BackgroundTo assess the safety and efficacy of two subthreshold parameters (5 and 15% duty cycle (DC)) compared to standard ETDRS (early treatment of diabetic retinopathy study) continuous wave (CW) laser.MethodsIn this prospective randomized study, 30 eyes from 20 patients with non-center involving macular edema were randomized into 3 different groups: 5% DC, 15% DC and CW navigated modified ETDRS laser treatment. Titration in subthreshold groups was performed with 30% of the threshold power, decided with microsecond pulses. CW laser was titrated to a barely visible burn. All patients underwent microperimetry, thickness measurements and visual acuity examinations at baseline, 6 weeks and 12 weeks post treatment.ResultsAt three months follow up, retinal sensitivity was significantly reduced in the CW group by − 2.2 dB whereas in both subthreshold groups, retinal sensitivity increased by 2.4 dB for 5% and 1.9 dB for 15% DC with no significant difference. Retinal volume (mm3) decreased in both subthreshold groups by 0.08 ± 0.3 and 0.12 ± 0.11 in 5 and 15% DC group respectively. Whereas the CW group showed volume increase of 0.55 ± 0.92 (p = 0.02 and 0.01 for 5 and 15% DC groups). Visual acuity remained stable in all 3 groups (− 0.7 letter in 5% DC; 2.11 letters in 15% DC and 0.88 in CW with no significant difference).ConclusionSubthreshold microsecond laser was shown to be safe and effective with both 5 and 15% DC as compared to conventional photocoagulation with ETDRS parameters. The 15% DC setting trended to achieve better anatomical, visual and functional outcomes.Trial registrationRetrospectively registered (NCT03571659, 06/26/2018).
Purpose: Recent publications have reported that the deep capillary plexus (DCP) area of the foveal avascular zone (FAZ) is significantly larger in eyes following pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RRD) repair when compared with controls. To the best of the authors’ knowledge, there have been no publications on the evaluation of the macular microvasculature using optical coherence tomography angiography (OCTA) in post–pneumatic retinopexy (PnR) eyes. Therefore, the purpose of this study was to investigate FAZ-area changes following PnR. Methods: This retrospective cohort included 19 patients with macula-off RRD who underwent PnR repair. Each patient’s fellow eye was used as a control. The FAZ area in the superficial capillary plexus and DCP was investigated with OCTA and the areas were measured by 2 masked graders. Results: Both superficial (PnR: 0.22 [0.16-0.35] vs control: 0.24 [0.18-0.34] mm2; P = .715) and deep (PnR: 0.56 [0.51-0.76] vs control: 0.7 [0.59-0.89] mm2; P = .105) FAZ areas were not significantly different between eyes. Conclusions: Our results suggest that the lack of FAZ-area enlargement after PnR repair may indicate that there is less ischemic damage to the retinal capillary plexus in the fovea when compared with that described in the literature for PPV. The PIVOT trial demonstrated that PnR is associated with superior visual acuity and less metamorphopsia when compared with PPV at 1 year. The results of the current study may provide insight into the potential advantages of PnR. Further studies are needed to elucidate how the macular microvasculature is affected after RRD and to clarify how the FAZ area changes following PnR and PPV.
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