Changes in in vivo confocal microscopic findings of ocular surface squamous neoplasia during treatment with topical interferon alfa-2b.

PURPOSE

To evaluate in vivo confocal microscopy (IVCM) findings of ocular surface squamous neoplasia (OSSN) during treatment with topical interferon alfa-2b (IFN alfa-2b).

METHODS

In this prospective interventional case series, 20 eyes from 20 patients with OSSN were treated with topical IFN alfa-2b 3 million IU/mL four times a day. Treatment was continued for 2 or 3 months after clinical resolution. IVCM was done at baseline, on a monthly basis, and at the end of treatment. Confocal images were evaluated in conjunction with clinical findings during treatment. Limbal dendritic cell (DC) density within the involved areas was calculated manually in confocal images.

RESULTS

Topical therapy resulted in clinical resolution of neoplasia in 80% of eyes. Main features of OSSN on IVCM were hyper-reflectivity of epithelium, demarcation line between neoplastic and normal epithelium, and pleomorphic cells. These findings became less prominent in response to IFN alfa-2b therapy. However, some degree of residual epithelial hyper-reflectivity could be detected in 9 (56.2%) subjects who responded to therapy at time of treatment cessation. Limbal DCs density within involved areas was significantly increased at month 1 follow-up compared to baseline only in responders (P < .0001). There was a trend toward higher limbal DCs density in responders to topical IFN alfa-2b than non-responders (208.6 ± 53.5 vs. 153.1 ± 48.2 cell/mm, respectively; P = .08) at month 1 follow-up.

CONCLUSIONS

IVCM is proposed as an adjunctive tool for monitoring OSSN during topical treatment. IVCM documents epithelial cell response as well as limbal DC density increase during topical IFN therapy.