Utility of high-resolution anterior segment optical coherence tomography in the diagnosis and management of sub-clinical ocular surface squamous neoplasia

Abstract

Background: To evaluate the frequency and characteristics of sub-clinical ocular surface squamous neoplasia (OSSN) detected by high-resolution anterior segment tomography (HR- OCT) in patients with clinically unapparent disease following topical treatment.

Methods: A retrospective chart review of patients with OSSN identified through a pharmacy database at the Bascom Palmer Eye Institute from January 2013 to December 2018 was conducted. Patients undergoing primary therapy with topical 5-fluorouracil 1% (5-FU) (4 times a day for 7 days with a 21-day break) or interferon-alpha-2b (IFN) (4 times a day) were reviewed. Patients were separated into two groups. Group 1 included individuals whose clinical resolution of OSSN aligned with complete resolution on HR-OCT. Group 2 (sub-clinical OSSN group) included individuals with clinical OSSN resolution but with features of persistent disease on HR- OCT. Patients excluded included those treated at an outside institution and those who used topical therapy as a surgical adjunct.

Results: A total of 95 patients (95 eyes) were reviewed. Sub-clinical OSSN was detected at a frequency of 17% in our study patients (n = 16 patients, 9 treated with 5-FU and 7 treated with IFN). In the 16 individuals, the mean time to clinical resolution was 3.6 ± 1.0 cycles for 5-FU and 4.0 ± 0.0 months for IFN. An additional 2.1 ± 0.8 cycles for 5-FU and 1.2 ± 0.4 months for IFN were needed to achieve HR-OCT resolution of OSSN. Recurrence in Group 1 was noted in 10 patients (12%) while no recurrences occurred in Group 2, the cohort with subclinical disease that received the extended medical therapy. The mean follow-up was 24.0 ± 17.9 months.

Conclusion: We found that at least 17% of individuals with apparent clinical resolution of OSSN have sub-clinical disease detected on HR-OCT. This information can be used to optimize treatment and extend therapy past the point of clinical resolution.

Keywords: High-resolution optical coherence tomography; Ocular surface imaging; ocular surface lesions; Ocular surface squamous neoplasia; Sub-clinical ocular surface squamous neoplasia.

Fig. 1

HR-OCT of OSSN. a A slit lamp photograph of the right eye of a superior flat/opalescent ocular surface squamous neoplasia (arrow). Dashed white line represents area of OCT scan. b High resolution optical coherence tomography (HR-OCT) reveals thickened and hyperreflective epithelium (*) with an abrupt transition point (arrow)

Fig. 2

HR-OCT of sub-clinical OSSN. a Slit lamp image of the left eye of a flat/opalescent ocular surface squamous neoplasia (arrow) emanating from the head of a subtle pterygium (marked by an x). Note opalescent tissue on the cornea from 7 to 9 o’clock. b High resolution optical coherence tomography (HR-OCT) revealed thickened, hyperreflective, epithelium (marked by an *) with an abrupt transition (arrow). Directly below is a subepithelial “stringy” hyperreflectivity consistent with the pterygium (marked by an o). c After 4 cycles of 5-flourouracil (5-FU), the flat/opalescent lesion at the head of the pterygium was no longer clinically visible. d HR-OCT reveals improvement but persistent sub-clinical disease (marked by an *) with residual hyperreflective thickened epithelium. e After an additional 2 cycles of 5-FU, the lesion remains clinically resolved. f Now the HR OCT confirms normalized, thin epithelium (arrow). Sub-epithelial scarring consistent with the pterygium remains as expected

Fig. 3

Kaplan-Meier Recurrence Time. Kaplan-Meier survival curve depicting time from clinical resolution to recurrence in the two groups