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Retinal pigment epithelium melanin distribution estimated by polarisation entropy and its association with retinal sensitivity in patients with high myopia
  1. Akira Harimoto1,
  2. Ryo Obata1,
  3. Motoshi Yamamoto1,
  4. Nobuyori Aoki2,
  5. Masahiro Yamanari2,
  6. Satoshi Sugiyama2,
  7. Marie Kitano1,
  8. Asahi Fujita1,
  9. Takahiro Minami1,
  10. Kohei Ueda1,
  11. Keiko Azuma1,
  12. Tatsuya Inoue3,
  13. Makoto Aihara1,
  14. Satoshi Kato1
  1. 1Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
  2. 2Engineering Department, Tomey Corporation, Nagoya, Aichi, Japan
  3. 3Department of Ophthalmology and Micro-Technology, Yokohama City University, Yokohama, Japan
  1. Correspondence to Dr Ryo Obata, Ophthalmology, Tokyo Daigaku Daigakuin Igakukei Kenkyuka Igakubu, Bunkyo-ku, Tokyo 113-8655, Japan; robata-tky{at}umin.ac.jp

Abstract

Purpose To investigate retinal sensitivity of highly myopic eyes without choroidal neovascularisation (CNV) or patchy chorioretinal atrophy (PCA) and investigated its association with anatomical characteristics including melanin distribution at the retinal pigment epithelium (RPE), which was evaluated with polarisation-sensitive optical coherence tomography (PS-OCT).

Design Retrospective consecutive observational cohort study.

Methods We included highly myopic eyes (refractive error ≤−8.0 dioptres or axial length of ≥26.5 mm) from patients at the University of Tokyo Hospital. Retinal sensitivity was measured by microperimetry at 25 sectors within 6 degrees from the fovea. Depolarisation value, which reflected melanin pigmentation, was measured by a clinical prototype of PS-OCT and was parameterised as polarimetric entropy. Retinal sensitivity or entropy at the RPE in high myopia was compared with emmetropic control subjects. The association of retinal sensitivity with age, axial length, entropy, or choroidal thickness was assessed in per-eye and per-sector analysis.

Results Twenty-three highly myopic eyes (age, 66.6±12.3 years) were included. The average retinal sensitivity was 25.3±3.0 dB, which was significantly decreased compared with the control (p<0.0001). The average entropy at the RPE in the highly myopic eyes was significantly lower than in the control (p<0.0001). Univariate analysis followed by multivariate analysis showed that besides age, axial length or choroidal thickness, RPE entropy was independently associated with retinal sensitivity (β=4.4; 95% CI 0.5 to 8.3; p=0.03).

Conclusions Decreased depolarisation at the RPE measured with PS-OCT, which reflected altered melanin pigmentation, was independently associated with reduced retinal sensitivity in patients with early stages of myopic maculopathy without CNV or PCA.

  • imaging
  • macula
  • pathology
  • retina
  • choroid

Data availability statement

Data are available on reasonable request. No additional information.

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Data availability statement

Data are available on reasonable request. No additional information.

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Footnotes

  • Contributors Conception and design of study: RO. Acquisition of data: AH, RO, MY, NA, MY, SS, KU, KA, TI. Analysis and/or interpretation of data: AH, RO, MY, NA, MY, SS, KA. Drafting the manuscript: AH, RO. Revising the manuscript critically for important intellectual content: AH, RO, MY, NA, MY, SS, MK, AF, TM, KU, KA, TI, MA, SK.

  • Funding This research was supported by AMED under Grant Number JP19he1302011.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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