Abstract
Purpose :
The ability to diagnose ocular surface neoplasia with the aid of imaging modalities is improving, but still hindered by the limitations of currently available techniques. Inverse spectroscopic optical coherence tomography (IS-OCT) is an emerging technique capable of detecting nanoscale ultrastructural differences in pre-neoplastic and neoplastic states within gut mucosa. Two-photon autofluorescence imaging (TPI) can detect autofluorescence of metabolic markers: nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), alterations in which have been associated with neoplasia. In this pilot study, we investigated the utility of IS-OCT and TPI in diagnosing lesions of the ocular surface by evaluating excised conjunctival and corneal lesions.
Methods :
With IRB approval, informed consent was obtained from patients undergoing excision of ocular surface lesions at Boston Medical Center by a single surgeon. The surgeon used a 1 or 2mm biopsy punch to separate a central portion of the excised lesion, leaving the lateral margins intact, and sent the peripheral portion directly to the pathology lab and the central portion for ex vivo IS-OCT and TPI. Immediately after imaging, the central specimen was also sent to the pathology lab for histological diagnosis. The IS-OCT and TPI findings were correlated to the histologic findings.
Results :
There were 7 specimens imaged by IS-OCT. Based on histologic findings, 1 of the specimens was diagnosed as a conjunctival papilloma and 6 were diagnosed as pterygium. A quantitative measurement correlating to the ultrastructural compaction measured by IS-OCT, D value, was 2-fold higher in papilloma compared to pterygium (3.73 vs 1.81 ± 0.88) [Figure 1]. The papilloma also displayed roughly 8-fold higher NADH autofluorescence intensity by TPI compared to pterygium (25.98 vs. 3.19 ± 1.03).
Conclusions :
Compared to pterygium, conjunctival papilloma, which is not malignant but shares some clinical features in common with ocular surface squamous neoplasia, had higher D and higher NADH, which have been associated with higher malignant potential and higher cellular proliferation, respectively. We demonstrate proof of concept that IS-OCT and TPI can be applied to the examination of ocular surface lesions. Further studies of the utilization of IS-OCT and TPI for ocular surface neoplasia are ongoing.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.