[Relationship between macular hole cavity cross-sectional area and retinal blood flow density and its impact on...

Objective: To investigate the correlation between the cross-sectional area of the macular hole (MH) cavity and the blood flow density in different retinal layers, as well as the impact of cavity size on preoperative and postoperative retinal function in patients with idiopathic macular holes (IMH). Methods: A retrospective cohort study was conducted. Clinical data were collected from 18 patients (18 eyes) diagnosed with IMH who underwent vitrectomy combined with internal limiting membrane peeling at Shanxi Eye Hospital affiliated to Shanxi Medical University from August 2019 to December 2021. Visual acuity, best-corrected visual acuity (BCVA), spectral-domain optical coherence tomography (SD-OCT), optical coherence tomography angiography (OCTA), and multifocal electroretinography (mfERG) were performed preoperatively and at 1, 3, and 6 months postoperatively. Blood flow density data were collected for the overall retina, macular center fovea, and parafoveal regions, and the cavity cross-sectional area was measured using ImageJ software. Ten healthy subjects without retinal abnormalities who underwent mfERG at Shanxi Eye Hospital affiliated to Shanxi Medical University during the same period were included as a control group. One eye was randomly selected for each subject, with 5 left eyes and 5 right eyes. Statistical analysis was performed using Pearson correlation analysis, independent samples t-test, and repeated measures analysis of variance. Results: All 18 IMH patients had unilateral disease, including 3 males and 15 females, with an average age of (64.22±4.33) years and a duration of illness of 75 (38, 120) days. In the control group, consisting of 10 subjects, 4 were male and 6 were female, with an average age of (63.67±6.96) years. Preoperatively, all 18 affected eyes exhibited a macular hole cavity, which closed and disappeared one month postoperatively. The total cavity cross-sectional area was (4.84±2.28) mm2, with an average area of (0.27±0.13) mm². The cavity cross-sectional area was positively correlated with the MH height (r=0.82, P<0.001), ellipsoid zone disruption diameter (r=0.74, P<0.001), and preoperative BCVA (r=0.62, P=0.006). The cavity cross-sectional area was positively correlated with the blood flow density of the superficial macular center fovea (r=0.47, P=0.049) and negatively correlated with the blood flow density of the deep retina (r=-0.50, P=0.033) and deep parafoveal blood flow density (r=-0.65, P=0.003). Compared to healthy eyes in the control group, IMH eyes showed decreased amplitudes of P1 and N1 waves in mfERG, prolonged P1 wave latency except at ring 1 (2.18° outward from the foveal center), and prolonged N1 wave latency except at ring 2 (7.46° outward from the foveal center) and 5 (29.75° outward from the foveal center) (all P<0.05). The cavity cross-sectional area was only related to the preoperative latency of the N1 wave at ring 2 (r=0.64, P=0.004) and had an effect on the changes in the preoperative and postoperative latency of P1 and N1 waves at ring 1 and 5 (F=4.94, 5.96; P=0.042, 0.027). Time changes had no effect on the preoperative and postoperative amplitudes and latencies of mfERG P1 and N1 waves (all P>0.05), but the interaction between cavity cross-sectional area and time had statistical significance for the amplitudes of P1 at ring 1 and N1 at ring 2(F=6.89, 3.76; P=0.003, 0.035). Conclusions: In patients with IMH, a larger macular hole cavity cross-sectional area is associated with lower blood flow density, particularly in the deep parafoveal region, poorer visual acuity, and decreased retinal function at 7.46° outward from the foveal center.