Optical Coherence Tomography In Glaucoma Research Articles

Evaluation of optical coherence tomography findings in patients with multiple sclerosis and glaucoma.

Glaucoma and multiple sclerosis (MS) can cause optic disc pathology and, in this way, affect optical coherence tomography (OCT) data. In this context, the objective of this study is to investigate the changes in the mean, quadrant, and sector data measured by OCT in glaucoma and MS patients. The sample of this prospective cohort study consisted of 42 MS patients (84 eyes), 34 Primary open-angle glaucomas patients (67 eyes), and 24 healthy control subjects (48 eyes). The MS group was divided into two groups according to the presence of a history of optic neuritis. Accordingly, those with a history of optic neuritis were included in the MS ON group, and those without a history of optic neuritis were included in the MS NON group. The differences between these groups in the mean, quadrant, and sector data related to the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) were evaluated. Superior nasal (SN), superior temporal (ST), inferior nasal (IN), and superior quadrant (SUP) values were significantly lower in the glaucoma group than in the MS group (p < 0.05). The mean superior GCC (GCC SUP) value was significantly lower in the MS ON group than in the glaucoma group (p < 0.05). On the other hand, SN, ST, inferior temporal (IT), IN, average RNFL (AVE RNFL), semi-average superior RNFL (SUP AVE RNFL), semi-average inferior RNFL (INF AVE RNFL), SUP, and inferior quadrant RNFL (INF) values were significantly lower in the glaucoma group than in the MS NON group (p < 0.05). RNFL and GCC parameters get thinner in MS and glaucoma patients. While the inferior and superior RNFL quadrants are more frequently affected in glaucoma patients, the affected quadrants vary according to the presence of a history of optic neuritis in MS patients. It is noteworthy that the GCC superior quadrant was thin in MS ON patients. The findings of this study indicate that OCT data may be valuable in the differential diagnosis of glaucoma and MS.

Racial-ethnic disparities in concurrent rates of peripapillary & macular OCT parameters among a large glaucomatous clinical population.

To compare rates of change in peripapillary retinal nerve fibre layer (pRNFL) and macular ganglion cell-inner plexiform layer (mGCIPL) parameters among different race-ethnicities from a large electronic health record database of subjects with or suspected of glaucoma. In this retrospective cohort study, rates of change were obtained using joint longitudinal linear mixed models for eyes with ≥3 visits and ≥1 year of follow-up, adjusting for age, sex, intraocular pressure, central corneal thickness, and baseline pRNFL and mGCIPL thickness. Best linear unbiased predictor estimates of various parameters were stratified by baseline glaucoma severity and analysed by racial-ethnic group. A total of 21,472 spectral domain optical coherence tomography (OCT) pRNFL scans and 14,431 mGCIPL scans from 2002 eyes were evaluated. A total of 200 (15.6%) and 601 (46.8%) subjects identified as non-Hispanic Black (NHB) and Hispanic, respectively. NHB eyes exhibited faster rates of change in pRNFL among glaucoma suspect (global pRNFL -0.57 ± 0.55 µm/year vs. -0.37 ± 0.62 µm/year among Hispanics, p < 0.001), mild glaucoma (superior pRNFL quadrant -1.20 ± 1.06 µm/year vs. -0.75 ± 1.51 µm/year among non-Hispanic Whites (NHW), p = 0.043), and moderate glaucoma eyes (superior pRNFL quadrant -1.31 ± 1.49 µm/year vs. -0.52 ± 1.26 µm/year among Hispanics, p = 0.003). NHB eyes exhibited faster rates of mGCIPL loss corresponding to pRNFL rates. Global pRNFL and mGCIPL rates were strongly correlated (R2 = 0.70). Adjusted rates of pRNFL and mGCIPL loss significantly differed between racial-ethnic groups when stratified by glaucoma severity, with faster rates among NHB patients. These differences highlight key racial-ethnic disparities in adjusted rates of glaucoma OCT parameters.

From the past to the present, optical coherence tomography in glaucoma: a practical guide to a common disease.

