Reflectance Decreases before Thickness Changes in the Retinal Nerve Fiber Layer in Glaucomatous Retinas

Huang, Xiang; Zhou, Yedi; Kong, Weina; Knighton, Robert W.

doi:10.1167/iovs.11-7665

Cited by 73 publications

(77 citation statements)

References 19 publications

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“…Recent studies have shown that a decrease in RNFL reflectance occurs prior to thinning of the RNFL [5][6][7][8][9][10][11], and suggest that direct OCT measurement of RNFL reflectance may provide a powerful new method for the early detection of glaucoma. Although directional reflectance is a major source of variability for RNFL reflectance measurements [24][25][26], none of the in vivo studies took this into account.…”

Section: Discussionmentioning

confidence: 99%

“…For instance, Optical Coherence Tomography (OCT), which is widely used in clinical diagnosis of glaucoma, measures RNFL thickness by identifying the RNFL as a highly reflective layer under the retinal surface, with change of thickness used as a biomarker for axonal damage [1][2][3][4]. Recent studies of glaucomatous retinas reveal that a decrease of RNFL reflectance occurs prior to thinning of the RNFL [5][6][7][8][9][10][11]. Glaucoma damages retinal ganglion cells (RGC) and their axons [12][13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…Supporting this idea, depolymerization of axonal microtubules (MTs) decreases RNFL reflectance [21][22][23]. Further, our recent in vitro study in hypertensive retinas shows that change of RNFL reflectance associates with axonal cytoskeletal alteration [7]. Because RNFL reflectance appears to be more sensitive to glaucomatous damage than change of RNFL thickness, direct measurements of RNFL reflectance hold promise as a method for the early detection of glaucoma.…”

Section: Introductionmentioning

confidence: 99%

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Retinal nerve fiber layer reflectometry must consider directional reflectance

Huang¹,

Knighton²,

Feuer³

et al. 2015

Biomed. Opt. Express

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Recent studies reveal that measurements of retinal nerve fiber layer (RNFL) reflectance provide more sensitive detection of glaucomatous damage than RNFL thickness, but most do not consider directional reflectance of the RNFL, an important source of variability. This study quantitatively compared RNFL directional reflectance, represented by an angular spread function (ASF), measured at different scattering angles, different wavelengths and different distances from the optic nerve head (ONH) and for bundles with different thicknesses (T). An ASF was characterized by its amplitude (A) and width (W). Internal reflectance of a bundle was expressed as A/T. The study found that A varied significantly with scattering angle and wavelength and that A/T was different among bundles but constant along the same bundle, indicating that the internal structure of axons may vary among bundles but does not change with distance. This study also found that W was larger near the ONH and at longer wavelengths, but did not depend on scattering angle or T. Because a 4.3° change in incident angle can change reflected intensity by a factor of 2.7, accounting for directional reflectance should improve the accuracy and reproducibility of RNFL reflectance measurements.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Retinal nerve fiber layer reflectometry must consider directional reflectance

Huang¹,

Knighton²,

Feuer³

et al. 2015

Biomed. Opt. Express

Self Cite

View full text Add to dashboard Cite

show abstract

“…[15][16][17][18]32,33 Despite this, these patients would be considered to have early to moderate glaucomatous damage by their visual field state (median MD: À 3.6 dB) where changes are often considered to be more easily detected. Evidence is also emerging that in experimental glaucoma, changes in RNFL retardance 40,41 and reflectance 42 can precede changes in RNFLT, and this may explain a slower rate of SLP-measured RNFLT change in these patients. The large, but not statistically significant, difference between patients and controls in OCT-measured rates of RNFLT change was due in part to the substantial, positive rate of RNFLT change in control subjects.…”

Section: Discussionmentioning

confidence: 99%

Rates of retinal nerve fibre layer thickness change in glaucoma patients and control subjects

