cpRNFL Thickness Research Articles

Characteristics of a Large Database of Healthy Eyes From Optometry Practices: Implications for a Real-World Reference Database.

To compare an optical coherence tomography (OCT) real-world reference database (RW-RDB) of "healthy" eyes obtained from optometry practices to a commercial reference database (RDB). OCT scans from 6804 individuals 18years and older were sampled from a larger database tested at 10 optometry practices involved in refractive and screening services. Employing a reading center method, OCT scans from both eyes of 4932 (4.9K) individuals were judged to be of acceptable quality with an absence of pathology. The 4.9K RW-RDB was compared to a commercial RDB with 398 eyes (398 RDB). The means and distributions of global circumpapillary retinal nerve fiber layer (G-cpRNFL) and global ganglion cell layer (G-GCL) thickness, as well as five key anatomical parameters affecting cpRNFL thickness, were not significantly different for all but one parameter (fovea-to-disc distance) and one thickness metric (G-cpRNFL). In both cases, the difference amounted to less than 1.5%. By design, the number of 4.9K RW-RDB eyes 70years and older (724, 14.7%) was greater than for the 398 RDB (40, 10.1%). The error bands on the 5% and 1% quantile regression lines (QRLs) were substantially narrower for the 4.9K RW-RDB. The 398 RDB and 4.9K RW-RDB have similar characteristics and appear to come from a similar population. However, the large size of the 4.9K RW-RDB leads to narrower error bands of the QRLs, which has the potential to increase accuracy. The larger RW-RDB offers the opportunity to better characterize healthy eyes for clinical diagnosis and clinical trials by furthering our understanding of the patterns of artifacts, exploring covariates, developing separate RW-RDBs, and/or improving AI models.

Longitudinal evaluation of circumpapillary structure-function and vasculature-function relationships in acute and sub-acute nonarteritic anterior ischemic optic neuropathy

PurposeTo investigate the global and regional correlations between longitudinal structure-function (S-F) and vasculature-function (V-F) using circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements, circumpapillary vessel density (cpVD) and the corresponding/final visual outcomes at different stages of nonarteritic anterior ischemic optic neuropathy (NAION). MethodsThirty eyes of 30 patients with acute NAION were included. LogMAR best-corrected visual acuity(BCVA), mean deviation (MD) and visual field index (VFI), cpRNFL thickness and cpVD across different retinal layers were examined at baseline, 2 weeks and 1 month after diagnosis. Potential correlations between the Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) parameters and visual outcomes were investigated in both acute and sub-acute NAION. ResultsSignificant global and regional correlations in S-F relationship were identified exclusively in sub-acute stage (p < 0.05). However, among the OCTA parameters for the acute NAION, the temporal cpVD in superficial vessel complex (SVC) and inner retinal layer (IRL) exhibited positive correlations with corresponding and final visual acuity and visual field outcomes. In the sub-acute stage of NAION, the cpVD of global or temporal section in radial peripapillary capillary (RPC), SVC and IRL were positively correlated with visual outcomes. ConclusionSignificant longitudinal V-F relationships exist both globally and regionally, in acute and sub-acute NAION. The cpVD parameters of the SVC and IRL are potentially valuable for evaluating corresponding and final visual outcomes and highlights the importance of monitoring cpVD over cpRNFL thickness in acute NAION.

Measurement of the Tilt Angle of the Optic Disc Using Spectral-Domain Optical Coherence Tomography and Related Factors in Myopia.

This study presents a novel, three-dimensional method for measuring the tilt angle of the tilted optic disc (TOD) using spectral-domain optical coherence tomography (SD-OCT) and investigates the correlation between ocular-related parameters and TOD. We included the right eyes of 243 healthy young individuals, categorized by axial length. We measured the ovality index (OI) and dihedral angle (DA) using SD-OCT infrared ray fundus photographs and high-resolution cross-sectional images of the optic disc, respectively. The relationships between OI, DA, and ocular-related parameters were analyzed. Eyes in the longer axial length group exhibited a lower OI and a higher DA, along with thinner nasal and inferonasal circumpapillary retinal nerve fiber layer (cpRNFL) and thicker temporal and superotemporal cpRNFL. There was a significant relationship between DA and cpRNFL thickness. The new method utilizing DA to measure the tilt angle of TOD demonstrated high repeatability. We propose a novel, three-dimensional, and quantitative method for evaluating the tilt degree of TOD. A higher degree of myopia indicated a greater tilt angle of the TOD, and a greater TOD suggested additional changes in cpRNFL thickness. These findings should be considered when interpreting increased susceptibility and early assessment of glaucoma in myopia. DA could serve as a superior indicator for describing TOD morphology during eyeball elongation and evaluating its impact on related parameters of the optic disc and peripapillary structures in the myopic population.

