Glaucomatous Retinal Nerve Fiber Layer Research Articles

Rates of retinal nerve fiber layer loss in early-stage pseudoexfoliation and primary open-angle glaucoma patients using optical coherence tomography.

To characterize glaucoma progression in early-stage patients with retinal nerve fiber layer (RNFL) using the change analysis software (CAS), which was utilized to track RNFL thinning. We retrospectively analyzed 92 eyes of 92 patients with early-stage glaucoma. Patients were divided into two subgroups based on their diagnosis of pseudoexfoliation glaucoma (PEG) and primary open-angle glaucoma (POAG). A complete ophthalmologic examination was performed on all patients. Additionally, automated perimetry was conducted on each patient. Furthermore, Fourier-domain optical coherence tomography (OCT) was employed to measure RNFL and central corneal thickness. Using the OCT device's CAS, we computed the annual rate of total and glaucomatous RNFL thinning for each patient. A total of 44 PEG and 48 POAG patients were included in the study. The right eye measurements of these patients were analyzed and compared. The two groups were not significantly different in age, gender, and the number of visits per year (p > 0.05, for each). However, the difference between the mean RNFL thickness at baseline (91.39 ± 10.71 and 96.9 ± 8.6µm) and at the last visit (85.2 ± 15.76µm and 91.56 ± 9.58µm) was statistically significant between the two groups (p = 0.043, p = 0.039, respectively). Additionally, the difference in annual RNFL thinning rates (1.43 ± 0.81µm and 1.07 ± 0.32µm) between the two groups was statistically significant (p = 0.009). The annual rate of glaucomatous RNFL loss in early-stage PEG patients (1.23µm) was higher than in POAG patients (0.87µm). However, despite these loss rates, scotoma was not detected in the visual field tests of these patients. Therefore, using CAS in the follow-up of early-stage glaucoma patients is a useful alternative for monitoring glaucomatous progression. Furthermore, this method can be utilized in future research for the diagnosis and follow-up of glaucoma in special populations (e.g., those with pathological myopia or high hyperopia) that are not included in normative databases.

The Impact of Achieving Target Intraocular Pressure on Glaucomatous Retinal Nerve Fiber Layer Thinning in a Treated Clinical Population

To estimate the effect of being below and above the clinician-set target intraocular pressure (IOP) on rates of glaucomatous retinal nerve fiber layer (RNFL) thinning in a treated real-world clinical population. Retrospective cohort study. A total of 3256 eyes (1923 patients) with ≥5 reliable optical coherence tomography scans and 1 baseline visual field test were included. Linear mixed-effects modeling estimated the effects of the primary independent variables (mean target difference [measured IOP - target IOP] and mean IOP, mm Hg) on the primary dependent variable (RNFL slope, µm/y) while accounting for additional confounding variables (age, biological sex, race, baseline RNFL, baseline pachymetry, and disease severity). A spline term accounted for differential effects when above (target difference >0 mm Hg) and below (target difference ≤0 mm Hg) target pressure. Eyes below and above target had significantly different mean RNFL slopes (-0.44 vs -0.71 µm/y, P < .001). Each 1 mm Hg increase above target had a 0.143 µm/y faster rate of RNFL thinning (P < .001). Separating by disease severity, suspect, mild, moderate, and advanced glaucoma had 0.135 (P = .002), 0.116 (P = .009), 0.203 (P = .02), and 0.65 (P = .22) µm/y faster rates of RNFL thinning per 1 mm Hg increase, respectively. Being above the clinician-set target pressure is associated with more rapid RNFL thinning in suspect, mild, and moderate glaucoma. Faster rates of thinning were also present in advanced glaucoma, but statistical significance was limited by the lower sample size of eyes above target and the optical coherence tomography floor effect.

Deep Optic Nerve Head Morphology in Tilted Disc Syndrome and Its Clinical Implication on Visual Damage.