Glaucoma comprises a group of disorders of the optic nerve that cause degenerative optic neuropathy, characterised by failure of neuroretinal rim tissue in the optic nerve head, retinal nerve fibre layer, and retinal ganglion cells. Glaucoma imposes a serious epidemiological threat, with an steady increase in the global number of cases. In the current ophthalmological practice, glaucoma is diagnosed via a series of examinations, including routine funduscopic examination, ocular tonometry, gonioscopy, measurement of the visual field, and assessment using the optical coherence tomography (OCT) technique. Nowadays, the OCT technique helps in systematising the diagnostic pathway and is a basic diagnostic tool for detection of early glaucomatous eye changes. It is also vital in assessing progression and monitoring treatment results of patients. The aim of this review was to present the OCT technique as a main tool in diagnosing and monitoring glaucoma.

Individual vs simultaneous macular and optic disc measurements with spectral domain optical coherence tomography in glaucoma and healthy eyes

We assessed the repeatability and agreement of ganglion cell complex (GCC) in the macular area and the peripapillary retinal nerve fiber layer (ppRNFL) with individual and combined macula and disc scans. The macular GCC and ppRNFL thicknesses from 34 control eyes and 43 eyes with glaucoma were measured with the Canon Optical Coherence Tomography (OCT) HS-100. Two repeated measurements were performed with both scan modes. The repeatability limit (Rlim) and agreement analysis were performed. The individual scan showed better repeatability than the combined scan in both groups. However, the differences in the Rlim for the GCC in most sectors were lower than 3 μm (axial resolution of the OCT), and this was larger than 3 μm for most of the ppRNFL sectors. The mean differences in the thickness between both scan modes for the GCC and ppRNFL measurements were less than 3 and 6 μm, respectively. The interval of the limits of agreement was about 10 μm in some sectors for the GCC, and about 40 and 60 μm in some sectors in controls and glaucoma eyes, respectively. Both scan modes showed good repeatability in both groups. The agreement results suggest that the scan modes cannot be used interchangeably.

Structure-function relationship and diagnostic value of macular ganglion cell complex measurement using Fourier-domain OCT in glaucoma.

To evaluate the relationship between visual function and macular ganglion cell complex (GCC) thickness measured by Fourier-domain optical coherence tomography (OCT) and evaluate the diagnostic value of GCC measurement compared to retinal nerve fiber layer (RNFL) thickness and macular thickness in detecting early, moderate, and severe glaucomas. Subjects underwent standard automated perimetry (SAP), OCT imaging with optic nerve head mode and GCC mode. The relationship between OCT parameters (mean GCC thickness, mean RNFL thickness, and macular thickness) and perimetry global indices (mean deviation [MD] and pattern standard deviation [PSD]) was evaluated by regression analysis. Diagnostic values of mean RNFL thickness, GCC parameters, and macular thickness were compared with the area under the receiver operating characteristic curves (AUC). A total of 84 eyes, 42 of each normal and primary open-angle glaucoma patients were included in the study. Compared with linear models, second-order polynomial models better described relationships between GCC thickness and MD ( P < 0.001), and between GCC thickness and PSD ( P = 0.00). RNFL parameter, inferior RNFL thickness had the highest AUC for detecting early glaucoma. The AUC of mean GCC thickness for early glaucoma was higher than that of mean RNFL; however, the difference was not significant ( P = 0.09), which was higher than that of macular thickness. The relationship between visual field (VF) sensitivity and GCC thickness is best expressed by the curvilinear function. Macular GCC thickness and RNFL thickness showed similar diagnostic values but were better than macular thickness for detecting early glaucoma but inferior to macular thickness and RNFL thickness for detecting moderate glaucoma.

Extracting decision-making features from the unstructured eye movements of clinicians on glaucoma OCT reports and developing AI models to classify expertise.

