Cirrus Optical Coherence Tomography Research Articles

Deep learning-based image quality assessment for optical coherence tomography macular scans: a multicentre study

AimsTo develop and externally test deep learning (DL) models for assessing the image quality of three-dimensional (3D) macular scans from Cirrus and Spectralis optical coherence tomography devices.MethodsWe retrospectively collected two...

Case series: Superficial plexus en face may aid distinction of retinal nerve fiber layer loss from diabetic retinal ischemia versus glaucoma.

This study aimed to demonstrate that the pattern and degree of capillary bed dropout in early glaucoma appear different on OCT-A superficial plexus en-face slabs compared with retinal ischemia. RNFL loss associated with retinal ischemia in diabetic patients may be explained and accounted for by overlying the RNFL deviation map on a superficial plexus en-face montage. Three middle-aged White men with diabetes mellitus showed cup-to-disc ratios of approximately 0.7 and RNFL and ganglion thinning. Each patient had several Cirrus OCT and OCT-A scans taken of the posterior pole. The OCT-A en-face images demonstrated specific patterns of superficial capillary dropout. The appearance of superficial plexus capillary dropout in one case of glaucoma is contrasted against two cases of retinal ischemia. Early glaucoma appears to be associated with incomplete capillary bed dropout that extends from macular regions to the disc in a wedge- or arc-shaped pattern. Diabetic retinal ischemia appears to be associated with well-defined patchy and polygonal pockets of complete capillary bed obliteration that may not extend back to the disc. If an RNFL deviation map is superimposed over the superficial plexus en-face montage, areas of RNFL loss may correlate with and thus be well accounted for by areas of retinal ischemia in cases with RNFL thinning likely from ischemia. This approach may supplement inspection of OCT B-scans for focal retinal thinning when trying to differentiate RNFL and ganglion cell loss from retinal ischemia versus glaucoma in patients with diabetes. Formal research studies are needed to validate our observations and proposed use of OCT-A together with OCT in these patients.

The effect of macular visual field test density on central structure-function concordance in glaucoma

ABSTRACT Clinical relevance Central visual field (VF) testing often requires focussed high-density test grids. The critical number of test locations for maximising structure-function concordance in the macula is not known. Purpose The aim of this work is to determine the impact of the number of test locations in the central VF on binarized structure-function concordance in glaucoma. Methods Humphrey Field Analyser (HFA) 10–2 test grid and Cirrus optical coherence tomography Ganglion Cell Analysis (GCA) results from one eye of 155 glaucoma patients were extracted. Following anatomical correction for retinal ganglion cell displacement, the pointwise results of the central 36 locations of the 10–2 pattern deviation map and their corresponding locations within the GCA deviation map were recorded. The number of test locations was systematically reduced from 36 (4 locations per step) and added from 1 (1 location per step) and binarized structure-function concordance (p < 0.05 for both) at each step was evaluated. Eleven test point subtraction and addition models were developed. Concordance rates (proportion) were plotted as a function of number of test locations, and were fitted using segmental nonlinear regression to identify the critical point of inflection at which concordance was maximised and discordance minimised. Results Subtractive and additive approaches returned two-way estimates of the critical number, with, on average 8–14 test locations being the range at which structure-function concordance was optimised in the present cohort across all models. A randomised approach to subtracting or adding test locations returned critical numbers that were similar to systematic and empirical models, suggesting that specific test location was not as critical in optimising structure-function concordance compared to the number of test locations. Conclusion There is a potential critical number (8–14) in macular visual field testing where binarized structure-function concordance is optimised, providing a framework for guiding the development of integrated macular test locations in VF testing for glaucoma.