To study deep optic nerve head (ONH) morphology in tilted disc syndrome (TDS) and identify factors associated with retinal nerve fiber layer (RNFL) defect. In patients with TDS, we evaluated the optic disc shape using the Bruch's membrane opening (BMO)-anterior scleral canal opening (ASCO) offset and measured the border tissue (BT) length, depth, and angle in the direction of the tilt, using radial ONH optical coherence tomography (OCT). We compared the parameters between the TDS groups with and without RNFL defects. Twenty-one eyes had no glaucomatous RNFL defect, and 38 eyes had a glaucomatous RNFL defect. The group with RNFL defects had a higher baseline IOP, larger tilt axis of BMO-ASCO optic disc margin (76.4° ± 14.5° vs. 87.9° ± 15.4°, P = 0.012), larger BMO-lamina cribrosa insertion (LCI) angle (25.6° ± 9.3° vs. 43.6° ± 15.2°, P < 0.001), and more lamina cribrosa (LC) defects (4.3% vs. 30.6%, P = 0.028) than without RNFL defects. The tilt axis and BMO-LCI angle were significant factors after adjusting for baseline IOP and LC defect. The BMO-LCI angle had excellent diagnostic power for glaucomatous RNFL defect in TDS, similar to the visual field mean deviation. OCT-based large deep ONH BT angle and tilt axis were factors associated with the presence of RNFL defects in TDS. The results suggest a mechanism of RNFL defect associated with structural ONH deformation. Further investigations are warranted to understand the role of ONH structures in a general population with and without optic disc tilt.

Development of a deep learning system to detect glaucoma using macular vertical optical coherence tomography scans of myopic eyes

Myopia is one of the risk factors for glaucoma, making accurate diagnosis of glaucoma in myopic eyes particularly important. However, diagnosis of glaucoma in myopic eyes is challenging due to the frequent associations of distorted optic disc and distorted parapapillary and macular structures. Macular vertical scan has been suggested as a useful tool to detect glaucomatous retinal nerve fiber layer loss even in highly myopic eyes. The present study was performed to develop and validate a deep learning (DL) system to detect glaucoma in myopic eyes using macular vertical optical coherence tomography (OCT) scans and compare its diagnostic power with that of circumpapillary OCT scans. The study included a training set of 1416 eyes, a validation set of 471 eyes, a test set of 471 eyes, and an external test set of 249 eyes. The ability to diagnose glaucoma in eyes with large myopic parapapillary atrophy was greater with the vertical than the circumpapillary OCT scans, with areas under the receiver operating characteristic curves of 0.976 and 0.914, respectively. These findings suggest that DL artificial intelligence based on macular vertical scans may be a promising tool for diagnosis of glaucoma in myopic eyes.

Multicolor imaging compared with red-free fundus photography in the detection of glaucomatous retinal nerve fiber layer thinning

BackgroundTo compare the ability of multicolor imaging (MCI) with red-free fundus photography (RFP) to detect glaucomatous retinal nerve fiber layer (RNFL) thinning. MethodsA total of 127 eyes of 79 patients with glaucoma underwent MCI using blue light, RFP, and circumpapillary optical coherence tomography (OCT) scanning on the same day. Angular location and width of the RNFL defects (RNFLDs) identified on the MCI and RFP were independently measured, and compared with those of RNFL thinning indicated by abnormal color codes on OCT. ResultsThe angular location and width of the RNFLDs determined by both MCI and RFP were well correlated with those of RNFL thinning determined by OCT (all P ≤ 0.013). The correlation of angular width with OCT was significantly stronger for MCI than for RFP (R = 0.708 vs. R = 0.616, P = 0.009). The superiority of MCI to RFP in the detection of OCT-determined RNFL thinning was significant in the inferior (P = 0.025) and marginally significant in the superior (P = 0.084) hemisectors. Thinner RNFL and longer axial length were significantly associated with better visualization of RNFLD by MCI than by RFP, respectively in the superior (OR = 0.948, P = 0.048) and inferior (OR = 1.490, P = 0.012) hemisectors. ConclusionsRNFLD on MCI correlated well with OCT measurement of RNFL thinning in eyes with glaucoma. MCI performed better than conventional RFP in the detection of OCT-determined RNFL thinning, specifically in eyes with thinner RNFL and those with myopia. MCI may be more useful than conventional RFP in evaluating glaucomatous RNFL thinning.