Evaluation of the Inner Macula Layers, Circumpapillary Retinal Nerve Fiber Layer, and Minimum Rim Width Thickness in Patients With Pseudoexfoliation Syndrome Without Glaucoma Compared With Controls.

Minimum rim width (MRW) is thinner in patients with non-glaucomatous pseudoexfoliation syndrome (XFS) and may be the first parameter affected in these patients due to the vascular nature of this disease. To evaluate the macular inner layers, circumpapillary retinal nerve fiber layer (cp-RNFL), and MRW in non-glaucomatous XFS compared with healthy patients. In this prospective study, using Heidelberg Spectralis optical coherence tomography with Glaucoma Module Premium Edition, 8×8 grids of macular inner layers were exported, and the global, superior, and inferior thicknesses were used. Also, on the deviation map, the elliptical annulus around the fovea, which was 4.8×4mm in size, was analyzed. Moreover, both groups calculated cp-RNFL and MRW values in 3 superior and 3 inferior sectors. Thirty-two eyes of 32 patients with clinically detected non-glaucomatous XFS and 30 right eyes of age-sex-matched healthy controls were included. No significant difference was found between the case and control groups concerning the intraocular pressure (14.94 ± 2.09 vs 15.27 ± 2.27 mm Hg, respectively, P = 0.556). The MRW of the superotemporal segment (MRW-temporal superior) was significantly thinner in the XFS group compared with the control ones (303.69 ± 60.49 vs 341.43 ± 56.19µm, P = 0.014). No significant differences were found in the other sectors of MRW, macular inner layers, and cp-RNFL thickness between the groups. These findings indicate that the MRW, especially in the superotemporal sector, may show early eye damage in patients with non-glaucomatous XFS, and it may be used to detect the early stage of glaucoma in XFS.

Association between metformin use with circumpapillary retinal nerve fibre layer thickness and capillary vessel density in glaucoma

Background/aimsTo investigate the association between use of metformin and circumpapillary retinal nerve fibre layer (cpRNFL) thickness, as well as whole image capillary density (wiCD), in patients with glaucoma.MethodsThis cross-sectional study...

Diagnostic ability of macular nerve fiber layer thickness measured by swept-source optical coherence tomography in preperimetric glaucoma.

We evaluated the diagnostic ability of macula retinal nerve fiber layer (mRNFL) thickness in preperimetric glaucoma (PPG) patients. This prospective study included 83 patients with PPG and 83 age- and refractive error-matched normal control subjects. PPG was defined as a localized RNFL defect corresponding to glaucomatous optic disc changes with a normal visual field test. We used spectral-domain (SD) optical coherence tomography (OCT) to measure the circumpapillary RNFL (cpRNFL) thickness and macular ganglion cell-inner plexiform layer (GCIPL) thickness. Swept-source (SS) OCT was used to measure cpRNFL thickness, macular ganglion cell layer + inner plexiform layer (IPL) thickness (GCL+), and macular ganglion cell layer + IPL+ mRNFL thickness (GCL++). The mRNFL thickness was defined as GCL++ minus GCL+. To evaluate the diagnostic power of each parameter, the area under the receiver operating characteristics curve (AUROC) was analyzed to differentiate PPG from the normal groups. Using SD-OCT, all GCIPL parameters and most cpRNFL parameters, except at the nasal and temporal quadrant, were significantly lower in PPG versus normal controls. PPG eyes had significantly smaller values than normal controls for all cpRNFL and GCL parameters measured by SS-OCT, except mRNFL at the superonasal area. The inferotemporal GCL++ had the largest AUROC value (0.904), followed by inferotemporal GCL+ (0.882), inferotemporal GCIPL thickness (0.871), inferior GCL++ (0.866), inferior cpRNFL thickness by SS-OCT (0.846), inferior cpRNFL thickness by SD-OCT (0.841), and inferotemporal mRNFL thickness (0.840). The diagnostic performance was comparable between inferotemporal mRNFL thickness and the best measures of GCL (inferotemporal GCL++, p = 0.098) and cpRNFL (inferior cpRNFL thickness by SS-OCT, p = 0.546). The diagnostic ability of mRNFL thickness was comparable to that of the best measures of cpRNFL and GCL analysis for eyes with PPG. Therefore, mRNFL thickness could be a new parameter to detect early structural changes in PPG.