This study aimed to investigate the eye movement patterns of ophthalmologists with varying expertise levels during the assessment of optical coherence tomography (OCT) reports for glaucoma detection. Objectives included evaluating eye gaze metrics and patterns as a function of ophthalmic education, deriving novel features from eye-tracking, and developing binary classification models for disease detection and expertise differentiation. Thirteen ophthalmology residents, fellows, and clinicians specializing in glaucoma participated in the study. Junior residents had less than 1 year of experience, while senior residents had 2-3 years of experience. The expert group consisted of fellows and faculty with over 3 to 30+ years of experience. Each participant was presented with a set of 20 Topcon OCT reports (10 healthy and 10 glaucomatous) and was asked to determine the presence or absence of glaucoma and rate their confidence of diagnosis. The eye movements of each participant were recorded as they diagnosed the reports using a Pupil Labs Core eye tracker. Expert ophthalmologists exhibited more refined and focused eye fixations, particularly on specific regions of the OCT reports, such as the retinal nerve fiber layer (RNFL) probability map and circumpapillary RNFL b-scan. The binary classification models developed using the derived features demonstrated high accuracy up to 94.0% in differentiating between expert and novice clinicians. The derived features and trained binary classification models hold promise for improving the accuracy of glaucoma detection and distinguishing between expert and novice ophthalmologists. These findings have implications for enhancing ophthalmic education and for the development of effective diagnostic tools.

From the past to the present, optical coherence tomography in glaucoma: a practical guide to a common disease

Glaucoma comprises a group of disorders of the optic nerve that cause degenerative optic neuropathy, characterised by failure of neuroretinal rim tissue in the optic nerve head, retinal nerve fibre layer, and retinal ganglion cells. Glaucoma imposes a serious epidemiological threat, with an steady increase in the global number of cases. In the current ophthalmological practice, glaucoma is diagnosed via a series of examinations, including routine funduscopic examination, ocular tonometry, gonioscopy, measurement of the visual field, and assessment using the optical coherence tomography (OCT) technique. Nowadays, the OCT technique helps in systematising the diagnostic pathway and is a basic diagnostic tool for detection of early glaucomatous eye changes. It is also vital in assessing progression and monitoring treatment results of patients. The aim of this review was to present the OCT technique as a main tool in diagnosing and monitoring glaucoma.

Dynamic Ranges of Retinal Nerve Fiber and Optic Nerve Head Parameters Measured Using Optical Coherence Tomography in Glaucoma: A Longitudinal Study.

To evaluate the dynamic range of retinal nerve fiber layer (RNFL) and optic nerve head (ONH) parameters measured using optical coherence tomography (OCT) in conditions ranging from nonglaucomatous status to advanced glaucoma by longitudinal observation. A total of 15 eyes from 12 participants with glaucoma progression from a nonglaucomatous status to advanced glaucoma were included. The RNFL and ONH parameters were compared between the nonglaucomatous and advanced stages within the same eye. The absolute and relative changes in OCT parameters were analyzed. The median highest intraocular pressure was 42.5 mmHg (interquartile range, 37.5 to 54.5 mmHg), and the final mean deviation of the visual field test was -24.68 dB (interquartile range, -23.93 to -31.13 dB). The median relative changes in RNFL thickness were -40.6% in the overall area, and -51.9%, -21.4%, -51.1%, and -41.8% in the superior, nasal, inferior, and temporal quadrants, respectively (all p < 0.05). Relative changes in the rim area, disc area, average cup to disc ratio, vertical cup to disc ratio, and cup volume were -56.64%, 0.59%, 62.10%, 66.0%, and 337.90%, respectively (all p < 0.05, except for disc area with a p-value of 0.753). The dynamic range of the RNFL thickness ranged from 40.6% to 51.9%, and the dynamic range of the ONH parameters ranged from 56.64% to 337.90%. During the course of glaucoma progression, the cup volume showed the widest dynamic range. However, the disc area did not show significant changes.

Deep learning and optical coherence tomography in glaucoma: Bridging the diagnostic gap on structural imaging

Glaucoma is a leading cause of progressive blindness and visual impairment worldwide. Microstructural evidence of glaucomatous damage to the optic nerve head and associated tissues can be visualized using optical coherence tomography (OCT). In recent years, development of novel deep learning (DL) algorithms has led to innovative advances and improvements in automated detection of glaucomatous damage and progression on OCT imaging. DL algorithms have also been trained utilizing OCT data to improve detection of glaucomatous damage on fundus photography, thus improving the potential utility of color photos which can be more easily collected in a wider range of clinical and screening settings. This review highlights ten years of contributions to glaucoma detection through advances in deep learning models trained utilizing OCT structural data and posits future directions for translation of these discoveries into the field of aging and the basic sciences.

Prediction of visual field defects from macular optical coherence tomography in glaucoma using cluster analysis.

