A Case Series of Bacillary Layer Detachment (BALAD) in Neovascular Age-Related Macular Degeneration (nAMD): A Novel Optical Coherence Tomography (OCT) Biomarker

Bacillary layer detachment (BALAD) is a newly recognized optical coherence tomography (OCT) finding, defined as a split at the photoreceptor inner segment (myoid zone) resulting in a dome-shaped intraretinal fluid cavity. BALAD has been reported in various chorioretinal diseases and may serve as a novel structural OCT biomarker of severe exudation. We present a case series of BALAD in neovascular age-related macular degeneration (nAMD) to characterize its multimodal imaging features and discuss its diagnostic and prognostic significance. Three patients with active nAMD exhibited BALAD on spectral-domain OCT. In each instance, OCT cross-sections showed a sharply demarcated hyporeflective intraretinal cavity beneath an intact external limiting membrane (ELM) and above the ellipsoid zone (EZ). OCT angiography (OCTA) revealed an underlying high-flow choroidal neovascular network corresponding to the BALAD in all cases. All three patients initially had significant visual impairment. Two patients were treated with serial intravitreal anti-vascular endothelial growth factor (VEGF) injections, resulting in rapid resolution of the BALAD cavity, reabsorption of subretinal and intraretinal fluid, and marked improvement in best-corrected visual acuity (e.g., from 20/400 to 20/40). The third patient, who declined treatment, developed persistent BALAD with progressive subfoveal fibrosis and no visual recovery. BALAD in nAMD indicates an aggressive disease phenotype with intense outer retinal fluid accumulation and photoreceptor layer schisis. Prompt anti-VEGF therapy was associated with anatomical recovery and vision improvement in the treated cases. Recognizing BALAD on OCT and OCTA is clinically important, as it differentiates intraretinal from subretinal pathology and underscores the need for early, aggressive treatment to mitigate irreversible retinal damage in nAMD.