Anatomical Features can Affect OCT Measures Used for Clinical Decisions and Clinical Trial Endpoints.

To understand the association between anatomical parameters of healthy eyes and optical coherence tomography (OCT) circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements. OCT cpRNFL thickness was obtained from 396 healthy eyes in a commercial reference database (RDB). The temporal quadrant (TQ), superior quadrant (SQ), inferior quadrant (IQ), and global (G) cpRNFL thicknesses were analyzed. The commercial OCT devices code these values based on percentiles (red, <1%; yellow, ≥1% and <5%), after taking age and disc area into consideration. Four anatomical parameters were assessed: fovea-to-disc distance, an estimate of axial length, and the locations of the superior and the inferior peaks of the cpRNFL thickness curve. Pearson correlation values were obtained for the parameters and the thickness measures of each of the four cpRNFL regions, and t-tests were performed between the cpRNFL thicknesses coded as abnormal (red or yellow, <5%) versus normal (≥5%). For each of the four anatomical parameters, the correlation with the thickness of one or more of the TQ, SQ, IQ, and G regions exceeded the correlation with age or disc area. All four parameters were significantly (P < 0.001) associated with the abnormal cpRNFL values. The significant parameters were not the same for the different regions; for example, a parameter could be negatively correlated for the TQ but positively correlated with the SQ or IQ. In addition to age and disc area, which are used for inferences in normative databases, four anatomical parameters are associated with cpRNFL thickness. Taking these additional anatomical parameters into consideration should aid diagnostic accuracy.

Evaluation of Optic Nerve Head Microcirculation in Open-Angle Glaucoma Patients with Unilateral Visual Field Defect

Introduction: Microcirculation of optic nerve head (ONH) in open-angle glaucoma (OAG) patients with unilateral visual field (VF) loss has yet to be fully investigated, especially the perimetrically unaffected fellow eyes. Methods: Thirty-eight OAG patients with VF defect in one eye and normal VF in the other eye, and thirty-one healthy participants were analyzed. All participants underwent laser speckle flowgraphy (LSFG), spectral-domain optical coherence tomography (SD-OCT) imaging, and VF test for further analyses. LSFG measurements included mean blur rate in all area of ONH (MA), big vessel area of ONH (MV), and tissue area of ONH (MT). SD-OCT parameters included circumpapillary retinal nerve fiber layer (cpRNFL) thickness and macula thicknesses. The difference of LSFG and SD-OCT indices between glaucoma patients and healthy controls were compared. The diagnostic accuracy was analyzed with the areas under the receiver operating characteristic curves (AROCs). Results: Global cpRNFL thickness and macular thickness in unaffected eyes of OAG patients were higher than their fellow eyes and lower than healthy eyes. MA and MV in healthy eyes and unaffected eyes were significantly higher than in affected eyes. MT in unaffected eyes of OAG patients was higher than in their fellow affected eyes but lower than in healthy eyes. The AROCs were highest for cpRNFL (0.925), followed by macular thickness (0.838), and MT (0.834). Conclusions: ONH microcirculation in perimetrically unaffected fellow eyes was decreased in OAG patients with unilateral VF loss. LSFG can detect changes of ONH in high-risk eyes before detectable VF damage, which may reflect the vascular pathophysiology for glaucoma.

