Variations in the cone packing density with eccentricity in emmetropes

Dabir, Supriya; Mangalesh, Shwetha; Kumar, K A; Kummelil, Mathew Kurian; Roy, Abhijit Sinha; Shetty, Rohit

doi:10.1038/eye.2014.229

Cited by 18 publications

(25 citation statements)

References 9 publications

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“…We imaged the human retina of 55 healthy subjects along the nasal and temporal semi‐meridian up to 24°. Our results are in agreement with the literature concerning the central 15° . There is a sharp decrease in density up to 12° of eccentricity and then cone density did not vary so much.…”

Section: Discussionsupporting

confidence: 93%

“…cone density) came from histological measurements, which required examining post‐mortem subjects . In the past decades, several authors conducted in vivo experiments of the distribution of cones in the parafoveal region of the retina up to about 7° of eccentricity . However, up to now, few studies investigated the peripheral retinal structure.…”

Section: Introductionmentioning

confidence: 99%

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Distribution of mid‐peripheral cones in emmetropic and myopic subjects using adaptive optics flood illumination camera

Woog

Legras

2019

Ophthalmic Physiologic Optic

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Citation information: Woog K & Legras R. Distribution of mid-peripheral cones in emmetropic and myopic subjects using adaptive optics flood illumination camera. AbstractPurpose: We measured in vivo cone photoreceptors up to 24°of eccentricity along the horizontal meridian of healthy human retina. We also investigated the impact on cone densities of axial eye length elongation occurring with myopia. Methods: Using a flood illumination device coupled with an adaptive optics system, rtx1 TM , (www.imagine-eyes.com), 55 right healthy retinas were imaged along the horizontal (i.e. nasal and temporal) meridian over a 48°field (i.e. from 3°to 24°each 3°). Then, cones were manually detected within 80 9 80 pixel regions of interest. Cone density and packing geometry (i.e. number of neighbours) were calculated (AOdetect software TM ). Subjects were divided into three groups: a group of 36 emmetropic (i.e. refractive error from À0.25D to +0.50D) subjects; a group of 10 low myopic subjects (i.e. refractive error from À0.50D to À2.50D); and a group of nine high myopic subjects (i.e. >À2.50D). Results: Cone density decreased with eccentricity in both semi-meridians. The decrease in cone photoreceptors occurred mainly in the first 9°. The difference of cone density between the nasal and temporal semi-meridian increased with eccentricity from 0.6% at 3°to 26% at 24°. Average cone density of emmetropes (850 cones deg À2 or 11 087 cones mm À2 ), low myopes (830 cones deg À2 or 9731 cones mm À2 ), and high myopes (912 cones deg À2 or 9744 cones mm À2 ), suggested that the retinas of the high myopic subjects were more stretched than the low myopic subjects retinas and even more stretched than that of the emmetropes. The axial eyeball elongation (square of the ratio of the axial eye length of 9%) seems to explain the cone density (11%) difference between emmetropes and low myopes. However, while the eyeball elongation between low and high myopes is still important (i.e. 11%), cone density difference between both populations was negligible (i.e. 3%). The ratio of cone density varied from À17% to 22% as a function of eccentricity involving that the retinal stretching is not uniform along the horizontal meridian. Conclusion: The difference of cone density (i.e. cone mm À2 ) between groups supports the hypothesis that the retina is stretched with the eyeball elongation. However, this elongation does not seem to be uniform along the horizontal meridian favouring the hypothesis of a local elongation of the retina.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Distribution of mid‐peripheral cones in emmetropic and myopic subjects using adaptive optics flood illumination camera

Woog

Legras

2019

Ophthalmic Physiologic Optic

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“…We did not assess the CD within 400 lm of the foveal center due to the limit of resolution of the rtx1 systems. [29][30][31][32] The regional sampling method was previously described. 33 The area within an annulus of 0.4-to 2.4-mm diameter was defined as the total annular zone (TAZ) in a 3 3 3mm area ( Fig.…”

Section: Regional Analysismentioning

confidence: 99%

Relationship Between Cone Loss and Microvasculature Change in Retinitis Pigmentosa

Lin

Shen

Pan

et al. 2019

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. To objectively quantify cone density (CD) and microvascular density (MVD) in normal subjects and patients with moderate or severe retinitis pigmentosa (RP) by adaptive optics (AO) and optical coherence tomography angiography (OCTA) and to evaluate the changes in the parafoveal regions. METHOD. Thirty-seven eyes from 20 RP patients and 54 eyes from 29 age-matched healthy participants underwent AO fundus and OCTA imaging. AO images covering a 3-mm-diameter area centered on the fovea were subdivided into 5 equidistant concentric rings (C1-C5). An automated algorithm was used to quantify the mean cone density (mCD; cells/mm 2). Macular MVDs (%) in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were assessed by OCTA. RESULTS. In the moderate RP group, CDs in C2 and C3 were each significantly lower than in the normal group (both P < 0.05). In the severe RP group, CDs were significantly lower than in normal eyes in each concentric ring (all P < 0.001; C1-C5). In both RP groups, MVDs were significantly lower than in normal eyes for both the SCP and DCP (both P < 0.05). The mean CD was significantly correlated with the MVD in the DCP (r ¼ 0.43; P ¼ 0.028) but not in the SCP (r ¼ À0.19, P ¼ 0.323). CONCLUSIONS. Decreased CD was present in the moderate and severe RP groups. This was accompanied by a decreased MVD in the DCP. Direct assessment of photoreceptors in RP patients by high-resolution imaging technologies is crucial for the future development of RP therapeutics.

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“…The average foveal cone count in normal Asian eyes from our institute was 24 000 cones per mm 2 . 18 The detailed list of cone count including fovea and para fovea are presented in Table 2.…”

Section: Ao Imagingmentioning

confidence: 99%

Adaptive optics imaging of the outer retinal tubules in Bietti’s crystalline dystrophy

Battu

Akkali

Bhanushali

et al. 2016

Eye

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Variations in the cone packing density with eccentricity in emmetropes

Cited by 18 publications

References 9 publications

Distribution of mid‐peripheral cones in emmetropic and myopic subjects using adaptive optics flood illumination camera

Distribution of mid‐peripheral cones in emmetropic and myopic subjects using adaptive optics flood illumination camera

Relationship Between Cone Loss and Microvasculature Change in Retinitis Pigmentosa

Adaptive optics imaging of the outer retinal tubules in Bietti’s crystalline dystrophy

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