scholarly journals Human foveal cone photoreceptor topography and its dependence on eye length

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Yiyi Wang ◽  
Nicolas Bensaid ◽  
Pavan Tiruveedhula ◽  
Jianqiang Ma ◽  
Sowmya Ravikumar ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Adaptive Optics ◽  
Axial Length ◽  
Visual Angle ◽  
Cone Photoreceptor ◽  
Foveal Vision ◽  
Cone Mosaic ◽  
New Generation ◽  
Myopic Progression ◽  
Cone Density

We provide the first measures of foveal cone density as a function of axial length in living eyes and discuss the physical and visual implications of our findings. We used a new generation Adaptive Optics Scanning Laser Ophthalmoscope to image cones at and near the fovea in 28 eyes of 16 subjects. Cone density and other metrics were computed in units of visual angle and linear retinal units. The foveal cone mosaic in longer eyes is expanded at the fovea, but not in proportion to eye length. Despite retinal stretching (decrease in cones/mm2), myopes generally have a higher angular sampling density (increase in cones/deg2) in and around the fovea compared to emmetropes, offering the potential for better visual acuity. Reports of deficits in best-corrected foveal vision in myopes compared to emmetropes cannot be explained by increased spacing between photoreceptors caused by retinal stretching during myopic progression.

scholarly journals Human Foveal Cone Photoreceptor Topography and its Dependence on Eye Length

2019 ◽  
Author(s):  
Yiyi Wang ◽  
Nicolas Bensaid ◽  
Pavan Tiruveedhula ◽  
Jianqiang Ma ◽  
Sowmya Ravikumar ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Adaptive Optics ◽  
Axial Length ◽  
Visual Angle ◽  
Cone Photoreceptor ◽  
Foveal Vision ◽  
Cone Mosaic ◽  
New Generation ◽  
Myopic Progression ◽  
Cone Density

AbstractWe provide the first measures of foveal cone density as a function of axial length in living eyes and discuss the physical and visual implications of our findings. We used a new generation Adaptive Optics Scanning Laser Ophthalmoscope to image cones at and near the fovea in 28 eyes of 16 subjects. Cone density and other metrics were computed in units of visual angle and linear retinal units. The foveal cone mosaic in longer eyes is expanded at the fovea, but not in proportion to eye length. Despite retinal stretching (decrease in cones/mm2), myopes generally have a higher angular sampling density (increase in cones/deg2) in and around the fovea compared to emmetropes, offering the potential for better visual acuity. Reports of deficits in best-corrected foveal vision in myopes compared to emmetropes cannot be explained by increased spacing between photoreceptors caused by retinal stretching during myopic progression.

scholarly journals Computer-assisted photoreceptor assessment on Heidelberg Engineering Spectralis™ High Magnification Module™ images

2021 ◽  
Author(s):  
Timo W. F. Mulders ◽  
B. Jeroen Klevering ◽  
Carel B. Hoyng ◽  
Thomas Theelen
Keyword(s):  
Adaptive Optics ◽  
Nearest Neighbor ◽  
Retinal Disease ◽  
Computer Assisted ◽  
High Magnification ◽  
Cone Photoreceptor ◽  
Friedman Test ◽  
The Third ◽  
Progression Marker ◽  
Cone Density

Abstract Purpose To evaluate reliability and repeatability of computer-assisted measurements of cone photoreceptor metrics on Heidelberg Engineering Spectralis™ High Magnification Module (HMM™) Automatic Real-time Tracking (ART™) images. Methods We analyzed HMM™ images in three separate study arms. Computer-assisted cone identification software was validated using an open-access adaptive optics (AO) dataset. We compared results of the first arm to data from AO and histology. We evaluated intersession repeatability of our computer-assisted cone analysis in the second arm. We assessed the capability of HMM™ to visualize cones in the presence of pathology in the third arm. Results We included 10 healthy subjects in the first arm of our study, 5 additional healthy participants in the second arm and 5 patients in the third arm. In total, we analyzed 225 regions of interest on HMM™ images. We were able to automatically identify cone photoreceptors and assess corresponding metrics at all eccentricities between 2 and 9° from the fovea. Cone density significantly declined with increasing eccentricity (p = 4.890E-26, Friedman test). With increasing eccentricity, we found a significant increase in intercell distance (p = 2.196E-25, Friedman test) and nearest neighbor distance (p = 1.997E-25, Friedman test). Cone hexagonality ranged between 71 and 85%. We found excellent automated intersession repeatability of cone density counts and spacing measurements. In pathology, we were also able to repeatedly visualize photoreceptors. Conclusion Computer-assisted cone photoreceptor analysis on Spectralis™ HMM™ images is feasible, and most cone metrics show excellent repeatability. HMM™ imaging may be useful for photoreceptor analysis as progression marker in outer retinal disease.