Parapapillary choroidal microvasculature dropout in eyes with primary open-angle glaucoma

The purpose of this study was to evaluate how various parameters are related to microvasculature dropout (MvD) area measured using optical coherence tomography angiography (OCTA). We measured the area of MvD in 55 patients with primary open-angle glaucoma (POAG). Using OCTA, MvD area and peripapillary choroidal atrophy (PPA) area were assessed in a 4.5 mm × 4.5 mm region. The following were examined: circumpapillary nerve fiber layer (cpRNFL) thickness, optic disc area, optic disc cupping area, optic disc rim area, Humphrey Field Analyzer (HFA) 24/10–2 mean deviation (MD), and pattern standard deviation (PSD). The relationship between MvD area and each parameter was evaluated using Spearman’s rank correlation coefficient analysis. Mean MvD area and PPA area were 0.18 ± 0.17 mm2 and 1.13 ± 0.72 mm2, respectively. MvD area was significantly correlated with optic disc rim area (p = 0.0017), cpRNFL (p = 0.0027), HFA 24/10–2 MD, and PSD (p < 0.001). In eyes with POAG, MvD area indicates the severity of glaucoma, which might be associated with structural changes in the peripapillary vasculature around the optic disc.

Larger Tumor Volume is Associated with Visual Acuity Loss and Axonal Degeneration in Children with Optic Pathway Gliomas Secondary to Neurofibromatosis Type 1

Abstract BACKGROUND We investigated whether volumetric magnetic resonance imaging (MRI) measures of the anterior visual pathway (AVP) in optic pathway gliomas secondary to Neurofibromatosis type 1 (NF1-OPG) are associated with visual acuity (VA) loss and axonal loss, as measured using optical coherence tomography (OCT). METHODS Children with NF1-OPGs enrolled in a prospective study of VA and OCT measures of the circumpapillary retinal nerve fiber layer (cpRNFL) thickness were eligible if they had undergone 3-Tesla MRI that included a T1-weighted volumetric sequence. The linear dimension and volume of the optic nerves, chiasm and optic tracts were measured using our semi-automated algorithm. The combined volume of these components comprising the proximal AVP was used as a surrogate of total tumor burden. Regression models for VA and cpRNFL thickness were reported on a per-eye basis. RESULTS Fifty-two study eyes (26 children, mean 7.1 years) met inclusion criteria, of which 40% (N=21 eyes) had abnormal VA. In regression analysis, only total AVP volume demonstrated a significant relationship to axonal loss, such that for every 1 ml increase in AVP volume, cpRNFL declined by 5.4 microns (p = 0.01). Total AVP volume &amp;gt; 1.75 ml predicted both axonal loss and abnormal VA (positive predictive value of 83.3% and 70.8%, respectively; negative predictive value of 80.0% and 88.0%, respectively). CONCLUSIONS Volumetric measures of NF1-OPGs identified children with VA loss and axonal degeneration. Total tumor burden, as measured by AVP volume, had the strongest relationship with axonal injury. NF1-OPG volumetric measures may be helpful in making treatment decisions.

Evaluation of inner retinal function at different stages of primary open angle glaucoma using the photopic negative response (PhNR) measured by RETeval electroretinography.

To investigate the objective function of the inner retinal layer in each stage of primary open angle glaucoma (POAG) using the photopic negative response (PhNR) measured by RETeval full-field electroretinography (ERG), and to identify which PhNR parameter is the most useful. Ninety eyes of 90 patients with POAG (30 with mild POAG (mean deviation (MD) ≥ -6dB) and 60 with moderate-to-advanced POAG (MD < -6dB)) and 76 eyes of 76 control cases were examined. We investigated six PhNR parameters and their relationships with the results of the Humphrey 30-2 visual field test and the thickness of the circumpapillary retinal nerve fiber layer (cpRNFL) obtained from optical coherence tomography. The following PhNR parameters were assessed: base-to-trough (BT), peak-to-trough (PT), 72msPhNR, the W-ratio, P-ratio, implicit time (IT), and a-wave and b-wave amplitudes on ERG. All PhNR parameters other than IT significantly differed between the all POAG (all stages) and control groups and between the moderate-to-advanced POAG and control groups. BT and 72msPhNR in the mild POAG group, significantly differed from those in the control group. Regarding the relationships between PhNR parameters and the visual field and between these parameters and cpRNFL thickness, correlations were observed between all PhNR parameters, except PT and IT, and both the visual field and cpRNFL thickness in the all and moderate-to-advanced POAG groups. 72msPhNR correlated with cpRNFL thickness in the mild POAG group. The area under the receiver operating characteristic curve was greater for BT than for the other PhNR parameters in both the mild and moderate-to-advanced POAG groups. The discriminant linear function for examining the presence or absence of POAG and the threshold for diagnosis were quantitatively obtained as follows. Regarding BT: discriminant = 0.505 × BT + 2.017; threshold = positive for POAG, negative for no POAG; correct answer rate = 80.7%. Concerning 72msPhNR: discriminant = 0.533 × 72msPhNR + 1.553; threshold = positive for POAG and negative for no POAG; correct answer rate = 77.1%. RETeval-measured PhNR parameters were useful for an objective evaluation of visual function in moderate-to-advanced POAG. BT appeared to be the most diagnostically useful parameter.

