Distribution of cone density, spacing and arrangement in adult healthy retinas with adaptive optics flood illumination

PLoS One. 2018 Jan 16;13(1):e0191141. doi: 10.1371/journal.pone.0191141. eCollection 2018.

Abstract

The aim of this article is to analyse cone density, spacing and arrangement using an adaptive optics flood illumination retina camera (rtx1™) on a healthy population. Cone density, cone spacing and packing arrangements were measured on the right retinas of 109 subjects at 2°, 3°, 4°, 5° and 6° of eccentricity along 4 meridians. The effects of eccentricity, meridian, axial length, spherical equivalent, gender and age were evaluated. Cone density decreased on average from 28 884 ± 3 692 cones/mm2, at 2° of eccentricity, to 15 843 ± 1 598 cones/mm2 at 6°. A strong inter-individual variation, especially at 2°, was observed. No important difference of cone density was observed between the nasal and temporal meridians or between the superior and inferior meridians. However, the horizontal and vertical meridians differed by around 14% (T-test, p<0.0001). Cone density, expressed in units of area, decreased as a function of axial length (r2 = 0.60), but remained constant (r2 = 0.05) when cone density is expressed in terms of visual angle supporting the hypothesis that the retina is stretched during the elongation of the eyeball. Gender did not modify the cone distribution. Cone density was slightly modified by age but only at 2°. The older group showed a smaller density (7%). Cone spacing increased from 6,49 ± 0,42 μm to 8,72 ± 0,45 μm respectively between 2° and 6° of eccentricity. The mosaic of the retina is mainly triangularly arranged (i.e. cells with 5 to 7 neighbors) from 2° to 6°. Around half of the cells had 6 neighbors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Female
  • Humans
  • Light*
  • Male
  • Middle Aged
  • Optics and Photonics
  • Retina / anatomy & histology*
  • Retinal Cone Photoreceptor Cells*
  • Young Adult

Grant support

This project was founded by the Conseil Général de l’Essonne (Action de Soutien à la Technologie et à la Recherche en Essonne) and by Imagine Eyes, Orsay, France. This research was supported by an Initiative Doctorale Interdisciplinaire grant. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.