Japanese Journal of Ophthalmology

, Volume 51, Issue 6, pp 456–461

In Vivo Measurements of Cone Photoreceptor Spacing in Myopic Eyes from Images Obtained by an Adaptive Optics Fundus Camera


  • Yoshiyuki Kitaguchi
    • Department of Applied Visual ScienceOsaka University Graduate School of Medicine
  • Kenichiro Bessho
    • Yodogawa Christian Hospital
  • Tatsuo Yamaguchi
    • Topcon Research Institute
  • Naoki Nakazawa
    • Topcon Research Institute
  • Toshifumi Mihashi
    • Topcon Research Institute
    • Department of Applied Visual ScienceOsaka University Graduate School of Medicine

DOI: 10.1007/s10384-007-0477-7

Cite this article as:
Kitaguchi, Y., Bessho, K., Yamaguchi, T. et al. Jpn J Ophthalmol (2007) 51: 456. doi:10.1007/s10384-007-0477-7



To determine the cone spacing in normal and myopic eyes from the images obtained by an adaptive optics (AO) fundus camera.


Nineteen eyes of 19 healthy volunteers with a mean ± SD spherical equivalent refractive error of −3.7 ± 3.3 diopters (D) (range, −0.3 to −11.1 D) and a mean axial length of 25.4 ± 1.61 mm (range, 23.4–28.0 mm) were investigated in a prospective cross-sectional study. An AO fundus camera equipped with a liquid crystal phase modulator was used to obtain the images of the photoreceptor mosaic. The spacing between the cones was calculated manually at a retinal locus 2° temporal from the center of the fovea. The magnification of the image was calculated by the axial length measured with an IOL Master.


The axial length was correlated with the refractive error (Pearson, r = −0.869; P < 0.001). The average cone spacing in the moderate- to high-myopia group (−6.5 ± 2.3 D, n = 9) was 4.71 ± 0.44 µm, which was significantly greater (P = 0.002) than the 3.90 ± 0.47 µm in the normal and low-myopia groups (−1.1 ± 0.9 D, n = 10). The cone spacing was significantly correlated with the axial length (r = 0.77, P < 0.001).


The AO fundus camera is capable of acquiring images of the photoreceptors in normal and myopic eyes. The greater spacing between cones in the myopia group is consistent with histological findings. These results suggest that retinal expansion should be considered in addition to Knapp's law when aniseikonia is evaluated in axial myopia. Jpn J Ophthalmol 2007;51:456–461 © Japanese Ophthalmological Society 2007

Key words

adaptive opticsmyopiaphotoreceptor

Copyright information

© Japanese Ophthalmological Society 2007