Comparison Between Deviation Map Algorithm and Peripapillary Retinal Nerve Fiber Layer Measurements Using Cirrus HD-OCT in the Detection of Localized Glaucomatous Visual Field Defects

Genetic Risk of Cardiovascular Disease Is Associated with Macular Ganglion Cell-Inner Plexiform Layer Thinning in an Early Glaucoma Cohort

PURPOSE

To evaluate the association between genetic risk for cardiovascular disease and retinal thinning in early glaucoma.

DESIGN

Prospective, observational genetic association study.

PARTICIPANTS

Multicohort study combining a cohort of patients with suspect and early manifest primary open-angle glaucoma (POAG), a cohort of patients with perimetric POAG, and an external normative control cohort.

METHODS

A cardiovascular disease genetic risk score was calculated for 828 participants from the Progression Risk of Glaucoma: Relevant SNPs [single nucleotide polymorphisms] with Significant Association (PROGRESSA) study. Participants were characterized as showing either predominantly macular ganglion cell-inner plexiform layer (GCIPL), predominantly peripapillary retinal nerve fiber layer (pRNFL) or equivalent macular GCIPL and pRNFL spectral-domain OCT thinning. The cardiovascular disease genetic risk scores for these groups were compared to an internal reference group of stable suspected glaucoma and of an external normative population. Replication was undertaken by comparing the phenotypes of participants from the Australia New Zealand Registry of Advanced Glaucoma (ANZRAG) with the normative control group.

MAIN OUTCOME MEASURES

Spectral-domain OCT and Humphrey Visual Field (HVF) change.

RESULTS

After accounting for age, sex, and intraocular pressure (IOP), participants with predominantly macular GCIPL thinning showed a higher cardiovascular disease genetic risk score than reference participants (odds ratio [OR], 1.76/standard deviation [SD]; 95% confidence interval [CI], 1.18-2.62; P = 0.005) and than normative participants (OR, 1.32/SD; 95% CI, 1.12-1.54; P = 0.002). This finding was replicated by comparing ANZRAG participants with predominantly macular GCIPL change with the normative population (OR, 1.39/SD; 95% CI, 1.05-1.83; P = 0.022). Review of HVF data identified that participants with paracentral visual field defects also demonstrated a higher cardiovascular disease genetic risk score than reference participants (OR, 1.85/SD; 95% CI, 1.16-2.97; P = 0.010). Participants with predominantly macular GCIPL thinning exhibited a higher vertical cup-to-disc ratio genetic risk score (OR, 1.48/SD; 95% CI, 1.24-1.76; P < 0.001), but an IOP genetic risk score (OR, 1.12/SD; 95% CI, 0.95-1.33; P = 0.179) comparable with that of the normative population.

CONCLUSIONS

This study highlighted the relationship between cardiovascular disease and retinal thinning in suspect and manifest glaucoma cases.

Comparison of spectral domain optical coherence tomography parameters between disc suspects and "pre-perimetric" glaucomatous discs classified on disc photo

Purpose:

The aim of this study was to compare SD-OCT parameters between disc suspects and “pre-perimetric” glaucomatous discs classified on disc photos.

Methods:

Disc photos of suspicious discs with normal Humphrey visual fields (HVF) were graded as normal or pre-perimetric glaucomatous based on the consensus of three masked glaucoma specialists. RNFL and GCL-IPL maps of SD-OCT (Cirrus OCT) of these eyes were studied. Quantitative RNFL parameters were compared. Both groups were also compared with respect to parameters being classified as abnormal (at the 1% level), and the pattern of GCL-IPL and NFL maps were assessed qualitatively and classified as normal or pre-perimetric glaucomatous by a masked glaucoma specialist.

Results:

The average and inferior RNFL thicknesses were decreased in pre-perimetric glaucomatous eyes compared to normal eyes (p 0.01) The average, minimal, inferotemporal and inferior sector GCL-IPL thicknesses were decreased in pre-perimetric glaucomatous eyes (all P < 0.002) The highest AUC was for the inferior RNFL thickness (0.771) followed by average RNFL thickness (0.757) The sensitivity and specificity for any one abnormal RNFL parameter was 71.9% and 59.7%, for GCL-IPL parameters was 70% and 69.1% The positive (PLR) and negative likelihood ratios (NLR) were 1.78 and 0.47 for RNFL and 2.26 and 0.43 for GCL-IPL parameters. For the qualitative assessment of RNFL and GCL-IPL maps, the sensitivity, specificity, PLR and NLR were 75%, 77.2%, 3.29, and 0.32, respectively.

Conclusion:

Pre-perimetric disc suspects had greater OCT changes compared to normal disc suspects. Qualitative assessment of RNFL and GCL-IPL maps had the highest discriminatory ability.