PurposeTo assess the accuracy of cluster analysis‐based models in predicting visual field (VF) defects from macular ganglion cell‐inner plexiform layer (GCIPL) measurements in glaucomatous and healthy cohorts.MethodsGCIPL measurements were extracted from posterior pole optical coherence tomography (OCT), from locations corresponding to central VF test grids. Models incorporating cluster analysis methods and corrections for age and fovea to optic disc tilt were developed from 493 healthy participants, and 5th and 1st percentile limits of GCIPL thickness were derived. These limits were compared with pointwise 5th and 1st percentile limits by calculating sensitivities and specificities in an additional 40 normal and 37 glaucomatous participants, as well as applying receiver operating characteristic (ROC) curve analyses to assess the accuracy of predicting VF results from co‐localised GCIPL measurements.ResultsClustered models demonstrated globally low sensitivity, but high specificity in the glaucoma cohort (0.28–0.53 and 0.77–0.91, respectively), and high specificity in the healthy cohort (0.91–0.98). Clustered models showed similar sensitivities and superior specificities compared with pointwise methods (0.41–0.65 and 0.71–0.98, respectively). There were significant differences in accuracy between clusters, with relatively poor accuracy at peripheral macular locations (p < 0.0001 for all comparisons).ConclusionsCluster analysis‐based models incorporating age correction and holistic consideration of fovea to optic disc tilt demonstrated superior performance in predicting VF results to pointwise methods in both glaucomatous and healthy eyes. However, relatively low sensitivity and poorer performance at the peripheral macula indicate that OCT in isolation may be insufficient to predict visual function across the macula accurately. With modifications to criteria for abnormality, the concepts suggested by the described normative models may guide prioritisation of VF assessment requirements, with the potential to limit excessive VF testing.

Correlation of Measurements From Doppler Ultrasound and Optical Coherence Tomography in Glaucoma.

To relate the changes in ocular structure and hemodynamic response in primary open-angle glaucoma (POAG). Patients with POAG (n=46) and control subjects (n=53) were recruited. Retinal nerve fiber layer and ganglion cell complex were evaluated using optical coherence tomography (OCT). Blood flow was characterized in ophthalmic artery (OA) and central retinal artery (CRA) using color Doppler ultrasonography (CDU), and resistivity index (RI) was calculated. Measurements from CDU and OCT were statistically correlated and the degree of the association was examined. Receiver operating characteristics was produced based on RI and optimal threshold was determined. In POAG patients, OCT revealed neuronal damage and CDU indicated increased resistance to arterial flow. Flow dynamics correlated negatively with the ocular tissue dimensions, sufficiently establishing an association between the ocular structure and its hemodynamic response. Based on the possibility of indirect POAG diagnosis with CDU, threshold 0.7 for RI of OA yielded 73.9% sensitivity and 77.4% specificity in distinguishing the cases of POAG from the controls. Threshold of 0.66 for RI of CRA, had higher specificity of 83%, but lower sensitivity of 52.1%. Ocular flow exhibits different characteristics in individuals with POAG than normal. The changes associated with the underlying neuronal structure, suggesting the possibility of a potential new diagnostic biomarker for POAG. This justifies further studies with a larger cohort, examining the ocular flow with CDU in POAG and comparing it against OCT findings for establishing the power of CDU in differential diagnosis or glaucoma progression.

Recent developments in the use of optical coherence tomography for glaucoma.

The aim of this article is to summarize findings of recent reports highlighting the utility of novel optical coherence tomography (OCT) parameters in the diagnosis and monitoring of glaucomatous optic neuropathy. Optic nerve head (ONH), retinal nerve fiber layer (RNFL), and macular parameters show high levels of diagnostic capability. The Bruch's membrane opening-minimum rim width (BMO-MRW) measurement is a novel ONH parameter obtained using the Spectralis SD-OCT device (Heidelberg Engineering, Inc., Heidelberg, Germany). The inferotemporal BMO-MRW sector shows the highest diagnostic performance for this parameter. Minimum ganglion cell and inner plexiform layer thickness shows the highest diagnostic performance among macular parameters obtained with the Cirrus HD-OCT (Carl Zeiss, Inc., Dublin, CA, USA). Optic nerve head, macular, and retinal nerve fiber layer parameters are not interchangeable across protocols generated by varying OCT manufacturers. Novel machine-learning algorithms show promise with regards to achieving higher levels of diagnostic accuracy using OCT imaging platforms. Digital imaging in glaucoma continues to evolve with novel parameters of the optic nerve head, retinal nerve fiber layer, and macula. Diagnostic abilities of these parameters are high and complementary to each other.