Progression of Glaucoma in Highly Myopic Eyes with Paravascular Inner Retinal Defects

Purpose: To report a case of glaucoma progression in highly myopic eyes with paravascular inner retinal defects.Case summary: Retinal nerve fiber layer (RNFL) defects with cleavage-like irregular margins and internal areas were found around the retinal vessels in highly myopic eyes of a 17-year-old female. On suspicion of paravascular inner retinal defect (PIRD) instead of glaucomatous RNFL defect, observation without treatment was recommended. After 10 years of follow-up, RNFL defects and neuroretinal rim thinning were found around the pre-existing PIRD on fundus photographs. Optical coherence tomography also revealed decreased RNFL thickness.Conclusions: Glaucomatous changes progressed around the pre-existing PIRD area over the 10-year follow-up. This indicates the need for caution when assessing glaucoma in highly myopic eyes with PIRD.

Multicolor Imaging for Detection of Retinal Nerve Fiber Layer Defect in Myopic Eyes With Glaucoma

To investigate the diagnostic performance of multicolor imaging for detection of retinal nerve fiber layer (RNFL) defects in myopic eyes with glaucoma. Comparative diagnostic analysis. A total of 150 myopic eyes of 138 patients (< -1.00 diopter or axial length >24 mm) underwent multicolor imaging by Spectralis (Heidelberg Engineering GmbH) optical coherence tomography (OCT). Two independent observers graded the RNFL visibility score and determined the location of the RNFL defect on each image. Readings were taken from the superior and inferior areas. The diagnostic performances of multicolor, green-reflectance, and blue-reflectance images for detection of the RNFL defect were compared with those of conventional fundus and red-free RNFL photographs. The interobserver agreement on the RNFL visibility score was substantial for fundus and RNFL photographs and multicolor and green-reflectance images and was perfect for blue-reflectance images. The interobserver agreement on the location of the RNFL defect was better when using multicolor imaging than when using conventional photography. The green-reflectance image (2.89 ± 0.31) showed the highest RNFL visibility score, followed by blue-reflectance (2.88 ± 0.32) and multicolor (2.57 ± 0.63) images. The sensitivity of multicolor imaging (94.9%, 93.2%, and 91.5% for green-reflectance, blue-reflectance, and multicolor images, respectively) was significantly higher than that of fundus photography (83.1%) for detection of superotemporal RNFL defects (all P < .05). It was significantly higher for inferotemporal defects than those of fundus and RNFL photographs (all P < .05). Multicolor imaging can visualize the glaucomatous RNFL defects in myopic eyes that are indistinguishable on conventional photography.

The Effect of Age on Increasing Susceptibility to Retinal Nerve Fiber Layer Loss in Glaucoma.

PurposeTo determine whether aging modifies the effect of intraocular pressure (IOP) on progressive glaucomatous retinal nerve fiber layer (RNFL) thinning over time.MethodsThis was a retrospective cohort study involving patients with glaucoma or suspected of having glaucoma who were followed over time from the Duke Glaucoma Registry. Rates of RNFL loss from spectral-domain optical coherence tomography (SD-OCT) were used to assess disease progression. Generalized estimating equations with robust sandwich variance estimators were used to investigate the effects of the interaction of age at baseline and mean IOP on rates of RNFL loss over time. Models were adjusted for gender, race, diagnosis, central corneal thickness, follow-up time, and baseline disease severity.ResultsThe study included 85,475 IOP measurements and 60,026 SD-OCT tests of 14,739 eyes of 7814 patients. Eyes had a mean follow-up time of 3.5 ± 1.9 years. The average rate of change in RNFL thickness was –0.70 µm/year (95% confidence interval, –0.72 to –0.67). There was a significant interaction between age and mean IOP and the rate of RNFL loss (P = 0.001), with older eyes having significantly faster rates of RNFL loss than younger ones for the same level of IOP. The effect of IOP on rates of change was greater in the inferior and superior regions of the optic disc.ConclusionsAge is a significant modifier of the relationship between IOP and glaucomatous loss in RNFL thickness over time. Older patients may be more susceptible to glaucomatous progression than younger patients at the same level of IOP.

