Reproducibility of disc and macula optical coherence tomography using the Canon OCT-HS100 as compared with the Zeiss Cirrus HD-OCT

Influence of signal‐to‐noise ratio, glaucoma stage and segmentation algorithm on OCT usability for quantifying layer thicknesses in the peripapillary retina

PURPOSE

OCT can be used for glaucoma assessment, but its usefulness may depend on image quality, disease stage and segmentation algorithm. We aimed to determine how layer thicknesses as assessed with different algorithms depend on image quality and disease stage, how reproducible the algorithms are, and if the algorithms (dis)agree.

METHODS

Optic disc OCT data (Canon OCT-HS100) from 20 healthy subjects and 28 early, 29 moderate, and 23 severe glaucoma patients were assessed with four different algorithms (CANON, IOWA, FWHM, DOCTRAP). We measured retinal nerve fibre layer thickness (RNFLT) and total retinal thickness (TRT) along the 1.7-mm-radius OCT measurement circle centred at the optic disc. In healthy subjects, image quality was degraded with neutral density filters (0.3-0.9 optical density [OD]); three scans were made to assess repeatability. Results were analysed with ANOVA with Bonferroni corrected t-tests for post hoc analysis and with intraclass correlation coefficient (ICC) analysis.

RESULTS

For all algorithms, RNFLT was more sensitive to image quality than TRT. Both RNFLT and TRT showed differences between healthy and glaucoma (all algorithms p < 0.001 for both RNFLT and TRT) and between early and moderate glaucoma (RNFLT: p = 0.001 to p = 0.09; TRT: p < 0.001 to p = 0.03); neither was able to discriminate between moderate and severe glaucoma (p = 0.08 to p = 1.0). Generally, repeatability was excellent (ICC >0.75); agreement between algorithms varied from moderate to excellent.

CONCLUSIONS

OCT becomes less informative with glaucoma progression, irrespective of the algorithm. For good-quality scans, RNFLT and TRT perform similarly; TRT may be advantageous with poor image quality.

Comparison of the Thickness of the Fiber Layer of the Retinal Nerves in Spectral Domain Optical Coherence Tomography in Normal Eyes Older Than 40 Years

PURPOSE

To compare measurements of the thickness of the retinal nerve fibre layer (RNFL) and assess the agreement between three different devices for spectral domain optical coherence tomography.

MATERIAL AND METHODS

The RNFL thickness of both eyes of 23 normal subjects older than 40 years was measured using Canon HS100, Topcon Maestro, and NIDEK RS-3000 devices. Both eyes of each subject were scanned in random order. All scans were completed on the same day in the morning. The average and four quadrants (superior, inferior, nasal, and temporal) of RNFL thickness were measured. To determine the differences in RNFL thickness, analysis of variance for repeated measurements was performed. A Bland-Altman plot was plotted, and coefficients of determination were calculated.

RESULTS

A total of 46 eyes of 23 subjects were enrolled in this study. The average RNFL thickness as determined by the three OCT devices was correlated (p < 0.001), but differed significantly between the three devices, as most were quadrant measurements. The mean average RNFL thickness was 98.5 ± 6.6 µm as measured by Canon HS100, 108.5 ± 8.8 µm as measured by Topcon Maestro, and 104.9 ± 9.0 µm as measured by NIDEK RS-3000. Topcon Maestro showed the highest average RNFL thickness value. Bland-Altman plots revealed considerable agreement among the three devices, except for the inferior quadrants between Topcon Maestro and NIDEK RS-3000 measurements. All three devices reveal considerable coefficients of determination values for mean RNFL thickness (0.917 - 0.127).

CONCLUSION

Although the peripapillary RNFL thickness measurements taken with Canon HS100, Topcon Maestro, and NIDEK RS-3000 were in good agreement, they were not interchangeable in clinical practice, as the values differed significantly.

Topographic distribution features of the choroidal and retinal nerve fiber layer thickness in Chinese school-aged children

AIM

To explore the topographic distribution features of choroidal thickness (CT) and retinal nerve fiber layer thickness (RNFLT), and determine the relationship between CT and ocular parameters in school-aged children.

METHODS

The healthy school-aged children with low ametropia or emmetropia in Wenzhou were recruited for this cross-sectional study. With high-density optical coherence tomography (HD-OCT) combined with MATLAB software, the CT and RNFLT values in the macular area were measured at different locations and compared. Statistical analyses were performed to evaluate the correlation between CT and ophthalmic parameters, such as spherical equivalent (SE) and the axial length (AL).

RESULTS

A total of 279 school-aged children with 8.00±1.35 years of mean age (range, 6-10y) were included. The mean AL was 23.66±0.86 mm. The mean CT in CT-C (264.31±48.93 µm) was thicker than that in CT-N1 (249.54±50.52 µm), and the average CT in the parafoveal region was also thicker than that in CT-N2 (235.65±50.63 µm). The subfoveal CT also varied substantially across refractive errors (P<0.001), and those with myopia (250.59±47.01 µm) exhibited a thinner choroid compared with those with emmetropia (278.74±48.06 µm). CT negatively correlated with AL (y=-21.72x+779.17; R ²=0.1458), and positively correlated with SE (y=15.76x+271.9; R ²=0.0727, OD; y=18.31x+269.8; R ²=0.1007, OS). The average RNFLT was thickest in the peripapillary region (236.35±19.03 µm), the mean RNFLT-S (131.10±15.16 µm) was thicker than the RNFLT-I (128.20±16.59 µm), and the mean RNFLT-T (76.54±11.99 µm) was thicker than the RNFLT-N (64.28±8.55 µm). The variations in the RNFLT between quadrants did differ between those with myopia and emmetropia (P<0.05).