Comparison of Changes in Macular Ganglion Cell-Inner Plexiform Layer Thickness Between Medically and Surgically Treated Eyes With Advanced Glaucoma

PURPOSE

To compare changes in the macular ganglion cell layer and inner plexiform layer (mGCIPL) thickness over 5 years between surgically treated eyes (STE) and medically treated eyes (MTE) with advanced glaucoma.

DESIGN

Retrospective, comparative case series.

METHODS

Eighty-six patients comprising 43 with open-angle glaucoma (OAG) with trabeculectomy and 43 with medically treated OAG. The mGCIPL thickness was measured more than 5 times during follow-up by optical coherence tomography. Main outcome measure was differences in mGCIPL thickness thinning rate between the groups.

RESULTS

The mean age at study initiation was 62.5 ± 9.2 years in STE and 62.7 ± 9.5 years in MTE. The mean deviations (MD), according to the Humphrey Field Analyzer central program 30-2, and the mGCIPL thickness in each sector showed no significant differences at initial measurement. The averaged intraocular pressure (IOP) throughout follow-up was 10.5 ± 2.0 mm Hg in STE and 10.8 ± 0.8 mm Hg in MTE (P = .429; Mann-Whitney U test). There was no significant difference in the MD changes over 5 years between the 2 groups (P = .405; Mann-Whitney U test). Changes in the mGCIPL thickness over 5 years in MTE were significantly greater than that in STE in all sectors (all 6 sectors P < .0001, Mann-Whitney U test). The IOP fluctuation over 5 years in STE was significantly less than that in MTE (P < .0001, Mann-Whitney U test).

CONCLUSIONS

The structure of the mGCIPL was better preserved in STE than in MTE, even when the IOPs during follow-up were similar.

Optical coherence tomography for glaucoma diagnosis: An evidence based meta-analysis

Purpose

Early detection, monitoring and understanding of changes in the retina are central to the diagnosis of glaucomatous optic neuropathy, and vital to reduce visual loss from this progressive condition. The main objective of this investigation was to compare glaucoma diagnostic accuracy of commercially available optical coherence tomography (OCT) devices (Zeiss Stratus, Zeiss Cirrus, Heidelberg Spectralis and Optovue RTVue, and Topcon 3D-OCT).

Patients

16,104 glaucomatous and 11,543 normal eyes reported in 150 studies.

Methods

Between Jan. 2017 and Feb 2017, MEDLINE^®, EMBASE^®, CINAHL^®, Cochrane Library^®, Web of Science^®, and BIOSIS^® were searched for studies assessing glaucoma diagnostic accuracy of the aforementioned OCT devices. Meta-analysis was performed pooling area under the receiver operating characteristic curve (AUROC) estimates for all devices, stratified by OCT type (RNFL, macula), and area imaged.

Results

150 studies with 16,104 glaucomatous and 11,543 normal control eyes were included. Key findings: AUROC of glaucoma diagnosis for RNFL average for all glaucoma patients was 0.897 (0.887–0.906, n = 16,782 patient eyes), for macula ganglion cell complex (GCC) was 0.885 (0.869–0.901, n = 4841 eyes), for macula ganglion cell inner plexiform layer (GCIPL) was 0.858 (0.835–0.880, n = 4211 eyes), and for total macular thickness was 0.795 (0.754–0.834, n = 1063 eyes).

Conclusion

The classification capability was similar across all 5 OCT devices. More diagnostically favorable AUROCs were demonstrated in patients with increased glaucoma severity. Diagnostic accuracy of RNFL and segmented macular regions (GCIPL, GCC) scans were similar and higher than total macular thickness. This study provides a synthesis of contemporary evidence with features of robust inclusion criteria and large sample size. These findings may provide guidance to clinicians when navigating this rapidly evolving diagnostic area characterized by numerous options.

Retinal Nerve Fiber Layer Damage in Young Myopic Eyes With Optic Disc Torsion and Glaucomatous Hemifield Defect

PURPOSE

To investigate retinal nerve fiber layer (RNFL) status at the opposite hemiretinas of optic disc torsion (ODT) in young myopic subjects with glaucomatous visual field (VF) defects and correlation between its thickness and VF defects using spectral-domain optical coherence tomography (SD-OCT).

PATIENTS AND METHODS

We assessed the frequency and characteristics of glaucomatous RNFL defects at the opposite hemiretinas of ODT location (ODT-unaffected hemiretinas) in 59 young myopic subjects presenting with glaucomatous VF defects confined to 1 hemifield, and compared the peripapillary RNFL thickness (pRNFLT) in ODT-unaffected hemiretinas of study eyes with that of 60 myopic controls without ODT using Cirrus HD SD-OCT. Linear regression analyses were performed between the pRNFLT measurements at ODT-unaffected hemiretinas and Humphrey field analyzer VF indices.