Separation and Thickness Measurements of Superficial and Deep Slabs of the Retinal Nerve Fiber Layer in Healthy and Glaucomatous Eyes

Describe a new method to analyze retinal nerve fiber layer (RNFL) thickness maps. Cross-sectional study. RNFL thickness maps of healthy and glaucomatous eyes. Optical coherence tomography (OCT) RNFL raster scans from 98 healthy and 50 glaucomatous eyes were analyzed. The RNFL thickness maps were separated into superficial (SNFL) and deep (DNFL) slabs through a partial thickness plane set at the modal thickness (mode). Association between mode and OCT signal strength (SS), age, axial length, and visual field mean deviation (VFMD) was tested (Pearson coefficient, r). Thicknesses of inferior and superior SNFL regions (i-,s-SNFL), and inferior, superior, nasal, and temporal DNFL regions (i-,s-,n-,t-DNFL) were calculated. The regions thicknesses were compared between healthy and glaucomatous eyes (t-test) and between glaucomatous eyes with early, moderate, and severe disease (ANOVA and linear regressions of thickness on VFMD). Diagnostic accuracy and correlation with VFMD of RNFL regions thicknesses were calculated as the area under the receiver operating characteristic curve (AUC) and Pearson r, respectively. P<0.05 was considered significant. Thickness of regions in SNFL and DNFL slabs. The mode was not associated with SS, age, axial length, or VFMD, it circumscribed the thicker RNFL around the optic disc of healthy and glaucomatous eyes, and it was used to separate the SNFL and DNFL slabs of RNFL thickness maps. The thickness of the SNFL slab was less in glaucomatous eyes than in healthy eyes (P<0.001). S-SNFL and i-SNFL thicknesses (respectively) were 86.0±8.2μm and 87.3±9.6μm in healthy eyes vs. 66.1±9.1μm and 63.4±8.2μm in glaucomatous eyes (P<0.001 for both). The thickness of the DNFL slab was similar between groups (P=0.19). T-DNFL thickness was 37.0±5.3μm in healthy eyes vs. 33.9±5.0μm in glaucomatous eyes (P<0.001); thicknesses of all other DNFL regions were similar. The SNFL regions only thinned with progressively worse glaucoma severity, had excellent AUCs (AUC≥0.95, P<0.001), and correlated strongly with VFMD (r≥0.60, P<0.001). Glaucomatous RNFL thinning is predominantly detected within a slab with thickness greater than the mode. SNFL thickness has great AUC and correlation with VFMD in glaucomatous eyes. The usefulness for diagnosis and monitoring of glaucoma needs further study.

Comparison of the retinal nerve fiber layer and ganglion cell complex thickness in Korean patients with unilateral exfoliation syndrome and healthy subjects.

PurposeTo compare retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness in patients with unilateral exfoliation syndrome (XFS) and age-matched controls using spectral domain-optical coherence tomography (SD-OCT).Materials and methodsThis prospective case–control study included 54 eyes (the XFS-affected and the fellow eyes) of 27 unilateral XFS patients and 27 eyes of 27 age-matched control subjects. The RNFL and GCC thicknesses were measured using SD-OCT (RT-Vue 100, Optovue, Fremont, CA) after pupillary dilation. RNFL and GCC thicknesses were compared between case and control groups.ResultsThe mean age of XFS patients was 73.3 years and that of age-matched controls was 74.3 years. Both groups demonstrated a male preponderance. Superior RNFL thickness of XFS-affected eyes were significantly thinner than those of the healthy age-matched controls (P = 0.002 by ANOVA). There were no statistically significant differences in the RNFL thickness between both eyes of unilateral XFS patients. Moreover, superior GCC thickness of both eyes in unilateral XFS patients were thinner than those in controls (P = 0.002 by ANOVA).ConclusionsThinner RNFL and GCC thicknesses were observed in unilateral XFS patients without visual field defects. These findings imply that XFS itself might be a risk factor for development of glaucomatous optic disc and RNFL damage.

