98%
921
2 minutes
20
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.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1167/iovs.17-21932 | DOI Listing |
J Opt Soc Am A Opt Image Sci Vis
May 2025
We develop an efficient coding model to address how a population of retinal ganglion cells (RGCs) can optimally combine signals from the retinal cone mosaic to maximize information transfer through the optic nerve. The model takes into account the redundancies inherent in color natural images and predicts how they should be reduced in order to make the best use of channel capacity in the optic nerve, given metabolic constraints, wiring constraints, and input and channel noise. RGCs are modeled as a set of linear-nonlinear neurons whose instantaneous firing rate is computed via a weighted sum of cone responses from a simulated L- and M-cone mosaic, followed by a rectifying nonlinearity.
View Article and Find Full Text PDFRom J Ophthalmol
July 2025
"Ovidius" University of Constanţa, Constanţa, Romania.
Objective: Our objective was to assess retinal microcirculation and photoreceptor parameters in both healthy individuals and patients with vascular retinal diseases using adaptive optics ophthalmoscopy. This technology enhances optical system resolution to 2 µm by correcting wavefront aberrations, revolutionizing in vivo studies of ocular structures.
Materials And Methods: Our study examined the clinical applications of adaptive optics in both healthy individuals and patients with vascular retinal diseases, including nonproliferative diabetic retinopathy, proliferative diabetic retinopathy, and macular telangiectasia (MacTel) type 2.
Sci Rep
May 2025
Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, 450003, China.
Dark without pressure (DWP) is the more darkly pigmented area of the retina in the fundus, typically exhibits relatively distinct boundaries, and varies in shape, size, and distribution across different individuals. Previous studies have concluded that DWP alone has no impact visual acuity, visual field, or other visual functions. This study aims to reveal the multimodal imaging manifestations of DWP in high myopia and to explore its impact on retinal function.
View Article and Find Full Text PDFFolia Parasitol (Praha)
May 2025
Sorbonne Universite, CNRS, Biologie integrative des organismes marins, BIOM, Observatoire Oceanologique, Banyuls-sur-Mer, France.
While the identification of adult monogeneans primarily relies on morphological criteria, the morphology of a number of monogenean larvae (oncomiracidia) is to this day scarcely described. Yet, oncomiracidium plays a crucial role in the life cycle of the parasite, being responsible for the detection and localisation of its host, as well as for its attachment to this host. Few studies investigated the external morphological structures related to these functions, especially in Monopisthocotylea.
View Article and Find Full Text PDFRom J Ophthalmol
May 2025
"Ovidius" University of Constanţa, Constanţa, Romania.
Objective: We used adaptive optics ophthalmoscopy to assess retinal microcirculation and photoreceptor parameters in healthy individuals and patients with vascular retinal diseases. This technology enhances optical system resolution to 2 µm by correcting wavefront aberrations, revolutionizing in vivo studies of ocular structures.
Methods: Our study examined the clinical applications of adaptive optics in both healthy individuals and patients with vascular retinal diseases, including nonproliferative diabetic retinopathy, proliferative diabetic retinopathy, and macular telangiectasia (MacTel) type 2.