When primary acquired melanosis (PAM) with atypia affects the tarsal conjunctiva, a radical surgery can be mutilating, requiring reconstructive surgery of the eyelid. Topical chemotherapy associated to local cryotherapy may be an alternative. A 64-year-old Caucasian female presented with diffuse PAM of the right eye involving the inferior tarsal conjunctiva, fornix, and inferotemporal bulbar conjunctiva. Histological study showed a PAM with atypia (C-MIN 5). Given the extent of the lesion and its location, a wide mutilating excision was ruled out. Topical interferon alpha 2b (IFN-α2b) treatment (1,000,000 IU/mL, 4 times a day) was administered during 10 weeks. However, the regression was very slow. Then local cryotherapy was proposed (8 s at −80°C per application) to the entire pigmented lesion. This afforded progressive depigmentation, which was completed 2 months later. No recurrence of the lesion has been noted during 3 years of follow-up. The combination of the two procedures reduces IFN-α2b eyedrop administration time, enhancing patient compliance. The combination may eradicate the tumor without compromising ocular cosmesis.