Screening Glaucoma With Red-free Fundus Photography Using Deep Learning Classifier and Polar Transformation

The main purpose of this study was to develop novel software to determine whether there is a retinal nerve fiber layer (RNFL) defect in a given fundus image using deep learning classifier and, if there is, where it presents. In the deep learning classifier, the bottleneck features were extracted, followed by application of the softmax classifier, which outputted the glaucoma probability. For localization of RNFL defect, an image processing algorithm was implemented as follows: (1) the given image was normalized to enhance the contrast; (2) the region of interest (ROI) was set as the circumferential area surrounding the optic disc (internal diameter: 2 disc diameters, external diameter: 3 disc diameter), and converted to a polar image; (3) blood vessels were removed and the average curvatures were calculated. If the local maximum curvature was greater than the cut-off value, the sector was considered to be an RNFL defect.The images of 100 normal healthy controls and 100 open-angle glaucoma patients were enrolled. Maximum curvatures and area under receiver operating characteristic curve were compared to determine the diagnostic validity. There were no significant differences in age or sex (P=0.275, P=0.479, respectively) between the 2 groups. In the glaucoma group, the mean deviation was -4.9±5.4 dB. There was a significant difference of maximum curvature (14.37±5.13 in control group, 20.67±10.56 in glaucoma group, P<0.001). Area under receiver operating characteristic curve was 0.939 in deep learning classifier and 0.711 in maximum curvature. The proposed software can be an effective tool for automated detection of RNFL defect.

Transverse Separation of the Outer Retinal Layer at the Peripapillary in Glaucomatous Myopes

Glaucoma specialists often overlook the outer retinal changes because the glaucomatous optic neuropathy typically involves retinal nerve fiber layer (RNFL). By detailed inspection of the outer retina in myopic eyes, we observed a separation of the inner nuclear layer (INL) from the outer nuclear layer (ONL) at the peripapillary sclera (pp-sclera). Therefore, we conducted a retrospective observation of 108 eyes of 108 Korean subjects with myopia assessed by swept-source optical coherence tomography (SSOCT) and divided into normal and glaucomatous eyes. Mean subject age, refractive error and axial length difference between 2 groups were insignificant, respectively. To quantify the ONL-INL separation, straight-line distance from ONL endpoint to INL endpoint was measured at the center of the optic disc by SSOCT horizontal scan. The glaucomatous group had significantly large ONL-INL separation than the non-glaucomatous group (p = 0.027) but had no significant difference in INL – Anterior scleral canal opening (ASCO) separation. The width of ONL-INL separation were associated with β-peripapillary atrophy (β-PPA), degree of horizontal tilt of the optic disc and worse glaucomatous RNFL defect by Pearson’s correlation analysis (all p < 0.001, respectively). In conclusion, we demonstrate transverse separation of INL from ONL at the peripapillary region, which was significantly associated with glaucomatous optic nerve damage. These observations may be of interest to elucidate the role of PPA in glaucoma pathogenesis and a clinical index to take notice for myopic subjects.

Spectral-Domain OCT: Helping the Clinician Diagnose Glaucoma: A Report by the American Academy of Ophthalmology

