Analysis of cone mosaic reflectance properties in healthy eyes and in eyes with nonproliferative diabetic retinopathy over time

Letizia Mariotti, Nicholas Devaney, Giuseppe Lombardo, Marco Lombardo

Research output: Contribution to journalArticlepeer-review


PURPOSE. We investigate the reflectance properties of the cone mosaic in adaptive optics (AO) images of healthy subjects and subjects with nonproliferative diabetic retinopathy (NPDR) over time. METHODS. We acquired images of the parafoveal cone mosaic over 5 years in 12 healthy subjects and in six patients with mild NPDR. We analyzed the parameters of the cone intensity histogram distribution (mean, SD, and skewness), two metrics of the cone mosaic texture (sharpness and entropy), and two novel metrics (cone/intercone intensity and slope of the variogram). Each metric was calculated on the same four retinal locations (200 × 200 μm areas, 2° from the fovea along the four meridians) over time for each subject. RESULTS. The histogram distributions of cone intensities were similar between the two study groups. However, the cone/intercone intensity, slope of the variograms and entropy showed a significant difference between healthy and NPDR subjects (P = 0.036, P = 0.002, P = 0.014, respectively). All parameters, except for mean cone intensity, did not change with time in this study. CONCLUSIONS. We observed significant differences in cone mosaic reflectance properties between healthy eyes and eyes with NPDR, in its spatial organization and in its intensity, especially between directional and nondirectional backscattering. We introduced a novel method for the study of the spatial distribution of cone reflectance, the variogram, which was able to quantify differences of the spatial dependence of cone intensities over a short range between NPDR and healthy eyes.

Original languageEnglish
Pages (from-to)4057-4067
Number of pages11
JournalInvestigative Ophthalmology and Visual Science
Issue number10
Publication statusPublished - Aug 1 2017


  • Adaptive optics
  • Cone reflectance
  • Cones
  • Diabetic retinopathy
  • Photoreceptors

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


Dive into the research topics of 'Analysis of cone mosaic reflectance properties in healthy eyes and in eyes with nonproliferative diabetic retinopathy over time'. Together they form a unique fingerprint.

Cite this