En Face and Volumetric Comparison of Hypertransmission Defects Evaluated by Cirrus and Spectralis Optical Coherence Tomography

PurposeTo evaluate and compare en face and 3-dimensional (D) properties of hypertransmission defects (HTDs) between different optical coherence tomography (OCT) devices using OCT volumes and reconstructed en face images. SettingsComparative diagnostic evaluation study. MethodsThirty eyes with dry age-related macular degeneration (AMD) that underwent dense OCT macular volume scans with both the Spectralis (97 B-scans/volume; 2,910 B-scans in total) and Cirrus OCT (128 B-scans/volume; 3,840 B-scans in total) from AMISH EYE STUDY cohort were included in this analysis. HTD regions were labeled on each B-scan and reconstructed into en face and 3-D volume images. Properties of HTD volume were compared between the two devices. ResultsQualitative score of en face images for HTD was higher for the Cirrus compared to the Spectralis (P < 0.01). The quality of Spectralis en face images improved after preprocessing and reconstruction. The 2-D HTD area on en face obtained from 2-D projections of 3-D volume did not differ between devices (P = 0.478; ICC 0.998; Jaccard index 0.721 ± 0.086). There was no difference in the number, volume, PALs, and surface areas of HTDs between devices in the volumetric analysis (all P ≥ 0.090). The signal intensity of HTD normalized by the mean choroidal signal intensity did not differ between devices (P = 0.861). ConclusionsThe visualization of HTD on en face images from Spectralis OCT could be enhanced through image processing. The equivalence in 3-D HTD parameters between the two devices suggests interchangeability for assessing these lesions in AMD.

Assessment of linear regression of peripapillary optical coherence tomography retinal nerve fiber layer measurements to forecast glacuoma trajectory.

Linear regression of optical coherence tomography measurements of peripapillary retinal nerve fiber layer thickness is often used to detect glaucoma progression and forecast future disease course. However, current measurement frequencies suggest that clinicians often apply linear regression to a relatively small number of measurements (e.g., less than a handful). In this study, we estimate the accuracy of linear regression in predicting the next reliable measurement of average retinal nerve fiber layer thickness using Zeiss Cirrus optical coherence tomography measurements of average retinal nerve fiber layer thickness from a sample of 6,471 eyes with glaucoma or glaucoma-suspect status. Linear regression is compared to two null models: no glaucoma worsening, and worsening due to aging. Linear regression on the first M ≥ 2 measurements was significantly worse at predicting a reliable M+1st measurement for 2 ≤ M ≤ 6. This range was reduced to 2 ≤ M ≤ 5 when retinal nerve fiber layer thickness measurements were first "corrected" for scan quality. Simulations based on measurement frequencies in our sample-on average 393 ± 190 days between consecutive measurements-show that linear regression outperforms both null models when M ≥ 5 and the goal is to forecast moderate (75th percentile) worsening, and when M ≥ 3 for rapid (90th percentile) worsening. If linear regression is used to assess disease trajectory with a small number of measurements over short time periods (e.g., 1-2 years), as is often the case in clinical practice, the number of optical coherence tomography examinations needs to be increased.

Effects of cataract on peripapillary retinal nerve fibre layer and ganglion cell‐inner plexiform layer thickness measurement by cirrus optical coherence tomography

Aims/Purpose: To assess the effect of cataract on peripapillary retinal nerve fibre layer (pRNFL) thickness and macular ganglion cell‐inner plexiform layer (mGC‐IPL) thickness measured by Cirrus (Carl Zeiss Meditec, Dublin, California, USA) spectral domain–optical coherence tomography (OCT).Methods: Cirrus OCT was used to measure the pRNFL thickness and mGC‐IPL thickness in 44 patients (63 eyes) patients with cataract, including 43 glaucoma eyes. Cataracts were graded according to the Lens Opacities Classification System III. The study aimed to identify factors that could contribute to segmentation errors and variations in the signal strength index (SSI) or average thickness of mGC‐IPL and pRNFL.Results: The prevalence of preoperative segmentation error were higher in pRNFL measurements compared with mGC‐IPL measurements (36.5% vs. 19.0%, p = 0.046). Multivariate analysis showed that segmentation error in RNFL measurements was significantly associated with preoperative SSI. Multivariate analysis indicated that preoperative SSI was highly correlated with changes with average thickness changes of mGC‐IPL and pRNFL.Conclusions: Among eyes with cataract, the occurrence of segmentation errors was more common in measurements of the pRNFL compared to measurements of mGC‐IPL. Following cataract surgery, there was a slight increase in all thickness parameters in both mGC‐IPL and pRNFL measurements, although the differences were not statistically significant (p = 0.102 and p = 0.151, respectively). It is important to identify segmentation errors, particularly in pRNFL measurements of eyes with cataract and low SSI.

