Retinal sensitivity assessed by microperimetry and its topographic correlation with macular structure by optical coherence tomography following macular hole surgery: a cross-sectional study.

Abstract

Background: To evaluate retinal sensitivity (RS) assessed by microperimetry in the macular region of patients undergoing surgical repair of idiopathic macular hole (MH), and to investigate the topographic correlation between RS and both total macular thickness (TMT) and ganglion cell complex (GCC) thickness obtained by optical coherence tomography (OCT), establishing point-by-point anatomic correspondence between sensitivity measurements and their structurally matched retinal areas, six months after successful MH surgery with internal limiting membrane (ILM) peeling.

Methods: Observational, analytical, cross-sectional study including 40 consecutive patients who underwent 25-gauge pars plana vitrectomy with ILM peeling for idiopathic MH at a single center (Juiz de Fora Eye Hospital, Brazil) between 2022 and 2024, with a minimum postoperative follow-up of six months. An age- and sex-matched control group of 43 healthy subjects was recruited for comparison. All patients were pseudophakic at the time of assessment. Retinal sensitivity was assessed using the MP-3 microperimeter (Nidek Technologies, Italy) with a 44-point stimulus grid (Goldmann size III, 4 - 2 staircase strategy) distributed across the central 20°, designed to match the nine-sector ETDRS grid. Macular structure was evaluated by swept-source OCT (DRI OCT Triton; Topcon, Japan). TMT and GCC thickness (µm) were measured in all nine ETDRS sectors. Spearman correlation coefficients were used to assess topographic structure-function relationships. Multivariate linear regression was performed to identify independent predictors of postoperative foveal RS and mean RS.

Results: All 40 MH eyes achieved anatomic closure. Best-corrected visual acuity (BCVA) improved significantly postoperatively (0.94 ± 0.22 to 0.54 ± 0.26 logMAR; p < 0.001) but remained inferior to controls (0.12 ± 0.09 logMAR; p < 0.001). Mean RS was significantly lower in patients than in controls (24.78 ± 2.73 vs. 26.46 ± 1.77 dB; p = 0.002; AUC = 0.721), with significant reductions observed at the fovea and in six of eight parafoveal/perifoveal sectors. The temporal outer sector showed the highest discriminative capacity (AUC = 0.774). Mean GCC thickness (µm) was significantly reduced postoperatively compared to both preoperative values (107.55 ± 11.80 vs. 95.97 ± 13.31 μm; p < 0.001) and controls (104.26 ± 7.95 μm; p = 0.001). Significant positive topographic correlations were found between RS and TMT at the fovea (ρ = 0.542; p < 0.001) and in all four outer ETDRS sectors (ρ ranging from 0.546 to 0.645; all p < 0.001), as well as between RS and GCC thickness in multiple sectors (ρ ranging from 0.240 to 0.391; p < 0.05). In the multivariate model, specific regional GCC and TMT sector thicknesses were independent predictors of postoperative foveal RS, while preoperative BCVA and MH morphometric parameters showed limited independent predictive value.

Conclusions: Despite successful anatomic MH closure and significant BCVA improvement, retinal sensitivity remained significantly reduced across most extrafoveal ETDRS macular sectors at six months postoperatively. These functional deficits were accompanied by significant GCC thinning in sectors anatomically remote from the macular hole and structurally intact preoperatively. The spatial distribution of these changes is incompatible with damage attributable to the macular hole itself and strongly suggests a causal role for the mechanical trauma of ILM peeling. These findings support the integration of microperimetry as a complementary functional outcome measure in the postoperative assessment of macular hole surgery.