PURPOSE: To evaluate the integrity of the outer retinal layers-outer nuclear layer (ONL), external limiting membrane (ELM), ellipsoid (EZ), and interdigitation band (IZ)-using spectral-domain optical coherence tomography and estimate their effect on visual acuity in retinitis pigmentosa (RP). METHODS: A cross-sectional study was performed in the Ophthalmology Department of Hospital de Braga, Portugal. Patients ...