sectional UHR-OCT image of a human cornea with Limbal stem cell deficiency; a hyperreflective material (yellow stars) which replaces anterior stroma and Bowman's layer with irregular overlying epithelium (red stars).*
