Development of a prognostic surgical index using optical coherence tomography for large macular holes: a retrospective multicenter study.

Background: Herein, we developed a new index called the drawbridge index to predict surgical outcomes and assessed its value in guiding surgical decision-making for large macular holes (MHs) with diameters of 400-550 μm.

Methods: A total of 48 eyes with large MHs (diameters of 400 to 550 μm), which had undergone vitrectomy with internal limiting membrane (ILM) peeling, were included and retrospectively analyzed. Based on optical coherence tomography images, base diameter, minimum linear diameter, the macular hole index (MHI), diameter hole index (DHI), and traction hole index (THI) were measured and calculated. The drawbridge index was calculated using the software ImageJ. It was determined by calculating the sum of the arm lengths extending from the break point of the outer plexiform layer (OPL) to the retinal pigment epithelium (RPE) on both sides of the macular hole, as well as the sum of the lengths from the starting point of the distorted OPL to the RPE in the vertical direction, and the difference between them then dividing by base diameter. The effectiveness of these predictive indices in prognosing "closed" versus "not closed" outcomes, and their correlation with outcome indicators, including best-corrected visual acuity, central foveal thickness, and ellipsoid zone defect length, was assessed. Furthermore, the area under the receiver operating characteristic curve (AUC) and a cutoff value were calculated for the drawbridge index. In the second part, a total of 21 patients were enrolled in the validation group, and the drawbridge index was utilized to guide surgical decisions for the ILM techniques.

Results: Significant differences were observed between the "closed" and "not closed" groups using the drawbridge index (P < 0.05). The drawbridge index was significantly correlated with postoperative best-corrected visual acuity, ellipsoid zone defect, and central foveal thickness. It exhibited an AUC value of 0.92, and the cutoff value of 1.03 demonstrated a sensitivity of 87.50% and a specificity of 80.00%. Assisted by the drawbridge index, a 100% closure rate was achieved in patients in the validation group.

Conclusion: The drawbridge index may be reliable and useful for making surgical decisions regarding ILM manipulation for large MHs.