scholarly journals Persistent Dark Cones in Oligocone Trichromacy Revealed by Multimodal Adaptive Optics Ophthalmoscopy

2021 ◽  
Vol 13 ◽  
Author(s):  
Joanne Li ◽  
Tao Liu ◽  
Oliver J. Flynn ◽  
Amy Turriff ◽  
Zhuolin Liu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Visual Acuity ◽  
Color Vision ◽  
Adaptive Optics ◽  
Retinal Sensitivity ◽  
Photoreceptor Layer ◽  
Normal Visual Acuity ◽  
Normal Color Vision ◽  
Retinal Disorders ◽  
Cone Density

Dark cone photoreceptors, defined as those with diminished or absent reflectivity when observed with adaptive optics (AO) ophthalmoscopy, are increasingly reported in retinal disorders. However, their structural and functional impact remain unclear. Here, we report a 3-year longitudinal study on a patient with oligocone trichromacy (OT) who presented with persistent, widespread dark cones within and near the macula. Diminished electroretinogram (ERG) cone but normal ERG rod responses together with normal color vision confirmed the OT diagnosis. In addition, the patient had normal to near normal visual acuity and retinal sensitivity. Occasional dark gaps in the photoreceptor layer were observed on optical coherence tomography, in agreement with reflectance AO scanning light ophthalmoscopy, which revealed that over 50% of the cones in the fovea were dark, increasing to 74% at 10° eccentricity. In addition, the cone density was 78% lower than normal histologic value at the fovea, and 20–40% lower at eccentricities of 5–15°. Interestingly, color vision testing was near normal at locations where cones were predominantly dark. These findings illustrate how a retina with predominant dark cones that persist over at least 3 years can support near normal central retinal function. Furthermore, this study adds to the growing evidence that cones can continue to survive under non-ideal conditions.

scholarly journals Axial length and cone density as assessed with adaptive optics in myopia

2015 ◽  
Vol 63 (5) ◽  
pp. 423 ◽  
Author(s):  
Supriya Dabir ◽  
Shwetha Mangalesh ◽  
JanS A G Schouten ◽  
TosT J M Berendschot ◽  
MathewKummelil Kurian ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Axial Length ◽  
Cone Density

scholarly journals Reduced foveal cone density in early idiopathic macular telangiectasia

2021 ◽  
Vol 6 (1) ◽  
pp. e000603
Author(s):  
Hongxin Song ◽  
Ethan A Rossi ◽  
David R Williams
Keyword(s):  
Adaptive Optics ◽  
Cellular Level ◽  
Cone Photoreceptor ◽  
Cone Photoreceptors ◽  
Clinically Normal ◽  
Macular Telangiectasia ◽  
Idiopathic Macular Telangiectasia ◽  
Retinal Capillaries ◽  
Manual Correction ◽  
Cone Density

ObjectiveIdiopathic macular telangiectasia (MacTel) is considered primarily a vascular disease affecting juxtafoveal retinal capillaries. However, recent evidence suggests that neuronal changes may occur early in disease development. We used high-resolution adaptive optics retinal imaging to elucidate the foveal cone photoreceptor changes at a cellular level in patients with MacTel.Methods and analysisWe used adaptive optics scanning light ophthalmoscopy (AOSLO) to evaluate the foveal cone photoreceptors in the less-affected eye of patients with asymmetric MacTel. AOSLO images of cone photoreceptors were obtained in a 4°×4° area centred on the foveola. Individual cone positions were identified within a 2°×2° area centred on the fovea, using semiautomatic cone marking software with manual correction, permitting calculation of a map of cone density.ResultsIn all participants, one eye was affected with MacTel, the fellow eye was clinically normal or near normal, with visual acuity of 20/25 or better and subtle angiographic leakage. The foveal cone mosaics were continuous with tight packing and cones exhibited normal reflectivity. However, cone density was significantly lower for all participants (mean=80 733 cones/mm2) within 0.5° than the cone density previously reported for normal eyes.ConclusionsFoveal cone density is lower than normal in the clinically less-affected eyes of patients with asymmetric MacTel. This suggests that cone photoreceptor loss may precede classic obvious vascular changes in idiopathic MacTel.

scholarly journals Methods for investigating the local spatial anisotropy and the preferred orientation of cones in adaptive optics retinal images

2016 ◽  
Vol 33 ◽  
Author(s):  
ROBERT F. COOPER ◽  
MARCO LOMBARDO ◽  
JOSEPH CARROLL ◽  
KENNETH R. SLOAN ◽  
GIUSEPPE LOMBARDO
Keyword(s):  
Adaptive Optics ◽  
Intensity Variation ◽  
Retinal Disease ◽  
Retinal Images ◽  
Cone Photoreceptor ◽  
Good Image Quality ◽  
High Agreement ◽  
Spatial Anisotropy ◽  
Cone Mosaic ◽  
The Fourier Transform