Factors associated with retinal nerve fibre layer stability after glaucoma surgery

Aims/Purpose: The first objective of the present study was to investigate whether retinal nerve fibre layer (RNFL) deterioration exists after successful glaucoma surgery, and how long it lasts. The second objective was to identify the factors associated with RNFL thickness stability after surgery.Methods: A retrospective observational study was conducted. A total of 128 eyes of 108 patients who received one successful glaucoma surgery including trabeculectomy and Ahmed valve implantation, and had been followed up with cirrus optical coherence tomography (cOCT) were examined. We defined intraocular pressure (IOP) reduction as the difference between peak IOP before surgery and IOP at the first cOCT examination after surgery. RNFL thickness reduction greater than −5.03 μm/year immediately after surgery, but remained below −5.03 μm/year in two or more consecutive examinations was defined as a ‘maintenance after progression group’ (group1). Also, the other group was defined as a ‘maintenance group’ (group 2), RNFL thickness reduction less than −5.03 μm/year.Results: There was no significant difference between two groups in sex, age, diagnosis, and operation. However, preoperative IOP was statistically significantly higher in group 2 than in group 1 (p = 0.039). There was no significant difference between group 1 and 2 in the duration of IOP elevation before surgery (p = 0.998). The preoperative RNFL thickness tended to be thicker in group 2 than in group 1, but it was not statistically significant. The average duration of progression in group 2 was 23.9 months. Factors containing age, sex, operation, diagnosis, preoperative IOP, preoperative IOP rise duration, and pretreatment RNFL thickness were less relevant with postoperative RNFL thickness reduction stabilization.Conclusions: In conclusion, the factor that showed a significant difference between the ‘maintenance after progression group’ (group 1) and the ‘maintenance group’ (group 2) was preoperative IOP.ReferencesKim WJ, Kim KN, Sung JY, Kim JY, Kim CS. Relationship between preoperative high intraocular pressure and retinal nerve fibre layer thinning after glaucoma surgery. Sci Rep‐Uk 2019, 9.

Comparison of the TEMPO binocular perimeter and Humphrey field analyzer

This study compared between TEMPO, a new binocular perimeter, with the Humphrey Field Analyzer (HFA). Patients were tested with both TEMPO 24–2 Ambient Interactive Zippy Estimated by Sequential Testing (AIZE)-Rapid and HFA 24–2 Swedish Interactive Threshold Algorithm (SITA)-Fast in a randomized sequence on the same day. Using a mixed-effects model, visual field (VF) parameters and reliability indices were compared. Retinal nerve fiber layer (RNFL) thickness was measured using Cirrus optical coherence tomography (OCT), and coefficient of determinations for VF and OCT parameters were calculated and compared using Akaike information criteria. 740 eyes (including 68 healthy, 262 glaucoma suspects, and 410 glaucoma) of 370 participants were evaluated. No significant differences were seen in mean deviation and visual field index between the two perimeters (P > 0.05). A stronger association between VF mean sensitivity (dB or 1/L) and circumpapillary RNFL was found for TEMPO (adjusted R2 = 0.25; Akaike information criteria [AIC] = 5235.5 for dB, and adjusted R2 = 0.29; AIC = 5200.8 for 1/L, respectively) compared to HFA (adjusted R2 = 0.22; AIC = 5263.9 for dB, and adjusted R2 = 0.22; AIC = 5262.7 for 1/L, respectively). Measurement time was faster for TEMPO compared to HFA (261 s vs. 429 s, P < 0.001). Further investigations are needed to assess the long-term monitoring potential of this binocular VF test.