RESULTS

Approximately 42% of study eyes with ODT showed glaucomatous RNFL defects at ODT-unaffected hemiretinas. The mean width of RNFL defects was significantly greater in ODT-affected hemiretinas than in ODT-unaffected hemiretinas (P<0.001). The mean pRNFLT in ODT-unaffected hemiretinas of study group (99.9±12.1 μm) was significantly lower than that in the matched hemiretinas of control group (109.8±14.9 μm; P<0.001). Significant correlations were observed between pRNFLT parameters and Humphrey field analyzer indices for each hemiretina with or without ODT in the study group.

CONCLUSIONS

Young myopic eyes with ODT and hemifield VF loss often show glaucomatous RNFL defects at both hemiretinas and significantly lower pRNFLT in the ODT-unaffected hemiretinas compared with matched hemiretinas of control eyes. Greater VF loss is associated with more advanced pRNFT loss in ODT-unaffected hemiretinas.

Optic nerve head and fibre layer imaging for diagnosing glaucoma

BACKGROUND

The diagnosis of glaucoma is traditionally based on the finding of optic nerve head (ONH) damage assessed subjectively by ophthalmoscopy or photography or by corresponding damage to the visual field assessed by automated perimetry, or both. Diagnostic assessments are usually required when ophthalmologists or primary eye care professionals find elevated intraocular pressure (IOP) or a suspect appearance of the ONH. Imaging tests such as confocal scanning laser ophthalmoscopy (HRT), optical coherence tomography (OCT) and scanning laser polarimetry (SLP, as used by the GDx instrument), provide an objective measure of the structural changes of retinal nerve fibre layer (RNFL) thickness and ONH parameters occurring in glaucoma.

OBJECTIVES

To determine the diagnostic accuracy of HRT, OCT and GDx for diagnosing manifest glaucoma by detecting ONH and RNFL damage.

SEARCH METHODS

We searched several databases for this review. The most recent searches were on 19 February 2015.

SELECTION CRITERIA

We included prospective and retrospective cohort studies and case-control studies that evaluated the accuracy of OCT, HRT or the GDx for diagnosing glaucoma. We excluded population-based screening studies, since we planned to consider studies on self-referred people or participants in whom a risk factor for glaucoma had already been identified in primary care, such as elevated IOP or a family history of glaucoma. We only considered recent commercial versions of the tests: spectral domain OCT, HRT III and GDx VCC or ECC.

DATA COLLECTION AND ANALYSIS

We adopted standard Cochrane methods. We fitted a hierarchical summary ROC (HSROC) model using the METADAS macro in SAS software. After studies were selected, we decided to use 2 x 2 data at 0.95 specificity or closer in meta-analyses, since this was the most commonly-reported level.

MAIN RESULTS

We included 106 studies in this review, which analysed 16,260 eyes (8353 cases, 7907 controls) in total. Forty studies (5574 participants) assessed GDx, 18 studies (3550 participants) HRT, and 63 (9390 participants) OCT, with 12 of these studies comparing two or three tests. Regarding study quality, a case-control design in 103 studies raised concerns as it can overestimate accuracy and reduce the applicability of the results to daily practice. Twenty-four studies were sponsored by the manufacturer, and in 15 the potential conflict of interest was unclear.Comparisons made within each test were more reliable than those between tests, as they were mostly based on direct comparisons within each study.The Nerve Fibre Indicator yielded the highest accuracy (estimate, 95% confidence interval (CI)) among GDx parameters (sensitivity: 0.67, 0.55 to 0.77; specificity: 0.94, 0.92 to 0.95). For HRT measures, the Vertical Cup/Disc (C/D) ratio (sensitivity: 0.72, 0.60 to 0.68; specificity: 0.94, 0.92 to 0.95) was no different from other parameters. With OCT, the accuracy of average RNFL retinal thickness was similar to the inferior sector (0.72, 0.65 to 0.77; specificity: 0.93, 0.92 to 0.95) and, in different studies, to the vertical C/D ratio.Comparing the parameters with the highest diagnostic odds ratio (DOR) for each device in a single HSROC model, the performance of GDx, HRT and OCT was remarkably similar. At a sensitivity of 0.70 and a high specificity close to 0.95 as in most of these studies, in 1000 people referred by primary eye care, of whom 200 have manifest glaucoma, such as in those who have already undergone some functional or anatomic testing by optometrists, the best measures of GDx, HRT and OCT would miss about 60 cases out of the 200 patients with glaucoma, and would incorrectly refer 50 out of 800 patients without glaucoma. If prevalence were 5%, e.g. such as in people referred only because of family history of glaucoma, the corresponding figures would be 15 patients missed out of 50 with manifest glaucoma, avoiding referral of about 890 out of 950 non-glaucomatous people.Heterogeneity investigations found that sensitivity estimate was higher for studies with more severe glaucoma, expressed as worse average mean deviation (MD): 0.79 (0.74 to 0.83) for MD < -6 db versus 0.64 (0.60 to 0.69) for MD ≥ -6 db, at a similar summary specificity (0.93, 95% CI 0.92 to 0.94 and, respectively, 0.94; 95% CI 0.93 to 0.95; P < 0.0001 for the difference in relative DOR).

