Open AccessChanges in entropy on polarized-sensitive optical coherence tomography images after therapeutic subthreshold micropulse laser for diabetic macular edema: A pilot study
Author(s) -
Koji Ueda,
Tomoyasu Shiraya,
Fumiyuki Araki,
Yukihiko Hashimoto,
Motoshi Yamamoto,
Masahiro Yamanari,
Takashi Ueta,
Takahiro Minami,
Nobuyori Aoki,
Satoshi Sugiyama,
Han Zhou,
Keisuke Totsuka,
Taku Toyama,
Katsuhisa Sugimoto,
Ryo Obata,
Satoshi Kato
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0257000
Subject(s) - optical coherence tomography , ophthalmology , medicine , diabetic retinopathy , retinal , retinal pigment epithelium , endocrinology , diabetes mellitus
Purpose To investigate the dynamics of the healing process after therapeutic subthreshold micropulse laser (SMPL) for diabetic macular edema (DME) using polarization-sensitive optical coherence tomography (PS-OCT). Methods Patients with treatment-native or previously-treated DME were prospectively imaged using PS-OCT at baseline, 1, 2, 3, and 6 months. The following outcomes were evaluated: changes in the entropy value per unit area (pixel 2 ) in the retinal pigment epithelium (RPE) on the B-scan image; changes in the entropy value in each stratified layer (retina, RPE, choroid) based on the ETDRS grid circle overlaid with en face entropy mapping, not only the whole ETDRS grid area but also a sector irradiated by the SMPL; and the relationship between edema reduction and entropy changes. Results A total of 11 eyes of 11 consecutive DME patients were enrolled. No visible signs of SMPL treatment were detected on PS-OCT images. The entropy value per unit area (pixel 2 ) in the RPE tended to decrease at 3 and 6 months from baseline (35.8 ± 17.0 vs 26.1 ± 9.8, P = 0.14; vs 28.2 ± 18.3, P = 0.14). Based on the en face entropy mapping, the overall entropy value did not change in each layer in the whole ETDRS grid; however, decrease of entropy in the RPE was observed at 2, 3, and 6 months post-treatment within the SMPL-irradiated sectors (P < 0.01, each). There was a positive correlation between the change rate of retinal thickness and that of entropy in the RPE within the SMPL-irradiated sector at 6 months (r 2 = 0.19, P = 0.039). Conclusion Entropy measured using PS-OCT may be a new parameter that facilitates objective monitoring of SMPL-induced functional changes in the RPE that could not previously be assessed directly. This may contribute to a more promising therapeutic evaluation of DME. Clinical trial This clinical study was registered in UMIN-CTR (ID: UMIN000042420).