Longitudinal Assessment of Retinal Nerve Fiber Layer and Ganglion Cell Complex Thicknesses in Patients With Large Optic Disc Cups and Normal Intraocular Pressure and Visual Fields.

The thicknesses of the circumpapillary retinal nerve fiber layer (cpRNFL) and ganglion cell complex (GCC) did not change during 5 years in physiological large disc cupping. We evaluated longitudinal changes in the thicknesses of the cpRNFL and GCC in large disc cupping with a normal intraocular pressure (IOP) (<21mmHg) and visual field. This retrospective, consecutive case series study included 269 eyes of 269 patients with large disc cupping and normal IOP. We analyzed patient demographics, IOP, central corneal thickness, vertical cup-to-disc ratios using color fundus photography, the thicknesses of the cpRNFL and GCC using RTVue-100, and mean deviation using visual field examinations. The differences in IOP, vertical cup-to-disc ratios, and mean deviation between the baseline and each follow-up visit were not statistically significant. The baseline average and mean average at 60 months follow-up of the cpRNFL thickness were 106.5±8.5 and 105.1±9.3μm, respectively; differences between the baseline and each follow-up visit were not statistically significant. The baseline average and mean average at 60 months follow-up of the GCC thickness were 82.8±9. and 81.5±9.2μm, respectively; differences between baseline and each follow-up visit were not statistically significant. The thicknesses of the cpRNFL and GCC did not change in well-maintained optic nerve head findings with normal IOP and visual field during a 5-year follow-up period. Optical coherence tomography evaluations of the thicknesses of the cpRNFL and GCC help accurately diagnose physiological optic disc cupping.

Evaluation of optic nerve head and retinal layers in affected and fellow eyes of pediatric glaucoma

ObjectivePediatric glaucoma is a rare disease that is potentially more severe than adult glaucoma because it is more challenging to diagnose and more difficult to treat. The segmented retinal layer has been shown to have excellent capability in assessing adult glaucoma. However, there is limited information regarding the benefits of spectral domain-optical coherence tomography (SD-OCT) in children. Thus, our study aims to investigate the role of circumpapillary (cp) OCT analysis in examining pediatric glaucoma and characterizing the changes in the fellow eyes of glaucomatous children. MethodsSD-OCT was used to investigate the optic nerve head (ONH) and retinal morphology of 18 patients with pediatric glaucoma and 14 matched healthy controls. ResultsAs predicted, pediatric patients with glaucoma had a wider disk diameter, cup diameter, and cup-to-disk ratio (CDR). Pediatric glaucoma also resulted in a thinner retinal nerve fiber layer (RNFL), ganglion cell layer – inner plexiform layer (GCL-IPL), photoreceptor layer – retinal pigment epithelium (PRL-RPE), and total retinal layer (TRL). Similarly, these observations were found in the fellow eyes of glaucomatous children. Our finding also indicated that cpRNFL, GC-IPL, and PRL-RPE thickness were useful for the early identification of pediatric glaucoma. ConclusionIn conclusion, SD-OCT could be implemented in managing glaucoma in young children. Moreover, retinal layer damage at the corresponding locations of the fellow eye is similarly detected in the glaucomatous eye.