AUTHORS' CONCLUSIONS

The accuracy of imaging tests for detecting manifest glaucoma was variable across studies, but overall similar for different devices. Accuracy may have been overestimated due to the case-control design, which is a serious limitation of the current evidence base.We recommend that further diagnostic accuracy studies are carried out on patients selected consecutively at a defined step of the clinical pathway, providing a description of risk factors leading to referral and bearing in mind the consequences of false positives and false negatives in the setting in which the diagnostic question is made. Future research should report accuracy for each threshold of these continuous measures, or publish raw data.

Evaluating glaucoma damage: emerging imaging technologies

The use of ocular imaging tools to estimate structural and functional damage in glaucoma has become a common clinical practice and a substantial focus of vision research. The evolution of the imaging technologies through increased scanning speed, penetration depth, image registration and development of multimodal devices has the potential to detect the pathology more reliably and in earlier stages. This review is focused on new ocular imaging modalities used for glaucoma diagnosis.

The glaucoma detection capability of spectral-domain OCT and GDx-VCC deviation maps in early glaucoma patients with localized visual field defects

PURPOSE

To evaluate and compare the glaucoma detection capabilities afforded by retinal nerve fiber layer (RNFL) thickness and deviation maps obtained using Cirrus spectral domain optical coherence tomography (Cirrus OCT), and GDx employing variable corneal compensation (GDx-VCC) in glaucoma patients with early, localized visual field (VF) loss.

METHODS

This prospective controlled, comparative study was performed on 42 eyes with localized VF defects, and 42 age/refractive error-matched healthy eyes. All participants were imaged by both imaging devices at the same visit. The area of the RNFL defect in each deviation map, corresponding to a VF defect, was analyzed by direct counting of color-coded superpixels in each device. Receiver operating characteristic (ROC) curves were constructed and compared between Cirrus OCT and GDx-VCC.

RESULTS

The areas under the ROCs (AUCs) of RNFL quadrant thicknesses in hemifields with visual field (VF) defects did not differ significantly (Cirrus OCT; 0.961, GDx-VCC; 0.919, P = 0.07). However, Cirrus OCT afforded a better diagnostic ability, by deviation map analysis, than did GDx-VCC (0.972 vs 0.887, P = 0.02).

CONCLUSIONS

The RNFL thicknesses assessed by either Cirrus OCT or GDx-VCC were comparable in terms of early glaucoma diagnostic capability. However, when areas containing RNFL defects were analyzed via deviation mapping, Cirrus OCT was better than GDx-VCC.

Diagnostic ability of retinal nerve fiber layer maps to detect localized retinal nerve fiber layer defects

PURPOSE

To evaluate and compare the diagnostic ability of spectral domain optical coherence tomography (SD-OCT) for detecting localized retinal nerve fiber layer (RNFL) defects in topographic RNFL maps and circumpapillary RNFL (cpRNFL) thickness measurements.

METHODS

Sixty-four eyes with localized RNFL defects in red-free RNFL photographs and 72 healthy eyes were included. All participants were imaged with SD-OCT. The area and angular width of the localized RNFL defects were measured with ImageJ software on RNFL thickness map, significance map (yellow pixels, <5% level), and red-free RNFL photographs. The sensitivity, specificity, and area under the receiver operating characteristic curves (AUCs) were calculated for cpRNFL thickness, macular inner retina thickness, and RNFL maps (thickness, significance) according to the quantitative measurements and a <5% level of classification to distinguish eyes with localized RNFL defects from healthy eyes.

RESULTS

RNFL thickness map (sensitivity 96.9-98.4%, specificity 86.1-98.6%, and AUCs 0.915-0.992) and significance map (sensitivity 96.9-98.4%, specificity 88.9-95.8%, and AUCs 0.937-0.983) showed superior performance in detecting localized RNFL defects compared with other parameters (P-value 0.001-0.024) except for 36 sector cpRNFL thickness (sensitivity 92.2%, specificity 87.5%, and AUCs 0.898; P-value 0.080-0.545). The sensitivity for detecting RNFL defects was related to the angular width, area, and depth of the RNFL defects in the cpRNFL (4 sector, 12 sector) and macular inner retinal measurements. RNFL thickness and significance maps showed a constant sensitivity regardless of variations in angular width, area, and depth of the RNFL defects.

CONCLUSION

RNFL thickness and significance maps could be used to distinguish eyes with localized RNFL defects from healthy eyes more effectively than cpRNFL thickness and macular inner retina thickness measurements.