Reliability of cone counts using an adaptive optics retinal camera

Garnier, M Bidaut; Flores, Mathieu; Debellemanière, Guillaume; Puyraveau, Marc; Tumahai, Perle; mathieu, meillat; Schwartz, C.; Montard, M; Delbosc, B.; Saleh, Maher

doi:10.1111/ceo.12356

Cited by 36 publications

(21 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This recently detailed counting method (Bidaut Garnier et al. ) provides good reproducibility of measurements in normal volunteers in the same examination conditions. Cone spacing and the percentage of cones with six neighbours (nearest neighbour analysis) assessed on the Voronoi index were also analysed in the same area.…”

Section: Methodsmentioning

confidence: 99%

Assessment of parafoveal cone density in patients taking hydroxychloroquine in the absence of clinically documented retinal toxicity

Debellemanière

Flores

Tumahai

et al. 2015

Acta Ophthalmologica

Self Cite

View full text Add to dashboard Cite

ABSTRACT.Purpose: To measure cone density in patients taking hydroxychloroquine (HCQ), with no clinical evidence of maculopathy. Methods: Patients visiting for HCQ macular toxicity screening in the Besanc ßon University Hospital Ophthalmology Department (France) were studied. They underwent routine examination including spectral-domain optical coherence tomography, fundus autofluorescence and multifocal electroretinogram to detect HCQ-induced retinal toxicity. Cone metrics (density, spacing and percentage of cones with six neighbours) were obtained using an adaptive optics camera (RTX1, Imagine Eyes, Orsay, France). The region of interest corresponded to a 0.3°3 0.3°s quare placed nasally and temporally at 2°of eccentricity from the fovea. Results: Forty eyes of 23 patients were studied. The majority of the patients (21/ 23) were female. They were aged from 25 to 60 years (mean age AE SD: 40.1 years AE 10). The cumulative dose for HCQ ranged from 24 to 2160 g (777 AE 558 g). None of them displayed HCQ toxicity on screening tests. Bivariate analysis showed moderate cone loss with escalating doses of HCQ (linear regression, r² = 0.23, p = 0.018). Cone spacing also increased with increasing cumulative dose (r² = 0.17, p = 0.008). Cone packing remained unchanged (p > 0.05). Multivariate analysis showed that age and cumulative dose were additive and independent factors of cone dropout. Conclusions: In this pilot study, we observed moderate cone loss as HCQ cumulative doses increased. The early detection of parafoveal cone metric changes may represent the earliest sign of HCQ macular toxicity during screening.

show abstract

Section: Methodsmentioning

confidence: 99%

Assessment of parafoveal cone density in patients taking hydroxychloroquine in the absence of clinically documented retinal toxicity

Debellemanière

Flores

Tumahai

et al. 2015

Acta Ophthalmologica

Self Cite

View full text Add to dashboard Cite

show abstract

“…The image resolution achieved by this technology is by far superior (S) to that of any other known diagnostic tool. [5,6] …”

Section: Introductionmentioning

confidence: 99%

“…Changes in the transparency of the cornea, lens, and vitreous may prevent acquisition of sharp images. [5,8] The advantages of the device are that it enables selection of any area of the retina for imaging and repeating of measurements in the same spot based on automatically saved coordinates of that spot in the form of an entire image. The rtx1 is particularly valuable for evaluating the progression of retinal changes.…”

Section: Introductionmentioning

confidence: 99%

Human photoreceptor cone density measured with adaptive optics technology (rtx1 device) in healthy eyes

et al. 2017

View full text Add to dashboard Cite

The anatomic structures of the anterior segment of the eye enable correct reception of stimuli by the retina, which contains receptors that receive light impulses and transmit them to the visual cortex. The aim of this study was to assess the effect of the size of the sampling window in an adaptive optics (AO) flood-illumination retinal camera (rtx1) on cone density measurements in the eyes of healthy individuals and to investigate the differences in cone density and spacing in different quadrants of the retina. Thirty-three subjects with no ophthalmic or systemic disease underwent a detailed ophthalmologic examination. Photographs of retinal fragments 3 degrees from the fovea were taken using the rtx1 AO retinal camera. We used sampling windows with 3 sizes (50 × 50, 100 × 100, and 250 × 250 μm). Cone density, spacing, and shape were determined using AOdetect software. The median (interquartile range) cone density was 19,269 (4964) cones/mm2. There were statistically significant differences between measurements taken with the 50/50 and 250/250-m windows. There were no significant differences in the cone spacing results between any of the windows examined, but the measurements differed according to location between the superior and temporal quadrants. The most common cone shape was hexagonal (47.6%) for all window sizes and locations. These findings may help in the development of a normative database for variation in cone density in healthy subjects and to allow the best window to be chosen for obtain the most correct values for eccentricity measurements of 3 degrees. In our study, the optimal sampling window was 100 × 100 μm.

show abstract

“…Using this device and its in‐built image analysis software, Bidaut‐Garnier et al . (in this issue of CEO ) provide an initial characterization, in normal patients, of the variability in parafoveal cone density measurement . This exercise is an important step towards mainstream utilization of such instruments: as this report shows, obtaining high‐resolution images is only the beginning.…”

mentioning

confidence: 97%

“…As described in Bidaut‐Garnier et al. 's report, research studies have already begun documenting cone statistics in retinal degenerations, including age‐related macular degeneration and idiopathic macular telangiectasia, and in surgical macular disease. Likely early clinical roles for commercial AO machines will include documentation of progression of retinal degenerations, as well as diagnostic studies in diseases such as acute zonal occult outer retinopathy and plaquenil toxicity.…”

mentioning

confidence: 99%

Careful cone counting critical for clinical care

Metha

Symons

2014

Clinical Exper Ophthalmology

View full text Add to dashboard Cite

Reliability of cone counts using an adaptive optics retinal camera

Abstract: Overall, the test-retest variability of RTx-1 and its software was good in normal human eyes. Further studies in the normal clinical setting are mandatory.

Cited by 36 publications

References 33 publications

Assessment of parafoveal cone density in patients taking hydroxychloroquine in the absence of clinically documented retinal toxicity

Assessment of parafoveal cone density in patients taking hydroxychloroquine in the absence of clinically documented retinal toxicity

Human photoreceptor cone density measured with adaptive optics technology (rtx1 device) in healthy eyes

Careful cone counting critical for clinical care

Contact Info

Product

Resources

About