To clarify the histologic basis of bacillary layer detachment (BALAD) through a review of current literature and an analysis of retinal imaging. Methods: We reviewed the literature for previous reports of BALAD. An analysis of retinal images was performed to support anatomic conclusions. Results: A total of 164 unique patients with BALAD on optical coherence tomography (OCT) were identified from the published literature. Twenty-two underlying etiologies, all associated with subretinal exudation, were identified. Forty-one different OCT terminologies were found. The defining OCT feature of BALAD was a split at the level of the photoreceptor inner segment myoid creating a distinctive intraretinal cavity. Resolution of BALAD was followed by a rapid restoration of the ellipsoid zone. Histology of age-related macular degeneration eyes suggests that individual photoreceptors can shed inner segments. Further, detachment of the entire layer of inner segments is a common postmortem artefact. We propose that BALAD occurs when outwardly directed forces promoting attachment of photoreceptor outer segments to the retinal pigment epithelium exceed the tensile strength of the photoreceptor inner segment myoid. Conclusion: Our review serves to strengthen the OCT nomenclature “bacillary layer detachment”, based on specific reflectance information obtained by OCT and previously published histologic observations.