Central macular morphology and optic nerve fibre layer thickness in young adults born premature and screened for retinopathy of prematurity.

To investigate central retinal morphology and optic retinal nerve fibre layer (RNFL) in prematurely born young adults and compare to term born controls. The participants were 59 prematurely born individuals, with a birthweight ≤1.500 g, and 44 term born controls, all 25-29 years of age. Visual acuity (VA) and contrast sensitivity (CS) were assessed. The retinal macular thickness, ganglion cell-inner plexiform layer (GC-IPL) thickness and RNFL thickness were assessed with Cirrus optical coherence tomography (OCT). Central macular thickness was increased (mean 26.7 μm) in prematurely born individuals compared to controls. The macular GC-IPL was thinner (mean 3.84 μm), also when excluding those with previous retinopathy of prematurity (ROP) and those with neurological complications. Gestational age at birth and previous treatment of ROP were risk factors for a thicker macula, however, not for reduced GC-IPL. The average peripapillary RNFL was thinner (mean 4.61 μm) in the prematurely born individuals, also when excluding those with previous ROP and/or neurological complications. Within the prematurely born group, treated ROP was correlated with increased average RNFL. Further, both better VA and CS were associated with thinner optic nerve RNFL and thicker average GC-IPL. Macular and optic nerve morphology were influenced by premature birth as assessed with OCT in adult individuals. Gestational age at birth and treatment for ROP seemed to affect central macular thickness, and treated ROP affected the peripapillary RNFL. Thus, retinal sequelae remained in adulthood.

Artifacts in OCT Retinal Nerve Fiber Layer Imaging in Patients with Boston Keratoprosthesis Type 1

To determine the clinical utility of optical coherence tomography retinal nerve fiber layer (OCT RNFL) imaging for glaucoma evaluation in patients with Boston keratoprosthesis type 1 (KPro) by investigating imaging artifacts. Case-control study. Patients with KPro and without KPro (controls) matched for age, gender, and glaucoma diagnosis. The most recent Cirrus OCT RNFL scan from one eye was categorized as with good signal strength (SS; ≥6 out of 10) or poor SS (<6). Those with good SS were analyzed by two independent reviewers for artifacts. Images with good SS and no artifacts affecting the scanning circle were considered useful for glaucoma evaluation. The incidence of poor SS and artifacts in OCT RNFL images; patient characteristics associated with useful scans. Sixty-five patients with KPro and 75 controls were included; 89.2% of KPro patients and 89.3% of control subjects had glaucoma (p=0.98). 40.0% of KPro patients and 5.3% of controls had poor SS (p<0.001). The proportion of images with either poor SS or artifacts was similar in KPro (76.9%) versus controls (72.0%, p=0.51). The most common artifacts in both groups were missing data (43.6%, 53.2%, respectively, p=0.32) and motion artifact (25.6%, 19.7%, respectively, p=0.47). 43.1% of images in KPro patients and 69.3% in controls were useful for glaucoma evaluation (p=0.002). In the KPro group, patients with useful OCT scans, compared to those without, had better visual acuity (0.4±0.3 vs. 0.9±0.7 LogMAR, p=0.004), and did not have congenital corneal pathologies (0.0% vs. 24.3%, p=0.008). A multivariable analysis showed KPro patients with older age had higher odds of useful OCT images (odds ratio 1.05, p=0.03). Among KPro patients with useful OCT scans, RNFL thickness correlated with observed cup to disc ratio (Pearson correlation r=-0.42, p=0.03). The rate of OCT RNFL images with either poor signal strength or artifacts in the KPro and control population was comparable. In patients with KPro, where intraocular pressure measurements are difficult and glaucoma is highly prevalent and often severe, OCT RNFL imaging can be useful for glaucoma evaluation.

