ABSTRACT
AIM:
To quantitatively evaluate the effect of the combined use of 577-nm subthreshold micropulse macular
laser (SML) and multi-point mode pan
retinal laser photocoagulation (PRP) on severe non-proliferative
diabetic retinopathy (NPDR) with central-involved diabetic
macular edema (CIDME) using
optical coherence tomography angiography (OCTA).
METHODS:
In this observational
clinical study, 86
eyes of 86 NPDR
patients with CIDME
who underwent SML and PRP
treatment were included. Images were obtained 1d before
laser and post-
laser (1d, 1wk, 1, 3, and 6mo) using AngioVue
software 2.0. Best corrected
visual acuity (BCVA, LogMAR), foveal avascular zone area (FAZ), choriocapillary flow area (ChF), parafoveal vessel density (PVD),
capillary density inside disc (CDD), peripapillary
capillary density (PCD), macular
ganglion cell complex thickness (mGCCT), central macular thickness (CMT), and subfoveal choroidal thickness (ChT) were compared between pre- and post-
laser treatment.
RESULTS:
BCVA remained stable during 6mo post-
laser therapy (pre-
laser vs 6mo post-
laser 0.53±0.21 vs 0.5±0.15, P>0.05). PVD, ChF, ChT, CMT, and mGCCT significantly increased 1d post-
laser therapy [pre-
laser vs 1d post-
laser superficial PVD (%), 40.51±3.42 vs 42.43±4.68; deep PVD (%), 42.66±3.67 vs 44.78±4.52; ChF, 1.72±0.21 vs 1.9±0.12 mm2; ChT, 302.45±69.74 vs 319.38±70.93 µm; CMT, 301.65±110.78 vs 320.86±105.62 µm; mGCCT, 105.71±10.72 vs 115.46±9.64 µm; P<0.05]. However, PVD, ChF and ChT decreased to less than baseline level at 6mo post-
laser therapy (pre-
laser vs 6mo post-
laser superficial PVD (%), 40.51±3.42 vs 36.32±4.19; deep PVD (%), 42.66±3.67 vs 38.76±3.74; ChF, 1.72±0.21 vs 1.62±0.09 mm2; ChT, 302.45±69.74 vs 289.61±67.55 µm; P<0.05), whereas CMT and mGCCT decreased to baseline level at 6mo post-
laser therapy (CMT, 301.65±110.78 vs 297.77±90.23 µm; mGCCT, 105.71±10.72 vs 107.05±11.81 µm; P>0.05). Moreover, FAZ continuously increased while CDD and PCD continuously decreased in 6mo after
laser therapy. CMT and ChT had a significant positive correlation with ChF and PVD in most post-
laser stages.
CONCLUSION:
During a 6-month follow-up period after combined use of SML and PRP
therapy, BCVA remained stable and there was a decreased trend in
macular edema.
Blood flow increased at 1d post-
laser therapy and reduced at 6mo post-
laser therapy.