To review the current published literature on the use of spectral domain (SD) OCT to help detect changes associated with the diagnosis of glaucoma. Searches of the peer-reviewed literature were conducted on June 11, 2014, November 7, 2016, August 8, 2017, and April 19, 2018, in the PubMed and Cochrane Library databases and included only articles published since the last glaucoma imaging Ophthalmic Technology Assessment, which included articles up until February 2006. The abstracts of these 708 articles were examined to exclude reviews and non-English articles. After inclusion and exclusion criteria were applied, 74 articles were selected, and the panel methodologist (K.N.-M.) assigned ratings to them according to the level of evidence. Two articles were rated level I, 57 articles were rated level II, and the 15 level III articles were excluded. Spectral-domain OCT is capable of detecting damage to the retinal nerve fiber layer (RNFL), macula, and optic nerve in patients with preperimetric and perimetric glaucoma (level I and II evidence). The most commonly studied single parameter was RNFL thickness. Of note, RNFL thickness measurements are not interchangeable between instruments. Various commercially available SD OCT instruments have similar abilities to distinguish patients with known glaucoma from normal subjects. Despite different software protocols, all SD OCT instruments are able to detect the same typical pattern of glaucomatous RNFL loss that affects primarily the inferior, inferior temporal, superior, and superior temporal regions of the optic nerve (level II evidence). Across many SD OCT instruments, macular imaging also can detect a preferential inferior, inferior temporal, and superior temporal thinning in patients with glaucoma compared with controls. Best disc parameters for detecting glaucomatous nerve damage are global rim area, inferior rim area, and vertical cup-to-disc ratio. Studies suggest that newer reference-plane independent optic nerve parameters may have the same or better detection capability when compared with older reference-plane dependent disc parameters (level II evidence). Structural glaucomatous damage can be detected by SD OCT. Optic nerve, RNFL, and macular parameters can help the clinician distinguish the anatomic changes that are associated with patients with glaucoma when compared with normal subjects.

Location of Disc Hemorrhage and Direction of Progression in Glaucomatous Retinal Nerve Fiber Layer Defects

To investigate the relationship between glaucomatous disc hemorrhage (DH) location with respect to the nasal or temporal margin of the retinal nerve fiber layer defect (RNFLD) and the direction of RNFLD widening. This is a retrospective, cross-sectional study. Patients with any documented episode of glaucomatous DH throughout the follow-up period, and definite RNFLD widening on retinal nerve fiber layer photographs were analyzed. The location of DH was recorded as either nasal or temporal, and the direction of RNFLD widening was investigated. The laterality of DH location on the RNFLD border and the direction of RNFLD widening were correlated with each other. We also compared clinical parameters between eyes with nasal versus temporal margin DHs. We analyzed 123 eyes from 116 patients with definite widening of the RNFLD and glaucomatous DH at the border between the healthy and damaged retinal nerve fiber layer. The most common diagnosis was normal-tension glaucoma (109, 87.9%). The most frequent location of DH was the temporal margin of an inferotemporal RNFLD (75, 61.0%), and the most frequent pattern of change in RNFLD was temporal widening (89, 72.4%). The absolute congruency was 82.9% and the total congruency was 99.2%. No significant differences were identified between eyes with nasal versus temporal margin DHs. The lateral location of DH on the RNFLD border was highly congruent with the direction of RNFLD widening. This correspondence of laterality between DH development and progression of RNFLD may suggest an intimate structural relationship during the pathogenesis of DH, at the enlarging RNFLD border.

Systemic Vascular Risk Factors for Multiple Retinal Nerve Fiber Layer Defects

Multiple retinal nerve fiber layer (RNFL) defects develop uncommonly, even though glaucomatous RNFL loss is typically observed as one RNFL defect in each quadrant. We investigated the risk factors associated with multiple RNFL defects to increase our understanding of the nature and pathogenesis of various RNFL defect patterns. Data from subjects with multiple RNFL defects (28 patients) and glaucoma patients without multiple RNFL defects (194 patients) were analyzed. The term “multiple RNFL defects” refers to three or more isolated defects separated by a comparatively normal area. Patients with multiple RNFL defects showed a higher prevalence of hypertension, end-stage renal disease, and cerebrovascular disease than those without multiple RNFL defects, both before and after propensity score matching for age and mean deviation (all P < 0.05). The number of patients with parafoveal visual field points depressed <5% on pattern deviation plots was higher in subjects with multiple RNFL defects than in those without multiple RNFL defects (P = 0.048). In conclusion, the presence of multiple RNFL defects had clinical relevance for systemic vascular risk factors and a higher risk of parafoveal scotoma. Clinicians should be aware of the possibility of concomitant systemic vascular disease when evaluating patients with multiple RNFL defects.

Association Between Optic Disc Hemorrhage and Renal Function in South Korea.