Performance of neuroretinal rim thickness measurement by Cirrus high-definition optical coherence tomography in myopic eyes

Neuroretinal rim (NRR) measurement can aid the diagnosis of glaucoma. A few studies reported that Cirrus optical coherence tomography (OCT) had NRR segmentation errors. The current study investigated segmentation success of NRR in myopic eyes using the Cirrus built-in software and to determine the number of acquisitions required to identify NRR thinning. Right eye of 87 healthy adult myopes had an optic disc scanned using Cirrus HD-OCT for five successive acquisitions. A masked examiner evaluated 36 radial line images of each scan to screen for segmentation errors using the built-in software at the Bruch’s membrane opening (BMO) and/or internal limiting membrane (ILM). Participants with three accurate NRR acquisitions had their average NRR thickness determined. This result was compared with average of the two acquisitions and the first acquisition. Among 435 OCT scans of the optic disc (87 eyes × 5 acquisitions), 129 (29.7%) scans had segmentation errors that occurred mainly at the ILM. The inferior-temporal and superior meridians had slightly more segmentation errors than other meridians, independent of axial length, amount of myopia, or presence of peripapillary atrophy. Sixty-five eyes (74.7%) had at least three accurate NRR measurements. The three acquisitions had high reliability in NRR thickness in the four quadrants (intraclass correlation coefficient > 0.990, coefficient of variation < 3.9%). NRR difference between the first acquisition and the average of three acquisitions was small (mean difference 2 ± 13 μm, 95% limits of agreement within ± 30 μm) among the four quadrants. Segmentation errors in NRR measurements appeared regardless of axial length, amount of myopia, or presence of peripapillary atrophy. Cirrus segmentation lines should be manually inspected when measuring NRR thickness.

Optic Nerve Head Morphology is Associated with the Initial Location of Structural Progression in Early Open-Angle Glaucoma.

To investigate the effects of clinical variables on the temporal relationship between macular ganglion cell-inner plexiform layer (mGCIPL) loss and peripapillary retinal nerve fiber layer (pRNFL) loss in glaucoma. Glaucoma eyes with a small cup-to-disc ratio tend to show retinal nerve fiber layer progression earlier than ganglion cell-inner plexiform layer progression. This retrospective observational study used medical records of patients diagnosed with open-angle glaucoma. Structural change was determined using guided progression analysis software of Cirrus optical coherence tomography. Based on the time of detection of pRNFL and mGCIPL changes, eyes showing progressive layer loss were categorized into the pRNFL-first and mGCIPL-first groups. The association between sites of layer thinning and clinical variables such as major retinal arterial angles and several optic disc measurements including disc area, average cup-to-disc ratio (CDR), and vertical CDR were analyzed. A total of 282 eyes were included in the study, of which 104 showed structural progression either in the mGCIPL or pRNFL. Out of these, 49 eyes showed first progression in pRNFL, while 37 eyes showed first progression in mGCIPL. The minimum mGCIPL thickness, pRNFL thickness, average CDR, vertical CDR, and location of progression were significantly different between the two groups (P=0.041, P=0.034, P=0.015, P<0.001, and P<0.001, respectively). In multivariate analysis, average CDR and vertical CDR were significantly associated with the progression site (P=0.033 and P=0.006, respectively). The structural changes in the inferoinferior area and the superior vulnerability zone were significantly associated with RNFL-first progression (P<0.001 for both). The location of layer loss and CDR are related to the layer where loss is first detected (either pRNFL or mGCIPL) in open-angle glaucoma.