Changes of Optic Disc and Macular Vessel Perfusion Density in Primary Angle Closure Glaucoma: A Quantitative Study Using Optical Coherence Tomography Angiograph

Introduction: This study aims to investigate the changes of retinal vascular system in primary angle closure glaucoma (PACG) and acute primary angle closure (APAC) by optical coherence tomography (OCT) angiograph (OCTA) and to evaluate the diagnostic ability of changes of vessel density (VD) in different sectors and layers of optic disc and macular area in APAC and PACG. Methods: In this cross-sectional, observational study, 21 APAC patients (22 eyes) and 21 PACG patients (27 eyes) along with 17 healthy people were enrolled from August 2018 to March 2019. Optic disc region and macular region were imaged using swept-source OCTA system. VD of the macular region was quantified by Image J (1.52a, USA) and Matlab 2018a. The circumpapillary retinal nerve fiber layer (cpRNFL) thickness and ganglion cell complex thickness were obtained by spectral-domain OCT. Results: Compared with the healthy group, the cpRNFL thickness in superior sector was thicker in the APAC group, and this area had the most diffuse microvascular dropout as well. The difference in the macular superficial capillary plexus (SCP) VD between APAC and the control group was not statistically significant. The area under the ROC curves (AUC) of the total optic disc VD in the radial peripapillary capillary (RPC) layer was higher than the AUC of the papillary VD in the optic nerve head (ONH) layer. Compared to the control group, the total optic disc VD, peripapillary VD, and each quadrant of peripapillary VD were decreased in PACG (p < 0.01). In PACG macular region, SCP VD, and deep capillary plexus (DCP) VD, parafovea VD (except temporal sectors) decreased (p < 0.01). The PACG eyes had a greater decrease percentage of VD in total ONH than total macula. The diagnostic value of the VD in the ONH layer and the RPC layer was similar. The diagnostic value of the SCP VD in the macula was greater than the DCP VD in the macula. The AUC was no significant difference between cpRNFL thickness and the total optic disc VD AUC. Conclusion: Elevated intraocular pressure preferentially affects vascular perfusion in the optic disc region more than the macular region in APAC and PACG. In the APAC eyes, there was a perfusion defect in the optic disc region and an increase in RNFL thickness. In this study, the OCTA vascular parameters have similar performance to the OCT structural parameters for glaucoma diagnosis in PACG.

Early Detection of Primary Open Angle, Angle Closure, and Normal Tension Glaucoma in an Asian Population Using Optical Coherence Tomography.

Spectral-domain optical coherence tomography (SD-OCT) facilitates early glaucoma detection in the Chinese population in Taiwan. The best parameters for primary open angle glaucoma (POAG), primary angle closure glaucoma (PACG), normal tension glaucoma (NTG), and suspected glaucoma (GS) detection are temporal inferior Bruch's membrane opening-minimum rim width (BMO-MRW), inner temporal macular ganglion cell layer (mGCL), temporal superior Circumpapillary retinal nerve fiber layer (cpRNFL), and mean global BMO-MRW, respectively. We investigated the diagnostic capability of SD-OCT for different types of early glaucoma among the Chinese population in Taiwan. One eye each was assessed from 113 individuals with healthy eyes, 125 individuals with suspected glaucoma (GS), and 156 patients with early glaucoma (POAG, 87; PACG, 50; and NTG, 19). Circumpapillary (cp) RNFL thickness (global and sectoral), BMO-MRW, and macular parameters, including the macular RNFL (mRNFL), mGCL, and macular inner plexiform layer (mIPL), were assessed using SD-OCT. The areas under receiver operator characteristic curves (AUCs) were calculated to evaluate the diagnostic capacity of the parameters to differentiate between healthy and early glaucomatous eyes. The parameters most suitable for detecting early POAG, PACG, NTG, and GS were temporal inferior BMO-MRW (AUC, 0.847), inner temporal mGCL (AUC, 0.770), temporal superior cpRNFL (AUC, 0.861), and mean global BMO-MRW (AUC, 0.768), respectively. Among the macular parameters, the mGCL exhibited the highest diagnostic capacity. The diagnostic capacity of the mGCL was lower than that of cpRNFL and BMO-MRW for POAG and NTG but not PACG. After adjusting for confounding variables in multivariable analysis, the AUC was determined to be 0.935 for POAG and 0.787 for GS. SD-OCT facilitates the detection of early POAG, PACG, and NTG. Using a combination of cpRNFL, BMO-MRW, and macular parameters may enhance their diagnostic capacities. Further studies are necessary to validate these findings.