Diagnostic performance of multifocal photopic negative response, pattern electroretinogram and optical coherence tomography in glaucoma

The photopic negative response of the electroretinogram reflects retinal ganglion cell function and consequently aids diagnosis of optic nerve diseases including glaucoma. In this study, we assessed the efficacy of stimulation parameters for electroretinographic recordings of the multifocal photopic negative response (mfPhNR) for the detection of glaucoma and compared the diagnostic accuracy of electrophysiological, structural and functional measures of glaucoma. We compared the diagnostic performance of the mfPhNR for 6 different stimulation rates in a cohort of 24 controls, 10 glaucoma suspects (GLAS ) and 16 glaucoma participants (GLAG). A cross-modal comparison of the mfPhNR/b wave ratio was performed with the pattern electroretinogram (PERG), and the peripapillary retinal nerve fiber layer (pRNFL) thickness. These analyses were based on area under curves (AUC) obtained from receiver-operating-characteristics (ROC) and step-wise regression analyses. We found that compared to the other mfPhNR-conditions, the PhNR/b-wave ratio for the fastest stimulation condition had the highest AUC for GLAS (0.84, P = 0.008, 95%CI: 0.71- 0.98), while the other modalities, i.e., PERG-amplitude and pRNFL had AUCs of 0.78 (P= 0.039), and 0.74 (P < 0.05), respectively. For GLAG , the respective AUCs were 0.78 (P= 0.004), 0.85 (P< 0.001) and 0.87 (P< 0.001). pRNFL was the significant predictor for both mfPhNR/b-wave ratio [t (48) = 4, P = 0.0002] and for PERG amplitude [t (48) = 3.4, P = 0.001]. In conclusion, fast mfPhNR protocols outperform other multifocal PhNR protocols in the identification of glaucomatous damage especially for GLAS and thus aid the early detection of glaucoma, indicating its value as a surrogate marker of early stage ganglion cell dysfunction.

Towards multi-center glaucoma OCT image screening with semi-supervised joint structure and function multi-task learning.

Glaucoma is the leading cause of irreversible blindness in the world. Structure and function assessments play an important role in diagnosing glaucoma. Nowadays, Optical Coherence Tomography (OCT) imaging gains increasing popularity in measuring the structural change of eyes. However, few automated methods have been developed based on OCT images to screen glaucoma. In this paper, we are the first to unify the structure analysis and function regression to distinguish glaucoma patients from normal controls effectively. Specifically, our method works in two steps: a semi-supervised learning strategy with smoothness assumption is first applied for the surrogate assignment of missing function regression labels. Subsequently, the proposed multi-task learning network is capable of exploring the structure and function relationship between the OCT image and visual field measurement simultaneously, which contributes to classification performance improvement. It is also worth noting that the proposed method is assessed by two large-scale multi-center datasets. In other words, we first build the largest glaucoma OCT image dataset (i.e., HK dataset) involving 975,400 B-scans from 4,877 volumes to develop and evaluate the proposed method, then the model without further fine-tuning is directly applied on another independent dataset (i.e., Stanford dataset) containing 246,200 B-scans from 1,231 volumes. Extensive experiments are conducted to assess the contribution of each component within our framework. The proposed method outperforms the baseline methods and two glaucoma experts by a large margin, achieving volume-level Area Under ROC Curve (AUC) of 0.977 on HK dataset and 0.933 on Stanford dataset, respectively. The experimental results indicate the great potential of the proposed approach for the automated diagnosis system.