False-positive classification and associated factors in segmented macular layers and retinal nerve fiber layer analysis: Spectralis OCT deviation map study

The rates, patterns and associated factors for false-positive classification of deviation maps by Cirrus optical coherence tomography (OCT) have been reported. However, research on OCT layer-by-layer deviation maps is lacking. We aimed to determine the rates and associated factors for false-positive classification of segmented macular layers and retinal nerve fiber layer (RNFL) deviation maps of Spectralis OCT, and to identify false-positive patterns on segmented macular layers deviation maps. 118 healthy eyes of 118 normal participants who had undergone Spectralis OCT imaging were included. False-positive classification was determined by the area and location of yellow or red color-coded regions on the deviation map. The false-positive rates on the deviation maps were the highest on the ganglion cell layer map, followed by the inner plexiform layer, retinal layer, and RNFL maps. More myopic/less hyperopic refractive error was a factor significantly associated with higher false-positive classification on the RNFL deviation map, and three false-positive patterns were found on the segmented macular layers deviation maps. Spectralis OCT deviation maps should be interpreted carefully to avoid misdiagnosis, especially for eyes with higher degrees of myopic refractive error on the RNFL map, for which purpose, recognizing the characteristic false-positive patterns would be helpful in clinical practice.

COMPARISON OF ONH, MACULA STRUCTURE AND HFA PATTERN IN HIGH MYOPIA AND EMETROPIA EYES WITH/WITHOUT GLAUCOMA

Introduction: Axial length elongation contributes a challenge in myopia eyes due to morphological and visual field abnormalities. OCT instruments do not embed a normative database from high myopia. The study is aimed to compare Cirrus OCT and HFA parameters on high myopia and emetropia with/without glaucoma. Methods: This cross-sectional, prospective study was conducted at Sardjito General Hospital from 1st April 2021 to 11th May 2021. Patients with high myopia was enrolled with Spherical Equivalent (SE) ? -6D, 20 – 55 years of age. All participants underwent a complete ophthalmologic examination. Inclusion criteria: BCVA 20/40 or better, reliable visual field results. Result: From 22 eyes, there were no significant difference of age between high myopia with glaucoma/HMG (n=5), high myopia/HM (n=6), emetropia with glaucoma/EG (n=5), emetropia/E (n=6) with mean age was 36±3.2 y.o and 60% were male with SE -8.5±1.03D. Among ONH parameters, there were no differences between groups. In HMG, HM, EG, E group, median avgRNFL was 85um, 96.5um, 105um, 110um respectively. Thus, median vertical CD is 0.48, 0.40, 0.58, 0.55 in HMG, HM, EG, E group respectively. Whilst median GCIPL and visual index were 75um, 78.5um, 85um, 89.5um in HMG, HM, EG, E group respectively and had significantly different 0.012 (p&lt;0.05) between groups. Median visual field index was 92%, 97%, 98% in HMG, HM, EG group respectively with significantly different 0.04 (p&lt;0.05). Conclusion: The GCIPL and visual field index are significantly different between high myopia and emetropia with/without glaucoma

Comparing the Accuracy of Peripapillary OCT Scans and Visual Fields to Detect Glaucoma Worsening

To compare the accuracy of detecting moderate and rapid rates of glaucoma worsening over a 2-year period with different numbers of OCT scans and visual field (VF) tests in a large sample of glaucoma and glaucoma suspect eyes. Descriptive and simulation study. The OCT sample comprised 12 150 eyes from 7392 adults with glaucoma or glaucoma suspect status followed up at the Wilmer Eye Institute from 2013 through 2021. The VF sample comprised 20 583 eyes from 10 958 adults from the same database. All eyes had undergone at least 5 measurements over follow-up from the Zeiss Cirrus OCT or Humphrey Field Analyzer. Within-eye rates of change in retinal nerve fiber layer (RNFL) thickness and mean deviation (MD) were measured using linear regression. For each measured rate, simulated measurements of RNFL thickness and MD were generated using the distributions of residuals. Simulated rates of change for different numbers of OCT scans and VF tests over a 2-year period were used to estimate the accuracy of detecting moderate (75th percentile) and rapid (90th percentile) worsening for OCT and VF. Accuracy was defined as the percentage of simulated eyes in which the true rate of worsening (the rate without measurement error) was at or less than a criterion rate (e.g., 75th or 90th percentile). The accuracy of diagnosing moderate and rapid rates of glaucoma worsening for different numbers of OCT scans and VF tests over a 2-year period. Accuracy was less than 50% for both OCT and VF when diagnosing worsening after a 2-year period. OCT accuracy was 5 to 10 percentage points higher than VF accuracy at detecting moderate worsening and 10 to 15 percentage points higher for rapid worsening. Accuracy increased by more than 17 percentage points when using both OCT and VF to detect worsening, that is, when relying on either OCT or VF to be accurate. More frequent OCT scans and VF tests are needed to improve the accuracy of diagnosing glaucoma worsening. Accuracy greatly increases when relying on both OCT and VF to detect worsening. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Machine Learning-Based Automated Detection and Quantification of Geographic Atrophy and Hypertransmission Defects Using Spectral Domain Optical Coherence Tomography.

