Retinal nerve fiber layer thickness in glaucomatous Nepalese eyes and its relation with visual field sensitivity

Khanal, Safal; Thapa, Madhu; Racette, Lyne; Johnson, Richard D.; Davey, Pinakin Gunvant; Joshi, Mahesh Raj

doi:10.1016/j.optom.2014.05.002

Cited by 12 publications

(15 citation statements)

References 24 publications

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“…cSLO instruments, such as the Heidelberg Retina Tomography III (HRT III; Heidelberg Engineering, Heidelberg, Germany) instrument, incorporate a point laser light source which scans the retina and a confocal pinhole aperture that acts to minimise scattered and reflected light outside the image focal-plane dramatically increasing lateral resolution (10 µm) versus fundus photography and enabling retinal topographic imaging. cSLO has proven to be a useful and versatile tool for the assessment of geographic atrophy [158], epiretinal membrane characteristics [149], drusen deposits [159], fluorescein/indocyanine green angiography [89], RPE [28], retinal nerve fibre layer thickness, and optic nerve head morphology [95]. Despite the wide-range of applications for which cSLO imaging is used, this technique has several well-documented limitations, including impaired imaging in the presence of lens and corneal opacities, small pupils, and limited axial resolution (300 µm) [42].…”

Section: Techniques For Monitoring Retinal Ganglion Cell Healthmentioning

confidence: 99%

Glaucoma: the retina and beyond

Davis¹,

Crawley

Pahlitzsch³

et al. 2016

Acta Neuropathol

234

151

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Over 60 million people worldwide are diagnosed with glaucomatous optic neuropathy, which is estimated to be responsible for 8.4 million cases of irreversible blindness globally. Glaucoma is associated with characteristic damage to the optic nerve and patterns of visual field loss which principally involves the loss of retinal ganglion cells (RGCs). At present, intraocular pressure (IOP) presents the only modifiable risk factor for glaucoma, although RGC and vision loss can continue in patients despite well-controlled IOP. This, coupled with the present inability to diagnose glaucoma until relatively late in the disease process, has led to intense investigations towards the development of novel techniques for the early diagnosis of disease. This review outlines our current understanding of the potential mechanisms underlying RGC and axonal loss in glaucoma. Similarities between glaucoma and other neurodegenerative diseases of the central nervous system are drawn before an overview of recent developments in techniques for monitoring RGC health is provided, including recent progress towards the development of RGC specific contrast agents. The review concludes by discussing techniques to assess glaucomatous changes in the brain using MRI and the clinical relevance of glaucomatous-associated changes in the visual centres of the brain.

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Section: Techniques For Monitoring Retinal Ganglion Cell Healthmentioning

confidence: 99%

Glaucoma: the retina and beyond

Davis¹,

Crawley

Pahlitzsch³

et al. 2016

Acta Neuropathol

234

151

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“…Furthermore, although a decrease in RNFL and macular thicknesses has been reported in glaucomatous eyes, there is a paucity of data on the discriminating capability of these parameters between NTG and POAG. We have previously established normative data on RNFL thickness in our population and also highlighted the relation between RNFL thickness and visual field sensitivity along with the significant potential of intraeye macular thickness asymmetry for the discrimination of NTG and POAG . In this study, we aimed to establish the distinction in these parameters between NTG and POAG to provide a new dimension to the diagnosis and management of these entities.…”

mentioning

confidence: 97%

“…Optical coherence tomography, first described by Huang and colleagues, is a new technique for real‐time, quantitative, objective, high‐resolution measurements and cross‐section imaging of the retina, from which the RNFL and macular parameters are calculated. Studies have consistently shown that both peripapillary RNFL (pRNFL) and macular thickness are lower in glaucomatous eyes . Macular thickness evaluation has received increasing attention after Zeimer and colleagues hypothesized that quantitative detection of glaucomatous damage at the posterior pole by retinal thickness mapping may provide a method for detecting and monitoring early glaucomatous damage.…”

mentioning

confidence: 99%

“…Studies have consistently shown that both peripapillary RNFL (pRNFL) and macular thickness are lower in glaucomatous eyes. [13][14][15][16] Macular thickness evaluation has received increasing attention after Zeimer and colleagues 17 hypothesized that quantitative detection of glaucomatous damage at the posterior pole by retinal thickness mapping may provide a method for detecting and monitoring early glaucomatous damage. Reports have suggested that macular thickness assessment could be a valuable surrogate measure for evaluating glaucomatous structural changes because such damage occurs in retinal ganglion cells which are multilayered and more dense in the macular region; however, there have been contrasting reports on the discriminating power and reproducibility of macular parameters, when compared to pRNFL parameters in glaucoma.…”

mentioning

confidence: 99%

“…We have previously established normative data on RNFL thickness in our population and also highlighted the relation between RNFL thickness and visual field sensitivity along with the significant potential of intraeye macular thickness asymmetry for the discrimination of NTG and POAG. 16,21,22 In this study, we aimed to establish the distinction in these parameters between NTG and POAG to provide a new dimension to the diagnosis and management of these entities. This could further contribute to early detection, prior to the observance of functional defects on the subjective tests.…”

mentioning

confidence: 99%

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Comparison of retinal nerve fiber layer and macular thickness for discriminating primary open‐angle glaucoma and normal‐tension glaucoma using optical coherence tomography