Comparison of Short- And Long-Term Variability in Standard Perimetry and Spectral Domain Optical Coherence Tomography in Glaucoma

To assess short- and long-term variability on standard automated perimetry (SAP) and spectral domain optical coherence tomography (SD-OCT) in glaucoma. Prospective cohort. Ordinary least squares linear regression of SAP mean deviation (MD) and SD-OCT global retinal nerve fiber layer (RNFL) thickness were fitted over time for sequential tests conducted within 5weeks (short-term testing) and annually (long-term testing). Residuals were obtained by subtracting the predicted and observed values, and each patient's standard deviation (SD) of the residuals was used as a measure of variability. Wilcoxon signed-rank test was performed to test the hypothesis of equality between short- and long-term variability. A total of 43 eyes of 43 glaucoma subjects were included. Subjects had a mean 4.5 ± 0.8 SAP and OCT tests for short-term variability assessment. For long-term variability, the same number of tests were performed and results annually collected over an average of 4.0 ± 0.8 years. The average SD of the residuals was significantly higher in the long-term than in the short-term period for both tests: 1.05 ± 0.70 dB vs. 0.61 ± 0.34 dB, respectively (P < 0.001) for SAP MD and 1.95 ± 1.86μm vs. 0.81 ± 0.56μm, respectively (P < 0.001) for SD-OCT RNFL thickness. Long-term variability was higher than short-term variability on SD-OCT and SAP. Because current event-based algorithms for detection of glaucoma progression on SAP and SD-OCT have relied on short-term variability data to establish their normative databases, these algorithms may be underestimating the variability in the long-term and thus may overestimate progression over time.

Influence of Epiretinal Membranes on the Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography in Glaucoma.

PurposeWe investigated changes in the thickness of the peripapillary retinal nerve fiber layer (RNFL) following the onset of an epiretinal membrane (ERM) in glaucoma patients.MethodsAmong regularly monitored glaucoma patients, patients with a newly diagnosed ERM were consecutively enrolled. Before and after the onset of ERM, the RNFL thickness was measured using spectral domain optical coherence tomography, and a visual field examination was performed using a Humphrey field analyzer. Changes in RNFL thickness parameters and global indices of the visual field analyzer were assessed.ResultsIn a total of 28 eyes from 28 patients, the average RNFL thickness increased by a mean of 4.0 ± 7.4 µm (p = 0.009) after ERM onset. There was an increase in the superior, nasal, and temporal quadrant RNFL thicknesses, and the change in the temporal RNFL thickness was significant (14.4 ± 21.2 µm, p < 0.001). However, the inferior RNFL thickness decreased by −0.6 ± 7.5 µm (p = 0.116). In the visual field examination, the mean deviation decreased significantly by −0.8 ± 1.7 dB (p = 0.038), from −14.6 to −15.4 dB.ConclusionsA significant increase in average RNFL thickness was detected following ERM onset in glaucoma patients, although there was deterioration of the mean deviation in the visual field. When ERM occurs in glaucoma patients, clinicians should be aware that RNFL thickness measurements obtained with a spectral domain optical coherence tomography may underestimate the status of glaucomatous optic neuropathy.

Applications of optical coherence tomography in glaucoma

The article reviews literature on optical coherence tomography (OCT) - one of the modern methods of early diagnostics of primary open-angle glaucoma, which has won great popularity among Russian and foreign ophthalmologists. In addition to a summary of the history of the emergence and development of this method, the main purpose was to compare the investigation results and the analysis of the optic disc as the main target subjected to pathological alterations in glaucoma development. Most of the studies comparing the diagnostic capabilities of OCT and Heidelberg retinal tomography (HRT) in the early detection of glaucoma show equivalence of these methods. On the other hand, OCT allows performing subtler structural analysis of the retina, whereas HRT provides more accurate analysis of internal parameters of the optic disc.

Circumpapillary structure-function relationships with microperimetry and spectral domain optical coherence tomography in glaucoma: a pilot study.

