How Can We Diagnose Ocular Surface Squamous Neoplasia With Optical Coherence Tomography?

Aim: We aimed to evaluate the effectiveness of optical coherence tomography (OCT) in the differential diagnosis of anterior segment diseases such as ocular surface squamous neoplasia (OSSN) and pterygium. Methods: Patients who were pre-diagnosed with either OSSN (21) or pterygium (19) between January 2020 and November 2022 were included in this retrospective study. Anterior segment photographs and anterior segment optical coherence tomography (AS-OCT) measurements were obtained from each patient. Excisional or incisional biopsy materials underwent pathological evaluation. Results: Preoperative AS-OCT images of the patients with OSSN showed similarities with histopathological specimens. Both ocular and pathological specimens appeared to have a thicker epithelial layer with a distinct change from healthy to neoplastic epithelium. Preoperative AS-OCT images of individuals with pterygium were also comparable with histopathological samples. Both pathological and AS-OCT images of the pterygium patients showed a normal thickness epithelium and a thickened subepithelial layer under the epithelium. The mean epithelial thickness measured with AS-OCT in OSSN patients was found to be 295.3 ± 111.3 µm, while it was 80.7 ± 43.4 µm in pterygium patients. The difference was statistically significant (P<0.001). The receiver operating characteristic (ROC) curve analysis revealed a cut-off value of 97 µm for the differential diagnosis of OSSN from pterygium, with a sensitivity of 100% and specificity of 94.7%. Conclusions: AS-OCT can be used as a noninvasive diagnostic tool for the evaluation of ocular surface lesions. Its ability to distinguish between OSSN and pterygium is demonstrated by the statistically significant difference in epithelial thickness and the significant morphological association with histopathological findings.