ObjectiveTo observe the clinical features of bacillary layer detachment (BALAD) in neovascular age-related macular degeneration (nAMD) and its response to anti-vascular endothelial growth factor (VEGF) therapy. MethodsA retrospective clinical study. From July 2019 to July 2024, 188 patients (188 eyes) with nAMD who were continuously admitted to Tianjin University Aier Eye Hospital and received anti-VEGF drug treatment were included in the study. All eyes underwent best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) examinations. Treatment consisted of intravitreal anti-VEGF injections monthly for 3 months, followed by a pro re nata regimen. Based on the presence of BALAD on baseline OCT, eyes were divided into a BALAD group and a control group. BCVA was measured using a standard logarithmic visual acuity chart and converted to the logarithm of the minimum angle of resolution; central retinal thickness (CRT) was measured by OCT. Patients were followed for ≥12 months. Differences in CRT, BCVA, macular neovascularization (MNV) subtypes, and treatment outcomes at 12 months were compared between the two groups. The Scheirer-Ray-Hare test was used for non-normally distributed repeated measures data to compare interactions between time and group for BCVA and CRT; Spearman's rank correlation was used for correlation analysis of continuous variables between groups. ResultsThe number of eyes in the BALAD group and the control group was 33 (17.55%, 33/188) and 155 (82.45%, 155/188) respectively. Among the 33 eyes in the BALAD group, 21 eyes (63.64%, 21/33) had type 1 MNV, among which 18 eyes had polypoid choroidal vascular disease (PCV). There was no statistically significant difference in the gender composition ratio and MNV classification between the two groups of patients (χ2=2.09, 1.87, P＞0.05). There were statistically significant differences in age (t=-2.63), the proportion of PCV (χ2=13.73), and CRT (Z=-3.03) (P＜0.05). Twelve months after treatment, the cystic cavities of 84.85% (28/33) of the affected eyes in the BALAD group subsided. The BCVA of both groups of affected eyes improved over time (H=17.93, P＜0.05), but the overall BCVA of the BALAD group was still worse than that of the control group (H=17.80, P＜0.05). There was a significant difference in the improvement degree of CRT between the two groups (H=43.87, P＜0.05), and only in the control group was a significant positive correlation between BCVA and CRT (r=0.24, P＜0.05). ConclusionsIn nAMD, BALAD is associated with type 1 MNV, particularly the PCV subtype, and may serve as a biomarker for predicting anti-VEGF response. Although the BALAD structure is sensitive to anti-VEGF therapy and readily resolves, the limited functional improvement suggests it may be an imaging indicator of poor prognosis.