Effect of Testing Frequency on the Time to Detect Glaucoma Progression With Optical Coherence Tomography (OCT) and OCT Angiography

To determine how the frequency of testing affects the time required to detect statistically significant glaucoma progression for circumpapillary retinal nerve fiber layer (cpRNFL) with optical coherence tomography (OCT) and circumpapillary capillary density (cpCD) with OCT angiography (OCTA). Retrospective, observational cohort study. In this longitudinal study,156 eyes of 98 patients with glaucoma followed up over an average of 3.5 years were enrolled. Participants with 4 or more OCT and OCTA tests were included to measure the longitudinal rates of cpRNFL thickness and cpCD change over time using linear regression. Estimates of variability were then used to re-create real-world cpRNFL and cpCD data by computer simulation to evaluate the time required to detect progression for various loss rates and different testing frequencies. The time required to detect a statistically significant negative cpRNFL and cpCD slope decreased as the testing frequency increased, albeit not proportionally. cpCD detected progression slightly earlier than cpRNFL. Eighty percent of eyes with a cpCD loss of -1%/y were detected after 6.0, 4.2, and 4 years when testing was performed 1, 2, and 3 times per year, respectively. Progression in 80% of eyes with a cpRNFL loss of -1 µm/y was detected after 6.3, 5.0, and 4.2 years, respectively. cpRNFL and cpCD are comparable in detecting progression. As there were only small changes in the time to detect progression when testing increased from 2 to 3 times per year, testing twice per year may provide sufficient information for detecting progression with either OCT or OCTA in clinical settings.

Comparison of Diagnostic Ability Between Wide-Field Swept-Source Optical Coherence Tomography Imaging Maps and Heidelberg Retina Tomograph 3 Optic Nerve Head Assessment to Discriminate Glaucomatous and Non-glaucomatous Eyes.

BackgroundIn this study, we aimed to determine the diagnostic performance of optic nerve head (ONH), macular, and circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements of wide-field maps (12 × 9 mm) using swept-source optical coherence tomography (SS-OCT) compared to measurements of the ONH and RNFL parameters measured by Heidelberg Retina Tomograph (HRT3).MethodologyThis case-control study included 39 eyes of 39 glaucoma patients and 36 eyes of 36 normal subjects (control group). All participants underwent standard automated perimetry (SAP) as well as structural measurements by SS-OCT (DRI-OCT, Triton; Topcon Inc., Tokyo, Japan) and HRT3 (Heidelberg Engineering, Heidelberg, Germany). The abilities of the continuous parameters to discriminate between glaucoma and control groups were assessed using areas under the receiver operating characteristic curves (AUCs). To assess the glaucoma diagnostic abilities of each of the categorical variables, sensitivity, specificity, positive predictive value, and negative predictive value were tested.ResultsThe highest sensitivities were achieved by the DRI-OCT categorical parameters of Superpixel-200 map and cpRNFL (12 sectors) thickness analysis. The best performing HRT3 continuous parameter was rim volume (AUC = 0.829, 95% confidence interval (CI) = 0.735-0.922), and the best continuous parameter for DRI-OCT wide-field was vertical cdr (AUC = 0.883, 95% CI = 0.805-0.951), followed by total cpRNFL thickness (AUC = 0.862, 95% CI = 0.774-0.951). AUCs for disc area, rim area, linear cdr, and RNFL thickness were not significantly different between the two technologies. Using either the most or the least specific criteria, SuperPixel-200 map always showed the highest sensitivity among the categorical parameters of both technologies (82.1% and 89.7%, respectively). The highest sensitivity among HRT3 classification parameters was shown by MRA and GPS classification algorithms.ConclusionsBoth wide-field DRI-OCT maps and HRT3 showed good diagnostic performance in discriminating glaucoma. Although DRI-OCT thickness values and normative diagnostic classification showed the best performance, more studies are required to determine the clinical role of wide-field DRI-OCT scan in glaucoma diagnosis.

Distinguishing Healthy From Glaucomatous Eyes With Optical Coherence Tomography Global Circumpapillary Retinal Nerve Fiber Thickness in the Bottom 5th Percentile.

