Long-term OCT volumetric analysis of the preretinal space in patients with vitreomacular adhesion (VMA)

This retrospective observational cohort study aimed to descriptively evaluate longitudinal changes in the architecture of the preretinal space, defined as the space between the posterior vitreous cortex (PVC) and the internal limiting membrane (ILM), associated with vitreomacular adhesion (VMA), using volumetric measurements derived from three-dimensional optical coherence tomography (OCT) scans. Three-dimensional retina scans were acquired using the Optovue RTVue XR OCT Avanti device to assess changes at the vitreomacular interface over a minimum follow-up period of 30 months, with examinations performed every 4 or 6 months. Long-term longitudinal data from 17 eyes were included in the analysis. Volumetric measurements of the preretinal space were obtained through automated segmentation of the ILM and PVC across the 3D Retina scan sets, followed by manual verification of ILM and PVC delineation in all 141 B-scans per volume to ensure segmentation accuracy. Preretinal space volumes and adhesion areas were subsequently calculated using OCTAnnotate software. Across the ETDRS macular regions, a consistent descriptive increase in preretinal space volume was observed during follow-up, with mean total volume changing from 1.42 mm³ at baseline (95% CI: 1.13–3.12) to 2.60 mm³ at the final visit (95% CI: 2.28–4.92). Spontaneous vitreomacular detachment occurred in 8% of the eyes, a rate within the lower range reported in previous natural history studies of VMA and VMT. Notably, the study observed relatively good visual acuity values in the cohort with a mean best-corrected visual acuity of 0.009 ± 0.026 (logMAR). The largest preretinal space volumes were most frequently observed in the superior outer macular regions (70.1% of eyes), followed by increased volumes in the nasal quadrant. Longitudinal observations suggested that volume expansion initially predominated in the superior and temporal regions, subsequently involving inferior temporal regions, with comparatively smaller changes in the nasal regions. Overall, the preretinal space volume demonstrated a progressive increase over time, most prominently in the superior outer macular regions. These spatial patterns are consistent with degenerative vitreous changes and may reflect gravity-related effects on vitreous structure, with posterior vitreous detachment appearing to progress preferentially from the superior quadrants. Given the limited sample size, analyses were descriptive and no formal inferential statistical testing was performed.