Small-cell lung cancer may directly affect the eye by metastatic proliferation or indirectly by paraneoplastic syndromes. The choroid is the most common site for uveal metastasis (90%); however, the iris can be involved in a smaller proportion of cases (incidence <10%). Blurred vision, pain, redness, photophobia, glaucoma, hyphema and visual field defects can arise from this metastatic involvement. The median survival time for patients with iris metastasis is reported to be 4 months. Secondary glaucoma can be managed with topical and oral treatment, transscleral cyclophotocoagulation, laser trabeculoplasty, anti-VEGF, Minimally Invasive Glaucoma Surgery (MIGS), filtering surgery, shunting surgery or enucleation. A case of primary small-cell lung cancer with iris metastasis is presented. The metastases produced an angle-closure glaucoma, which was refractory to topical treatment. Local radiotherapy was administered, obtaining a good local response.