Ultra-deep vs. standard swept-source optical coherence tomography for posterior vitreous detachment assessment: a retrospective comparative study.

BACKGROUND

The efficacy of ultra-deep mode of swept-source optical coherence tomography (SS-OCT) for evaluating posterior vitreous detachment (PVD) remains unknown. The study aimed to compare the ultra-deep mode (scan length: 26 mm, scan depth: 12 mm) and standard mode (scan length: 16 mm, scan depth: 3 mm) of SS-OCT in PVD assessment.

METHODS

This retrospective study included patients diagnosed with epiretinal membrane or macular hole at Zhongshan Ophthalmic Center between May 2023 and August 2024, encompassing both affected and contralateral fellow eyes. All eyes underwent two SS-OCT scanning modes (the ultra-deep mode and standard mode) with 18-line radial scans centered on the fovea. PVD staging consistency was compared between the two modes, as well as the visibility of the detached posterior hyaloid membrane (PHM) and Weiss ring in cases of complete PVD.

RESULTS

A total of 178 eyes from 100 patients were analyzed. The inter-mode agreement for PVD staging was high (Kappa =0.981, P<0.001), with 100.0% agreement in diagnosing complete PVD. Among 107 eyes with complete PVD, detached PHM was detected in 98.1% using the ultra-deep mode versus 47.7% using the standard mode (P<0.001). The ultra-deep mode visualized completely detached PHM in more quadrants than the standard mode, particularly in the inferior quadrants (98.1% vs. 44.9%, P<0.001). Weiss ring was observed at a higher rate with the ultra-deep mode compared to the standard mode (15.9% vs. 3.7%, P=0.005).

CONCLUSIONS

The ultra-deep mode and standard mode of SS-OCT showed high consistency in PVD staging. The ultra-deep mode provided superior visualization of completely detached PHM, thus enhancing diagnostic certainty for complete PVD.