Two novel, quantitative metrics, and 1 traditional metric were able to distinguish between many, but not all healthy and glaucomatous eyes in the bottom 5th percentile of global circumpapillary retinal nerve fiber layer (cpRNFL) thickness. To test the hypothesis that objective optical coherence tomography measures can distinguish between a healthy control with global cpRNFL thickness within the lower 5% of normal and a glaucoma patient with an equivalent cpRNFL thickness. A total of 37 healthy eyes from over 700 normative eyes fell within the bottom 5th percentile in global cpRNFL thickness. The global cpRNFL thickness of 35 glaucomatous eyes from 188 patients fell within the same range. For the traditional methods, the global cpRNFL thickness percentile and the global ganglion cell layer (GCL) thickness percentile for the central ±8 degrees, were calculated for all 72 eyes. For the novel cpRNFL method, the normalized root mean square (RMS) difference between the cpRNFL thickness profile and the global thickness-matched normative thickness profile was calculated. For the superior-inferior (SI) GCL method, the normalized mean difference in superior and inferior GCL thickness was calculated for the central ±8 degrees. The best quantitative metric, the RMS cpRNFL method, had an accuracy of 90% compared with 81% for the SI GCL and 81% for the global GCL methods. As expected, the global cpRNFL had the worst accuracy, 72%. Similarly, the RMS cpRNFL method had an area under the curve of 0.93 compared with 0.83 and 0.84 for the SI GCL and global GCL methods, respectively. The global cpRNFL method had the worst area under the curve, 0.75. Quantitative metrics can distinguish between most of the healthy and glaucomatous eyes with low global cpRNFL thickness. However, even the most successful metric, RMS cpRNFL, missed some glaucomatous eyes.

A multi-regression framework to improve diagnostic ability of optical coherence tomography retinal biomarkers to discriminate mild cognitive impairment and Alzheimer\u2019s disease

BackgroundDiagnostic performance of optical coherence tomography (OCT) to detect Alzheimer’s disease (AD) and mild cognitive impairment (MCI) remains limited. We assessed whether compensating the circumpapillary retinal nerve fiber layer (cpRNFL) thickness for multiple demographic and anatomical factors as well as the combination of macular layers improves the detection of MCI and AD.MethodsThis cross-sectional study of 62 AD (n = 92 eyes), 108 MCI (n = 158 eyes), and 55 cognitively normal control (n = 86 eyes) participants. Macular ganglion cell complex (mGCC) thickness was extracted. Circumpapillary retinal nerve fiber layer (cpRNFL) measurement was compensated for several ocular factors. Thickness measurements and their corresponding areas under the receiver operating characteristic curves (AUCs) were compared between the groups. The main outcome measure was OCT thickness measurements.ResultsParticipants with MCI/AD showed significantly thinner measured and compensated cpRNFL, mGCC, and altered retinal vessel density (p < 0.05). Compensated RNFL outperformed measured RNFL for discrimination of MCI/AD (AUC = 0.74 vs 0.69; p = 0.026). Combining macular and compensated cpRNFL parameters provided the best detection of MCI/AD (AUC = 0.80 vs 0.69; p < 0.001).Conclusions and relevanceAccounting for interindividual variations of ocular anatomical features in cpRNFL measurements and incorporating macular information may improve the identification of high-risk individuals with early cognitive impairment.

Morphological and vascular characteristics of the optic nerve head of normal guinea pigs

The morphological and vascular characteristics of the optic nerve head (ONH) of normal guinea pigs have not been fully recognized. Therefore, we aimed to investigate them using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). We measured the refractive error, axial length, and intraocular pressure (IOP) and performed OCT and OCTA of the ONH of 3- and 4-week-old tricolour guinea pigs. A total of 208 right eyes from 208 normal guinea pigs were examined. The refractive error (both myopic and hyperopic) of the 3-week group was significantly higher than that of the 4-week group (p < 0.001), the IOP of the 3-week group was significantly lower than that of the 4-week group (p = 0.014), and the circumpapillary retinal nerve fibre layer (cpRNFL) of the 3-week group was significantly thicker than that of the 4-week group (p = 0.048). There were no significant differences in the average vessel area, vascular density, total number of junctions, total vessel length, total number of endpoints, and vascular diameter between the two groups. However, an age-adjusted linear regression analysis revealed that the total vessel length was positively associated with the cpRNFL thickness (p = 0.024) and negatively associated with IOP (p = 0.016). This is the first report on morphological and vascular characteristics of the ONH in normal guinea pigs based on in vivo OCT and OCTA imaging and quantification of ONH parameters. These results may contribute to further research on myopia using guinea pig models.