O’Leary

Artes

Hutchison

et al. 2012

Eye

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Purpose To examine the rates of retinal nerve fibre layer thickness (RNFLT) change in glaucoma patients and healthy, age-similar control subjects with three techniques: scanning laser polarimetry with variable corneal compensation (VCC) and enhanced corneal compensation (ECC), and timedomain optical coherence tomography (OCT). Methods Sixty-one patients and thirty-three controls were examined with each technique and with standard automated perimetry (SAP) every 6 months. Rates of global RNFLT change and SAP mean deviation (MD) change were estimated with linear mixedeffects models. Results The median (interquartile range) baseline age was 64.4 (58.2, 71.0) years for patients and 62.4 (56.3, 70.1) years for controls (P ¼ 0.56). There was a median of seven examinations over 3.1 years for patients and six examinations in 3.0 years for controls. Baseline visual field MD and RNFLT for all imaging modalities were significantly lower (Po0.01) in patients compared with controls. Rates of RNFLT change were not significantly different between patients and controls (PZ0.19). Mean rates of VCC-measured RNFLT change were À 0.18 and À 0.37 lm per year in patients and controls, whereas the respective figures for ECC and OCT were À 0.13 and À 0.31 lm per year, and 0.04 and 0.61 lm per year. Mean rates of MD change were À 0.20 and 0.03 dB per year in patients and controls, respectively (P ¼ 0.01). Conclusion Rates of RNFLT change in glaucoma patients were not statistically different from control subjects for any modality. A significantly negative rate of MD change in patients suggests a genuine, continued deterioration in these patients not reflected by RNFLT changes.

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“…While OCT at 800 nm and 1050 nm enables excellent tissue architectural contrast, visible light is more sensitive to absorption from chromophores such as photopigment, melanin, and hemoglobin, as well as scattering from subcellular structures [14], all of which are potential retinal disease biomarkers. Recently, intense and broadband supercontinuum (SC) light sources have made it possible to perform OCT in the visible wavelength regime [9,15].…”

Section: Introductionmentioning

confidence: 99%

Structural and functional human retinal imaging with a fiber-based visible light OCT ophthalmoscope

Chong

Bernucci

Radhakrishnan

et al. 2016

Biomed. Opt. Express

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Abstract:The design of a multi-functional fiber-based Optical Coherence Tomography (OCT) system for human retinal imaging with < 2 micron axial resolution in tissue is described. A detailed noise characterization of two supercontinuum light sources with different pulse repetition rates is presented. The higher repetition rate and lower noise source is found to enable a sensitivity of 96 dB with 0.15 mW light power at the cornea and a 98 microsecond exposure time. Using a broadband (560 ± 50 nm), 90/10, fused single-mode fiber coupler designed for visible wavelengths, the sample arm is integrated into an ophthalmoscope platform, similar to current clinical OCT systems. To demonstrate the instrument s range of operation, in vivo structural retinal imaging is also shown at 0.15 mW exposure with 10,000 and 70,000 axial scans per second (the latter comparable to commercial OCT systems), and at 0.03 mW exposure and 10,000 axial scans per second (below maximum permissible continuous exposure levels). Lastly, in vivo spectroscopic imaging of anatomy, saturation, and hemoglobin content in the human retina is also demonstrated.

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Reflectance Decreases before Thickness Changes in the Retinal Nerve Fiber Layer in Glaucomatous Retinas

Abstract: Elevation of intraocular pressure causes decrease in RNFL reflectance for bundles near the ONH. Change in RNFL reflectance precedes thinning of the RNFL. The results suggest that a decrease in RNFL reflectance near the ONH is an early sign of glaucomatous damage.

Cited by 73 publications

References 19 publications

Retinal nerve fiber layer reflectometry must consider directional reflectance

Retinal nerve fiber layer reflectometry must consider directional reflectance

Rates of retinal nerve fibre layer thickness change in glaucoma patients and control subjects

Structural and functional human retinal imaging with a fiber-based visible light OCT ophthalmoscope

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