(e)  

Anterior segment optical coherence tomography (AS-OCT)
Study	Location	Year	Study design	Number of eyes	Major findings
Shousha et al. [13]	United States	2011	Prospective case series	Corneal/conjunctival intraepithelial neoplasia (CCIN) (7) Pterygia (7)	Ultra-high resolution (UHR) OCT demonstrated a thickened hyperreflective epithelium and abrupt transition from normal to hyperreflective epithelium in all CCIN cases. After medical treatment and clinical resolution, 4 cases demonstrated normal epithelial configuration on UHR-OCT while 3 cases showed residual disease that was clinically invisible. Continuation of treatment resulted in complete resolution of residual lesions on UHR-OCT.
Kieval et al. [26]	United States	2012	Prospective case series	Ocular surface squamous neoplasia (17) Pterygia (17)	UHR-OCT findings of OSSN and pterygia were well correlated to histopathologic findings. Both UHR-OCT and histopathologic specimens of OSSN demonstrated a thickened layer of epithelium, often with an abrupt transition from normal to neoplastic tissue. Meanwhile, both diagnostic modalities for pterygia showed a normal thin epithelium with underlying thickening of the subepithelial mucosal layers. Mean epithelial thickness on UHR-OCT for OSSN (346 μm) was significantly higher than for pterygia (101 μm) (p < 0.001). UHR-OCT had a high sensitivity (94%) and specificity (100%) for differentiating OSSN from pterygia.
Shousha et al. [27]	United States	2013	Prospective case series	OSSN (19) Primary acquired melanosis (8) Amelanotic melanoma (5) Nevi (2) Histiocytosis (1) Conjunctival lymphoma (6) Conjunctival amyloidosis (2) Pterygia (11)	UHR-OCT and histopathologic findings were closely correlated for all the examined ocular lesions. Specifically for OSSN, the epithelial layer was severely thickened and hyperreflective with an abrupt transition between normal and affected epithelium. In large lesions, a shadow from the hyperreflective epithelium may obscure the inferior border. The subepithelial layer was uninvolved in OSSN.
Nanji et al. [28]	United States	2015	Prospective case series	OSSN (21) Pterygia or pinguecula (24) Lymphoma (3) Pigmented conjunctival lesions (18) Salzmann nodular degeneration (6) Normal (10)	Commercially available HR-OCT is also capable of differentiating various lesions based on optical signs. Specifically in OSSN, HR-OCT shows epithelial thickening and hyperreflectivity.