AbstractThe ability to noninvasively image the cone photoreceptor mosaic holds significant potential as a diagnostic for retinal disease. Central to the realization of this potential is the development of sensitive metrics for characterizing the organization of the mosaic. Here we evaluated previously-described and newly-developed (Fourier- and Radon-based) methods of measuring cone orientation in simulated and real images of the parafoveal cone mosaic. The proposed algorithms correlated well across both simulated and real mosaics, suggesting that each algorithm provides an accurate description of photoreceptor orientation. Despite high agreement between algorithms, each performed differently in response to image intensity variation and cone coordinate jitter. The integration property of the Fourier transform allowed the Fourier-based method to be resistant to cone coordinate jitter and perform the most robustly of all three algorithms. Conversely, when there is good image quality but unreliable cone identification, the Radon algorithm performed best. Finally, in cases where the cone coordinate reliability was excellent, the method previously described by Pum and colleagues performed best. These descriptors are complementary to conventional descriptive metrics of the cone mosaic, such as cell density and spacing, and have the potential to aid in the detection of photoreceptor pathology.

scholarly journals Three-dimensional composition of the photoreceptor cone layers in healthy eyes using adaptive-optics optical coherence tomography (AO-OCT)

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245293
Author(s):  
Adrian Reumueller ◽  
Lorenz Wassermann ◽  
Matthias Salas ◽  
Markus Schranz ◽  
Valentin Hacker ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Adaptive Optics ◽  
Outer Segment ◽  
Three Dimensional ◽  
Optical Coherence ◽  
Cone Photoreceptors ◽  
Cone Mosaic ◽  
Automated Technique ◽  
Healthy Eyes ◽  
Cone Density

Purpose To assess the signal composition of cone photoreceptors three-dimensionally in healthy retinas using adaptive optics optical coherence tomography (AO-OCT). Methods Study population. Twenty healthy eyes of ten subjects (age 23 to 67). Procedures. After routine ophthalmological assessments, eyes were examined using AO-OCT. Three-dimensional volumes were acquired at 2.5° and 6.5° foveal eccentricity in four main meridians (superior, nasal, inferior, temporal). Cone densities and signal compositions were investigated in four different planes: the cone inner segment outer segment junction (IS/OS), the cone outer segment combined with the IS/OS (ISOS+), the cone outer segment tips (COST) and full en-face plane (FEF) combining signals from all mentioned cone layers. Additionally, reliability of a simple semi-automated approach for assessment of cone density was tested. Main outcome measures. Cone density of IS/OS, IS/OS+, COST and FEF. Qualitative depiction and composition of each cone layer. Inter-rater agreement of cone density measurements. Results Mean overall cone density at all eccentricities was highest at the FEF plane (21.160/mm2), followed by COST (20.450/mm2), IS/OS+ (19.920/mm2) and IS/OS (19.530/mm2). The different meridians and eccentricities had a significant impact on cone density, with lower eccentricity resulting in higher cone densities (p≤.001), which were highest at the nasal, then temporal, then inferior and then superior meridian. Depiction of the cone mosaic differed between all 4 layers regarding signal size and packing density. Therefore, different cone layers showed evident but not complete signal overlap. Using the semi-automated technique for counting of cone signals achieved high inter-rater reliability (ICC > .99). Conclusions In healthy individuals qualitative and quantitative changes in cone signals are found not only in different eccentricities and meridians, but also within different photoreceptor layers. The variation between cone planes has to be considered when assessing the integrity of cone photoreceptors in healthy and diseased eyes using adaptive optics technology.

scholarly journals Photoreceptor evaluation after successful macular hole closure: an adaptive optics study

2019 ◽  
Vol 11 ◽  
pp. 251584141986813 ◽  
Author(s):  
Ashish Markan ◽  
Rohan Chawla ◽  
Vinay Gupta ◽  
Manasi Tripathi ◽  
Anu Sharma ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Macular Hole ◽  
Adaptive Optics ◽  
Nearest Neighbors ◽  
Postoperative Recovery ◽  
Macular Hole Surgery ◽  
Temporal Quadrant ◽  
Better Than ◽  
Hole Closure ◽  
Cone Density