PurposeTo compare the relationships between circumpapillary microperimetry (MP)-sensitivity measurements and various circumpapillary retinal thickness parameters in healthy and primary open-angle glaucoma (POAG) eyes.MethodsIn 14 eyes of 14 healthy subjects and 22 early–moderate POAG eyes of 22 patients, circumpapillary optical coherence tomography thickness measurements (RS-3000 Advance OCT, NIDEK) of the retinal nerve fiber layer (cpRNFL), total retina (cpTR), and ganglion cell complex (cpGCC) and outer retina (cpOR) and circumpapillary MP-sensitivity measurements (MP-3 microperimeter, NIDEK) were made in 12 sectors of identical circumpapillary circles. The structure-function relationship was investigated in each sector.ResultsStatistically significant correlations with circumpapillary MP-sensitivity values were found for cpRNFL in five sectors, cpTR in nine sectors, cpGCC in nine sectors, and cpOR in three sectors. The structure-function relationship was strong (r=0.4–0.69) in three sectors for cpRNFL, in six for cpTR, in four for cpGCC, and in one for cpOR. The relationship was very strong (r>0.7) in one sector for cpRNFL, cpTR, and cpGCC, and in no sectors for cpOR. The very strong relationships all occurred in sector 5 (inferotemporal sector).ConclusionIn our pilot study, the circumpapillary structure-function relationship was more extensive for cpTR thickness and cpGCC thickness than for cpRNFL thickness, which suggests that the former parameters may require greater attention in structure-function research into glaucoma.

Research progress of measurement of retinal ganglion cell complex using optical coherence tomography in glaucoma

Glaucoma mainly affects the axon and cell body of retinal ganglion cells (RGCs). Optical coherence tomography (OCT) is a kind of imaging machine with noncontact, high scanning speed and high resolution, can be used for quantitative measurement of retinal ganglion cell complex (GCC) thickness or ganglion cell-inner layer (GCIPL) thickness.GCC includes nerve fiber layer, ganglion cell layer and inner cluster layer, GCIPL only includes ganglion cell layer and inner cluster layer time domain OCT (TD-OCT) can only measure the total thickness of the macular region, in fact, some levels are not involved in the progress of glaucoma, which leads to a decrease in specificity and sensitivity.At present, spectral domain OCT (SD-OCT) is used for measuring GCC and GCIPL.It gains faster scanning speed than traditional TD-OCT, and can scan more locations and form 3D images in macular region.Therefore, it is helpful to improve the sensitivity and specificity of detecting the damage of glaucoma by refining the stratification of the macular retina and making the qualitative measurement of the inner layer of retina.Three scanning modes and methods are commonly used, RTVue-100 OCT, Cirrus HD-OCT, 3D OCT, and the three methods have their own advantages.Measurement of the thickness of GCC by OCT may be influenced by factors such as age, sex, axial length, race and signal intensity.In recent years, many studies have indicated that GCC or GCIPL has a good consistency with the visual field, and can be used in early diagnose and regular follow-up of glaucoma.The future research should be devoted to normal database establishment of GCC and GCIPL thickness parameters with different age and different ethnic and clinical trials and follow-up study should be performed to explore the change rules of those paremeters. Key words: Optical coherence tomography; Retinal ganglion cell complex; Visual field; Glaucoma

Effect of the Eye Tracking System on the Reproducibility of Measurements Obtained With Spectral-domain Optical Coherence Tomography in Glaucoma.

The purpose of this study was to evaluate whether the eye tracking system (ETS) improved the reproducibility of a single circle peripapillary retinal nerve fiber layer (RNFL) measurement acquired with spectral-domain optical coherence tomography (OCT). The sample comprised 205 individuals divided into 2 groups according to intraocular pressure and visual field outcomes. A total of 100 healthy individuals and 105 patients with open-angle glaucoma underwent imaging of the optic nerve head with OCT 3 times during the same session and 2 additional times in subsequent sessions (30 days apart). Intraclass correlation coefficient (ICC), coefficient of variation, and test-retest variability were calculated for the RNFL thickness acquired with and without the ETS enabled, and compared. The glaucoma group mainly comprised patients with moderate glaucoma (mean deviation of standard automated perimetry, -6.73±6.2 dB). The RNFL thicknesses did not differ between acquisitions with or without the ETS activated and disabled. All ICCs were >0.9 in the control and glaucoma groups with or without the ETS activated. The best parameter in the intersession analysis (with ETS activated) was global RNFL thickness (ICC, 0.95; coefficient of variation, 2.7%; and test-retest variability, 2.87 μm). The reproducibility and repeatability of RNFL measurements did not differ significantly between acquisitions with or without the ETS in either group. The reproducibility of peripapillary RNFL thicknesses acquired with OCT was excellent. The variability between OCT measurements did not decrease with the ETS activated.