The purpose of this article is to investigate the relationship between renal function and disc hemorrhage (DH). This retrospective cross-sectional survey was conducted at Kangbuk Samsung Hospital Health Screening Center between August 2012 and July 2013, and a total of 168,044 participants at least 20 years of age who voluntarily visited the health screening center for systemic and ophthalmologic examinations, including fundus photography, were enrolled. All subjects underwent a physical examination and provided samples for laboratory analysis. Digital fundus photographs of both eyes were taken and reviewed. Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine concentration using the Modification of Diet in Renal Disease (MDRD) formula and Cockcroft-Gault (CG) formula. Subjects were stratified by eGFR into quartiles. Among participants, 220 (0.1%) showed DH, and 2376 (1.6%) showed glaucomatous retinal nerve fiber layer defects. The DH group showed higher creatinine and lower eGFR than the non-DH group. A significant trend was observed among higher creatinine, decreased eGFR as obtained by the MDRD and CG formulas, and the prevalence of DH (P for trend ≤0.003, logistic regression analysis). A multiple logistic regression model adjusted for age, sex, hypertension, diabetes, and hyperlipidemia showed that the lowest eGFR quartiles estimated by MDRD and CG were significantly associated with DH compared with the highest eGFR quartile (adjusted odds ratio, 1.96; 95% confidence interval, 1.22-3.14 by CG, 1.86; 95% confidence interval, 1.17-2.96 by MDRD). Renal function impairment was independently associated with a higher prevalence of DH in a South Korean population.

OCT Glaucoma Staging System: a new method for retinal nerve fiber layer damage classification using spectral-domain OCT.

PurposeTo describe a new method, the Optical Coherence Tomography (OCT) Glaucoma Staging System, for classifying retinal nerve fiber layer (RNFL) damage assessed with OCT.Patients and methodsThe OCT Glaucoma Staging System was created based on data obtained from Nidek RS 3000 spectral-domain (sd)-OCT. This system uses the superior and inferior quadrant RNFL thickness values, plotted on an x-y diagram for staging structural damage severity in glaucoma. A non-linear equation and two regression lines describe the boundary lines which separate the different sectors of the diagram. These mathematical formulas have been used to create a software, which provides a quick classification of the RNFL damage. Sensitivity and specificity of the system were assessed in a different cohort including 64 patients with early OAG, and 62 normal subjects.ResultsThree hundred and two OCT tests from 98 healthy controls and 284 patients affected by either ocular hypertension or chronic open-angle glaucoma were considered in order to design the new classification system. The OCT Glaucoma Staging System classifies RNFL defects into 6 stages of increasing severity ranging from borderline to stage 5, and 3 groups according to defect localization (superior, inferior, or diffuse). Sensitivity and specificity in discriminating between healthy and glaucomatous eyes were 95.2 and 91.9%, respectively, considering borderline results as abnormal.ConclusionsThe OCT Glaucoma Staging System appears to provide a standardized and objective classification of glaucomatous RNFL damage. It can be used in day-to-day clinical practice for an easy and fast interpretation of RNFL measurements obtained with OCT.

Parapapillary Deep-Layer Microvasculature Dropout in Glaucoma: Topographic Association With Glaucomatous Damage.

The purpose of this article was to compare the frequencies of the parapapillary deep-layer microvasculature dropout (MvD) detected by optical coherence tomography angiography in eyes with primary open-angle glaucoma (POAG) and healthy eyes and to determine the topographic correlation between the MvD and the glaucomatous retinal nerve fiber layer (RNFL) defect in POAG eyes. Microvasculature in the peripapillary deep-layer was evaluated in 150 POAG patients and 45 healthy controls using swept-source optical coherence tomography angiography to identify an MvD. Frequencies of MvDs were compared between the POAG and control groups. In POAG eyes with MvD, topographic correlation was assessed between the MvD and the RNFL defect defined based on the optical coherence tomography circumpapillary RNFL thickness measurement. MvD was observed as a sectoral filling defect in the parapapillary deep-layer in 53.9% (n = 62) of the POAG eyes, whereas none of the control eyes exhibited an MvD. POAG eyes with MvD had a thinner global RNFL (P < 0.001) and worse visual field mean deviation (P = 0.042) and were more myopic (P = 0.029), with axial length being longer (P = 0.046) than those without MvD. There was a good agreement between the circumferential extent and location of MvD and those of RNFL defect (95% limits of agreement of the difference ranged from -23.4 to 21.9° and -16.2 to 17.0°, respectively). MvD was identified in the parapapillary deep layer exclusively in POAG eyes at the location of glaucomatous damage using optical coherence tomography angiography. The finding suggests that peripapillary deep-layer circulation is directly related to the glaucomatous optic neuropathy.