Objective: To study photoreceptor changes after a successful macular hole surgery using adaptive optics. Materials and Methods: Three patients who underwent a successful macular hole surgery were studied. Cone density, spacing, and number of nearest neighbors were analyzed at 2° and 4° of eccentricity in all four quadrants using adaptive optics. Results: All three patients gained a visual acuity better than logMAR 0.477 (Snellen equivalent 6/18) at 6 months following successful macular hole surgery. Following successful closure of the macular hole, photoreceptors were appreciated at 2° and 4° of eccentricity from the center. However, as compared with the fellow normal eye, cell density was reduced significantly in the inferior (12,929.33 ± 2047.50 versus 23,839.67 ± 3711.16 cells/mm2 at 2°) and temporal quadrant (13,890 ± 3424.26 versus 22,578.67 ± 5651.34 cells/mm2 at 2°), and intercell spacing was increased significantly in inferior (9.6 ± 0.92 versus 7.14 ± 0.545 µm) and nasal quadrant (8.83 ± 0.39 versus 7.49 ± 0.42 µm). Number of nearest neighbors was unaffected after the hole closure. Conclusion: Postoperative recovery of vision after successful closure of the hole occurs because of the migration or shifting of cells from parafoveal retina toward the center. Cells nearest to the hole margin (at 2° eccentricity) appear to shift more as compared with cells which are further away.

scholarly journals Assessment of fundus autofluorescence and adaptive optics high-resolution images in macular disorders

2021 ◽  
Author(s):  
Radu Ochinciuc ◽  
Uliana Ochinciuc ◽  
George Balta ◽  
Adrian Teodoru ◽  
Leila Al Barri ◽  
...  
Keyword(s):  
High Resolution ◽  
Adaptive Optics ◽  
Pigment Epithelium ◽  
Fundus Autofluorescence ◽  
Retinal Pigment ◽  
Subretinal Fluid ◽  
Cellular Level ◽  
Cone Mosaic ◽  
High Resolution Images ◽  
Cone Density

Abstract Purpose This study analyzed and compared the results of adaptive optics (AO) and fundus autofluorescence (FAF) in various maculopathies. Methods The study included four different types of maculopathy: central serous chorioretinopathy (CSC), retinitis pigmentosa (RP), Stargardt disease (STGD) and phototoxic retinopathy. In all four cases cone mosaic and cone density were obtained using AO fundus camera. Further the high resolution images were compared with the FAF and optical coherence tomography (OCT) results. Results In CSC, FAF and AO were able to show changes in the macula even two years after the subretinal fluid resorption, as opposed to a normal OCT. The improvement of FAF and cone mosaic appearance was concomitant with the visual acuity growth. Several cone mosaic phenotypes were observed in RP and STGD. In RP the cone density was 24.240cones/mm2 in the center, and decreased to 8.163cones/mm2 in the parafoveolar area. In STGD the cone density was lower in the center, 9.219cones/mm2, and higher at the periphery, 12.594cones/mm2. In the case of phototoxic retinopathy, AO and OCT were more effective than FAF in highlighting the photoreceptor and retinal pigment epithelium lesions. Conclusions FAF and AO are very useful tools in macular pathologies examination. FAF can give us a true picture about metabolic changes in the macula while AO allows us to view changes up to the cellular level.

scholarly journals Cone photoreceptor dysfunction in retinitis pigmentosa revealed by optoretinography

2021 ◽  
Vol 118 (47) ◽  
pp. e2107444118
Author(s):  
Ayoub Lassoued ◽  
Furu Zhang ◽  
Kazuhiro Kurokawa ◽  
Yan Liu ◽  
Marcel T. Bernucci ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Adaptive Optics ◽  
Vision Loss ◽  
Photoreceptor Cells ◽  
Segment Length ◽  
Cone Photoreceptor ◽  
Cone Cells ◽  
Common Group ◽  
Cone Density

Retinitis pigmentosa (RP) is the most common group of inherited retinal degenerative diseases, whose most debilitating phase is cone photoreceptor death. Perimetric and electroretinographic methods are the gold standards for diagnosing and monitoring RP and assessing cone function. However, these methods lack the spatial resolution and sensitivity to assess disease progression at the level of individual photoreceptor cells, where the disease originates and whose degradation causes vision loss. High-resolution retinal imaging methods permit visualization of human cone cells in vivo but have only recently achieved sufficient sensitivity to observe their function as manifested in the cone optoretinogram. By imaging with phase-sensitive adaptive optics optical coherence tomography, we identify a biomarker in the cone optoretinogram that characterizes individual cone dysfunction by stimulating cone cells with flashes of light and measuring nanometer-scale changes in their outer segments. We find that cone optoretinographic responses decrease with increasing RP severity and that even in areas where cone density appears normal, cones can respond differently than those in controls. Unexpectedly, in the most severely diseased patches examined, we find isolated cones that respond normally. Short-wavelength–sensitive cones are found to be more vulnerable to RP than medium- and long-wavelength–sensitive cones. We find that decreases in cone response and cone outer-segment length arise earlier in RP than changes in cone density but that decreases in response and length are not necessarily correlated within single cones.

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