Purpose.To report a patient with lattice corneal dystrophy type I (LCDI) who developed a triple anterior chamber after full-thickness lamellar keratoplasty (LKP).Methods.A 46-year-old woman underwent a full-thickness LKP in her right eye for visual disturbances caused by LCDI. Her visual acuity was 20/200 OD before surgery. A complete ophthalmic examination, including slit lamp biomicroscopy and optical coherence tomography (OCT), was performed before and after surgery. Molecular genetic analysis was performed on DNA extracted from the peripheral leukocytes.Results.The surgery was performed uneventfully; however, extra spaces posterior to the graft, along with the severe graft edema, were observed to form a triple anterior chamber a few days after surgery. The extra spaces resolved in 3 weeks with no surgical treatment, and her visual acuity improved to 20/20 OD without correction 3 months after surgery. The triple anterior chamber was clearly demonstrated by OCT, but not by slit lamp biomicroscopy. A heterozygous single base-pair transition (CGC to TGC, arginin to cysteine) was detected in codon 124 of theTGFBIgene in the patient.Conclusion.The separation of the graft and the host's deep corneal tissue and a Descemet's membrane detachment in the host's cornea caused the triple anterior chamber. The Descemet's membrane detachment demonstrated the weak adhesion of the stroma and the Descemet's membrane, probably resulting from a dysfunction of the TGFBI protein caused by the mutation of theTGFBIgene. OCT is useful for the objective documentation of the posterior corneal region even with severe corneal edema.