Reflectance Spectrum and Birefringence of the Retinal Nerve Fiber Layer With Hypertensive Damage of Axonal Cytoskeleton.

PurposeGlaucoma damages the retinal nerve fiber layer (RNFL). This study used precise multimodal image registration to investigate the changes of the RNFL reflectance spectrum and birefringence in nerve fiber bundles with different degrees of axonal damage.MethodsThe reflectance spectrum of individual nerve fiber bundles in normal rats and rats with experimental glaucoma was measured from 400 to 830 nm and their birefringence was measured at 500 nm. Optical measurements of the same bundles were made at different distances from the optic nerve head (ONH). After the optical measurements, the axonal cytoskeleton of the RNFL was evaluated by confocal microscopy to assess the severity of cytoskeletal change.ResultsFor normal bundles, the shape of the RNFL reflectance spectrum and the value of RNFL birefringence did not change along bundles. In treated retinas, damage to the cytoskeleton varied within and across retinas. The damage in retinal sectors was subjectively graded from normal-looking to severe. Change of spectral shape occurred near the ONH in all sectors studied. This change became more prominent and occurred farther from the ONH with increased damage severity. In contrast, RNFL birefringence did not show change in normal-looking sectors, but decreased in sectors with mild and moderate damage. The birefringence of severely damaged sectors was either within or below the normal range.ConclusionsVarying degrees of cytoskeletal damage affect the RNFL reflectance spectrum and birefringence differently, supporting differences in the ultrastructural basis for the two optical properties. Both properties, however, may provide a means to detect disease and to estimate ultrastructural damage of the RNFL in glaucoma.

Relationship between Plasma Homocysteine Level and Glaucomatous Retinal Nerve Fiber Layer Defect

ABSTRACTAims: To investigate the association between plasma homocysteine levels and glaucomatous retinal nerve fiber layer (RNFL) defect in South Korean population.Materials and methods: This retrospective cross-sectional study included subjects who underwent screening at Kangbuk Samsung Hospital Health Screening Center between August 2012 and July 2013. Subjects underwent physical examination and provided samples for laboratory analysis of homocysteine. Subjects were divided equally into four quartiles (Qs) based on plasma homocysteine level. Digital fundus photographs of both eyes were obtained. Determination of glaucomatous disc appearance was based on criteria set forth by the International Society of Geographical and Epidemiological Ophthalmology and based on the appearance of the RNFL and optic disc. Multivariate logistic regression models were used to define elevated glaucoma risk with P < 0.2 on univariate analysis.Results: A total of 78,049 subjects were included; 76,093 subjects were male, and 1956 subjects were female. When analyzed by gender, the mean homocysteine level in the male group with glaucomatous RNFL defects (11.05 ± 3.80 µmol/L) was higher than those without RNFL defects (10.81 ± 4.12 µmol/L (P = 0.000, χ2 test). Upon multifactorial logistic regression analysis adjusted for age, gender, creatinine, diabetes mellitus, hypertension, and hyperlipidemia, glaucomatous RNFL defects had a significant correlation with plasma homocysteine level. Based on the Q2 level, the odds ratio (OR) of Q3 was 1.267, while the OR of Q4 was 1.285 (95% CI = 1.067−1.505, 1.081−1.529, respectively, P for trend = 0.001).Conclusion: Our results suggest that homocysteine level is associated with the presence of glaucomatous RNFL defects.