The current study describes the development and assessment of innovative, machine learning (ML)-based approaches for automated detection and pixel-accurate measurements of regions with geographic atrophy (GA) in late-stage age-related macular degeneration (AMD) using optical coherence tomography systems. 900 OCT volumes, 100266 B-scans, and en face OCT images from 341 non-exudative AMD patients with or without GA were included in this study from both Cirrus (Zeiss) and Spectralis (Heidelberg) OCT systems. B-scan and en face level ground truth GA masks were created on OCT B-scan where the segmented ellipsoid zone (EZ) line, retinal pigment epithelium (RPE) line, and bruchs membrane (BM) line overlapped. Two deep learning-based approaches, B-scan level and en face level, were trained. The OCT B-scan model had detection accuracy of 91% and GA area measurement accuracy of 94%. The en face OCT model had detection accuracy of 82% and GA area measurement accuracy of 96% with primary target of hypertransmission on en face OCT. Accuracy was good for both devices tested (92-97%). Automated lesion size stratification for CAM cRORA definition of 250um minimum lesion size was feasible. High-performance models for automatic detection and segmentation of GA area were achieved using OCT systems and deep learning. The automatic measurements showed high correlation with the ground truth. The en face model excelled at identification of hypertransmission defects. The models performance generalized well across device types tested. Future development will include integration of both models to enhance feature detection across GA lesions as well as isolating hypertransmission defects without GA for pre-GA biomarker extraction.

Systematic detection of keratoconus in OCT: corneal and epithelial thickness maps.

To detect keratoconus (KC) only by analyzing the corneal and epithelial map parameters and patterns in optical coherence tomography (OCT). Tertiary care refractive surgery center. Retrospective data collection. Corneal and epithelial thickness maps of normal, manifest, and subclinical keratoconic eyes (according to the Belin-Ambrosio display, Pentacam) were evaluated using spectral-domain OCT (Zeiss Cirrus 5000 HD). A new 2-step decision tree was developed based on previous studies with another OCT device. In the first step, if at least 1 of the 4 independent parameters (pachymetry minimum, pachymetry minimum-median, pachymetry superonasal-inferotemporal, and epithelial superonasal-inferotemporal) overruns the cutoff values, the eye was suspicious for KC. In the second step, if the epithelial map showed concentric thinning and the thinnest point of the cornea and epithelium is coincident, the eye was classified as keratoconic. 172 manifest keratoconic eyes (108 patients), 21 subclinical keratoconic eyes (20 patients), and 172 normal eyes (90 age-matched participants) were included in this study. Step 1 captured 100% of manifest and subclinical keratoconic eyes. Step 2 ruled out all suspicious but normal cases and, falsely, 2 subclinical keratoconic eyes. Our 2-step decision tree reached 100% specificity, 100% sensitivity in manifest KC, and 90.4% sensitivity in subclinical KC. Pachymetric and epithelial map parameters and patterns in OCT can be used in the diagnosis of KC, including subclinical cases, yielding a high level of agreement with the commonly used diagnostic reference, the Belin-Ambrosio display. Further improvements by refining our algorithm and including an automated evaluation in the software are desirable.

