Table 2.

Optical signs of ocular surface lesions

Lesion	Epithelial Layer		Subepithelial layer
	Thickness	Reflectivity
Normal	Thin epithelium (about 45–70um)	Dark corneal epithelium; mild hyper-reflectivity over limbus and conjunctiva	No masses, no shadowing, anterior portion of conjunctival epithelium hyperreflective
OSSN	Severely thickened; inferior border of lesion may be partially obscured by shadowing in very thick lesions	Strongly hyper-reflective, usually with abrupt transition from normal to abnormal	Not involved in CCIN; unable to comment for SCC (none in current study)
Pingueculum	Normal to slightly thickened epithelium	Mildly hyper-reflective	Dark subepithelial tissue mass near limbus
Pterygium	Normal to slightly thickened epithelium	Mildly hyper-reflective	Highly hyper-reflective subepithelial lesion; hyper-reflective layer seen between Bowman’s and corneal epithelium in corneal scans
Lymphoma	Normal thickness	Normal	Hypo-reflective and homogenous subepithelial mass; surrounding hyper-reflective layer of uninvolved tissue and shadowing of underlying tissue
Salzmann’s nodular degeneration	Thin epithelium, usually thinner than normal	Normal	Dense, subepithelial, hyper-reflective material just anterior to Bowman’s layer
Flat melanosis	Normal thickness	Hyper-reflectivity of the basal epithelium ± patchy hyper-reflectivity within epithelium	No involvement
Nevi	Normal thickness	Mildly hyper-reflective but often with strong reflectivity of basal epithelium	Subepithelial mass with mild shadowing of the underlying tissue; cysts often seen
Melanoma	Normal thickness to somewhat thickened epithelium	Mildly hyper-reflective but often with strong reflectivity of basal epithelium	Hyper-reflective subepithelial mass with obscuration of the underlying tissue (and in some, the posterior portion of the lesion) due to shadowing; rarely cysts.

OSSN=ocular surface squamous neoplasia; CCIN=corneal and conjunctival intraepithelial neoplasia; SCC=squamous cell carcinoma