Khanal

Davey

Racette

et al. 2016

Clinical and Experimental Optometry

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Purpose The aim of this study was to evaluate the discrimination capabilities of macular and peripapillary retinal nerve fiber layer (pRNFL) thickness parameters as measured using spectral domain optical coherence tomography (SD‐OCT) between primary open‐angle glaucoma (POAG) and normal‐tension glaucoma (NTG). Methods A total of 90 subjects were enrolled: 30 healthy subjects, 30 subjects with POAG and 30 subjects with NTG, consecutively. Retinal nerve fiber layer thickness, macular thickness and volume measurements were obtained with circular and radial SD‐OCT scans. All parameters were compared between groups using an analysis of variance test. Areas under receiver‐operating characteristic (AROC) curves with sensitivities at specificities greater than or equal to 90 per cent were generated to compare discrimination capabilities of various parameters between POAG and NTG. Results Macular thickness and volume measurements were the highest in normal subjects, followed by NTG and POAG (p < 0.05). Average retinal nerve fiber layer thickness had perfect discrimination for normal‐POAG (AROC: 1.000; sensitivity: 100 per cent) and near perfect discrimination for normal‐NTG (AROC: 0.979; sensitivity: 93 per cent) as well as NTG‐POAG pairs (AROC: 0.900; sensitivity: 60 per cent). Inferior outer macular thickness (IOMT) and total volume were the best macular thickness and volume parameters having similar AROCs and sensitivities between normal and POAG (IOMT, AROC: 0.987; sensitivity: 92 per cent and total volume, AROC: 0.997; sensitivity: 97 per cent), normal and NTG (IOMT, AROC: 0.862, sensitivity: 47 per cent and total volume, AROC: 0.898, sensitivity: 67 per cent) and also between NTG and POAG (IOMT, AROC: 0.910, sensitivity: 53 per cent and total volume, AROC: 0.922, sensitivity: 77 per cent). In each comparison group, there was no statistically significant difference in AROCs between average retinal nerve fiber layer and inferior outer macular thickness, as well as total volume. Conclusions The macular parameters offer comparable performance to pRNFL parameters for the discrimination of NTG and POAG. Average retinal nerve fiber layer thickness, total macular volume and inferior outer macular thickness were the best SD‐OCT parameters with superior discriminating capabilities.

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Intraeye retinal nerve fiber layer and macular thickness asymmetry measurements for the discrimination of primary open-angle glaucoma and normal tension glaucoma

Khanal

Davey

Racette

et al. 2016

Journal of Optometry

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PurposeThe aim of this study was to evaluate the diagnostic capability of intraeye retinal nerve fiber layer (RNFL) thickness and macular thickness (MT) asymmetry measurements for the discrimination of normal tension glaucoma (NTG) and primary open-angle glaucoma (POAG) using spectral domain optical coherence tomography (SD-OCT).MethodsA total of 90 subjects were enrolled including 30 consecutive healthy subjects, 30 consecutive subjects with POAG, and 30 consecutive subjects with NTG. RNFL thicknesses around the optic disc as well as MT measurements were taken with circular and radial SD-OCT scans. Intraeye retinal and MT asymmetry were calculated as the absolute difference between superior and inferior hemispheres of the eye using posterior pole asymmetry analysis protocol. Analysis of variance was used for comparison and areas under the receiver operating characteristic (AROC) were obtained for different parameters among the three diagnostic groups.ResultsThere was a significant difference in MT asymmetry for all comparison groups (normal-NTG, p < 0.05; normal-POAG, p < 0.001; and NTG-POAG, p < 0.001). Intraeye retinal nerve fiber thickness asymmetry measurements were not different between the groups (normal-NTG, p < 0.187; normal-POAG, p < 0.056; and NTG-POAG, p < 0.837). The area under ROC curves exceeded 0.800 for all the studied parameters, including the MT asymmetry except for intraeye RNFL thickness asymmetry which had the lowest AROC as well as the least sensitivity for identifying subjects with NTG from normal (AROC = 0.626, sensitivity = 30%); POAG from normal (AROC = 0.644, sensitivity = 37%) and NTG from POAG (AROC = 0.533, sensitivity = 13%).ConclusionThe intraeye MT asymmetry holds significant potential as a distinguishing parameter for NTG and POAG.

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Retinal nerve fiber layer thickness in glaucomatous Nepalese eyes and its relation with visual field sensitivity

Abstract: The RNFL thickness measurements with SD-OCT are lower in glaucomatous eyes as compared to age-matched GS and normal eyes in the Nepalese population. A high resolution SD-OCT could aid significantly in the early diagnosis of glaucoma in Nepal.

Cited by 12 publications

References 24 publications

Glaucoma: the retina and beyond

Glaucoma: the retina and beyond

Comparison of retinal nerve fiber layer and macular thickness for discriminating primary open‐angle glaucoma and normal‐tension glaucoma using optical coherence tomography

Intraeye retinal nerve fiber layer and macular thickness asymmetry measurements for the discrimination of primary open-angle glaucoma and normal tension glaucoma

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