Visible Light Optical Coherence Tomography of Peripapillary Retinal Nerve Fiber Layer Reflectivity in Glaucoma.

PurposeTo evaluate the clinical utility of visible light optical coherence tomography (VIS-OCT) and to test whether VIS-OCT reflectivity and spectroscopy of peripapillary retinal nerve fiber layer (pRNFL) are correlated with severity of glaucoma, compared with standard-of-care OCT thickness measurements.MethodsIn total 54 eyes (20 normal, 17 suspect/preperimetric glaucoma [GS/PPG], 17 perimetric glaucoma [PG]) were successfully imaged with complete datasets. All the eyes were scanned by a custom-designed dual-channel device that simultaneously acquired VIS-OCT and near-infrared OCT (NIR-OCT) images. A 5 × 5 mm2 scan was taken of the pRNFL. The pRNFL reflectivity was calculated for both channels and the spectroscopic marker was quantified by pVN, defined as the ratio of VIS-OCT to NIR-OCT pRNFL reflectivity. The results were compared with ophthalmic examinations and Zeiss Cirrus OCT.ResultsVIS-OCT pRNFL reflectivity significantly, sequentially decreased from normal to GS/PPG to PG, as did NIR-OCT pRNFL reflectivity. The pVN had the same decreasing trend among three groups. Normal and GS/PPG eyes were significantly different in VIS-OCT pRNFL reflectivity (P = 0.002) and pVN (P < 0.001), but were not in NIR-OCT pRNFL reflectivity (P = 0.14), circumpapillary RNFL thickness (P = 0.17), or macular ganglion cell layer and inner plexiform layer thickness (P = 0.07) in a mixed linear regression model.ConclusionsVIS-OCT pRNFL reflectivity and pVN better distinguished GS/PPG from normal eyes than Cirrus OCT thickness measurements.Translational RelevanceVIS-OCT pRNFL reflectivity and pVN could be useful metrics in the early detection of glaucoma upon further longitudinal validation.

Ganglion cell inner plexiform layer thickness measured by optical coherence tomography to predict visual outcome in chiasmal compression

We evaluated the prognostic value of the preoperative macular ganglion cell inner plexiform layer (mGCIPL) thickness along with peripapillary retinal nerve fiber layer (pRNFL) thickness measured by optical coherence tomography (OCT) and estimated an optimal cut-off value to predict postoperative visual field (VF) recovery in adult patients with chiasmal compression after decompression surgery. Two hundred forty eyes of 240 patients aged 20 years or older for which preoperative high-definition Cirrus OCT parameters and pre- and postoperative visual function data were available. The prognostic power of pRNFL and mGCIPL thicknesses for complete postoperative VF recovery or significant VF improvement (improvement ≥ 2 dB in the mean deviation) were assessed. The cut-off values for OCT parameters for VF recovery were estimated. The study found that the higher the preoperative pRNFL and mGCIPL thicknesses, the higher the probability of complete postoperative VF recovery (p = 0.0378 and p = 0.0051, respectively) or significant VF improvement (p = 0.0436 and p = 0.0177, respectively). The area under the receiver operating characteristic analysis of preoperative OCT parameters demonstrated that the mGCIPL thickness showed an area under the curve (AUC) of more than 0.7 for complete VF recovery after decompression surgery (AUC = 0.725, 95% CI: 0.655, 0.795), and the optimal mGCIPL thickness cut-off value for complete VF recovery was 77.25 µm (sensitivity 69% and specificity 69%). Preoperative mGCIPL thickness was a powerful predictor of visual functional outcome after decompression surgery for chiasmal compression.

Clinical usefulness of layer-by-layer deviation maps of Spectralis OCT: comparison with Cirrus OCT

Background/aimsTo compare the diagnostic abilities of Spectralis (Heidelberg Engineering, Heidelberg, Germany) and Cirrus (Carl Zeiss Meditec, Dublin, California, USA) spectral domain–optical coherence tomography (OCT) for retinal nerve fibre layer (RNFL)...