Comparison of retinal function and macular structure after 27G pars plana vitrectomy with minimal heads-up versus standard illumination in patients with idiopathic epiretinal membranes: A pilot randomized study.

Abstract

Purpose: To analyse the clinical benefits of using the NGENUITY 3D Visualization System in vitreoretinal surgery with low levels of endoillumination, focusing on functional and structural retinal protection in patients with idiopathic epiretinal membranes (ERM).

Design: Prospective, randomized, comparative study.

Methods: Forty pseudophakic patients (29♀, 11♂; age 60-80 years) with ERM underwent 27G pars plana vitrectomy (PPV) and were randomly divided into two groups: Group I (20 eyes, 3D heads-up NGENUITY system, endoillumination 0.5 Lm) and Group II (20 eyes, standard microscope [Hi-R 900], endoillumination 3.2 Lm). Preoperative and 6-months postoperative evaluations included slit-lamp examination, intraocular pressure (IOP, Pascal tonometer), Distance Best Corrected Visual Acuity (DBCVA, logMAR), Central Subfoveal Thickness (CST), Retinal Nerve Fibre Layer Thickness (RNFL, OCT), Pattern ERG (PERG), multifocal ERG (mfERG), flash ERG (ERG, ISCEV standards), and retinal sensitivity (HFA macula test). Surgery time, xenon light exposure, ERM/ILM peeling time, fundus autofluorescence (FAF), metamorphopsia incidence, and intra-/postoperative adverse events were analysed. Results were statistically evaluated (p < 0.05).

Results: Slit-lamp examination and IOP results were normal in both groups. DBCVA improved significantly (p = 0.005) in both groups but was better for Group I, albeit not statistically significant. CST and RNFL thickness decreased significantly in both groups (p = 0.01) and did not differ between them. In Group I, increased cone and ganglion cell function was registered, with PERG showing significantly higher increases in P50 and N95 wave amplitudes (p = 0.01) compared with Group II. In mfERG, an increase in P1-wave response density in Ring 1 (p = 0.01) was observed only in Group I. In ERG, Group I showed better rod (Ab, p = 0.04), cone (Aa, p = 0.03), and amacrine cell (scotopic OPS ∑A01 + A02 + A03, p = 0.02) function compared with Group II. Foveal threshold in the HFA macula test increased significantly only in Group I (p = 0.03). No significant differences were found in autofluorescence results, surgery times, xenon light exposure, or ERM and ILM peeling times between groups. Postoperatively, the frequency of absent or reduced severity of metamorphopsia was higher in Group I (71.4%) compared with Group II (61.5%). No intraoperative or postoperative adverse events occurred.

Conclusion: Our preliminary results suggest that in patients with idiopathic ERM, 6 months after PPV using the NGENUITY 3D system with low levels of endoillumination, better retinal function was achieved compared with the standard PPV procedure, possibly due to reduced retinal phototoxicity. Further long-term studies are necessary to confirm that conclusion.