CONCLUSION

We establish demographic information for the choroid and RNFLT. These findings provide information that should be considered in future analyses of the CT and RNFLT in OCT studies in school-aged children.

Risk Factors for Onset or Progression of Posterior Vitreous Detachment at the Vitreomacular Interface after Cataract Surgery

PURPOSE

To study the incidence and risk factors for onset or progression of posterior vitreous detachment (PVD) at the vitreomacular interface (VMI) after cataract surgery.

DESIGN

Retrospective case series.

PARTICIPANTS

Patients with a history of phacoemulsification from April 2018 through April 2019 at the Keye Eye Center, Seoul, Korea, and postoperative monitoring for more than 2 months.

METHODS

Cox proportional hazard ratios for the onset or development of PVD after cataract surgery in the presence of selected risk factors and demographic data were calculated. To evaluate the ocular risk factors, various ocular metrics, including spherical equivalent (SE), axial length (AL), anterior chamber depth, lens thickness, central subfield thickness, PVD status at macula and optic nerve head (ONH), peripapillary retinal nerve fiber layer thickness, and ONH parameters from OCT scans, were used for the analysis.

MAIN OUTCOME MEASURES

Onset or development of PVD at the VMI.

RESULTS

Among 988 eyes without PVD at baseline, 174 eyes (17.6%) showed changes in the VMI. Univariate analysis showed that age, SE, AL, PVD status at macula and ONH, and average and vertical cup-to-disc ratios (CDRs) were associated significantly with PVD onset or development (P = 0.046, P = 0.004, P = 0.040, P < 0.001, P < 0.001, P = 0.008, and P = 0.042, respectively). In a multivariate analysis, PVD status at the macula and ONH and smaller CDR were associated with PVD onset or progression after cataract surgery after adjustment for age, SE, and AL (P < 0.001, P < 0.001, and P = 0.005, respectively).

CONCLUSIONS

The risk of PVD onset or progression was dependent on PVD status and the CDR detected on OCT scans, not on age or AL, in a large patient cohort. Patients who show risk factors on OCT should be monitored carefully during the postoperative period.

Retinal nerve fiber layer thickness associates with cognitive impairment and physical disability in multiple sclerosis

BACKGROUND

Reductions of the peripapillary retinal nerve fiber layer (pRNFL) thickness has been indicated even in early-stages of multiple sclerosis (MS). The aim was to investigate the association between pRNFL thickness, measured with optical coherence tomography (OCT), and physical disability and cognitive impairment in MS.

METHODS

465 MS patients and 168 healthy controls (HCs) were included. MS subjects were divided into subgroups according to disease subtype. All subjects underwent OCT examination of all pRNFL quadrants using Canon OCT-HS100. Associations were tested using linear mixed effect models. Physical disability was assessed with the Expanded Disability Status Scale (EDSS) and cognitive function with the Symbol Digit Modalities Test (SDMT).

RESULTS

The average pRNFL, inferior pRNFL and temporal pRNFL thicknesses were significantly correlated to both EDSS (-1.0 µm, p < 0.01; -1.2 µm, p < 0.05; -1.2 µm, p < 0.01) and SDMT (0.1 µm, p < 0.05; 0.2 µm, p < 0.05; 0.2 µm, p < 0.01). A significant thickness loss compared with HCs was seen in the average pRNFL and in all quadrants except for the superior quadrant of primary progressive MS. The largest reduction compared with HCs was seen in the temporal pRNFL of PPMS eyes (-15.8 µm; p < 0.001).

CONCLUSION

The reduction of average pRNFL, inferior pRNFL and temporal pRNFL thickness is associated with physical and cognitive disability in MS. We suggest the use of temporal pRNFL as a more sensitive outcome as it showed the strongest association to both EDSS and SDMT.

The Temporal Retinal Nerve Fiber Layer Thickness Is the Most Important Optical Coherence Tomography Estimate in Multiple Sclerosis

BACKGROUND

Reduced peripapillary retinal nerve fiber layer (pRNFL) and combined ganglion cell and inner plexiform layer (GCIP) thicknesses as measured by optical coherence tomography (OCT) have been observed in multiple sclerosis (MS) patients. The purpose was to determine the most associative OCT measure to level of cognitive and physical disability in MS.

METHODS

Data were collected from 546 MS patients and 175 healthy controls (HCs). We compared the average pRNFL, temporal pRNFL (T-pRNFL), overall inner ganglion cell/inner plexiform layer (GCIP), and the overall ganglion cell complex (GCC) including macular RNFL and GCIP thicknesses measurements in differentiating MS subtypes from HCs. The association between OCT measures, Expanded Disability Status Scale (EDSS), and Symbol Digit Modalities Test (SDMT) were assessed using generalized estimating equations models.

RESULTS

Both peripapillary and macular OCT measurements could differentiate all MS subtypes from HCs. The SDMT score was significantly associated with reduced thickness of all OCT measures, mostly in average pRNFL (0.14 µm, P = 0.001) and T-pRNFL (0.17 µm, P < 0.001). The EDSS score was significantly associated with reduced inner retinal layer thickness. The largest reduction was seen in T-pRNFL (-1.52 μm, P < 0.001) and inner GCC (-1.78 μm, P < 0.001).

CONCLUSION

The T-pRNFL is highly sensitive and associated with level of both cognitive and physical disability.

Microarchitecture of the Vitreous Body: A High-Resolution Optical Coherence Tomography Study

PURPOSE

To report novel vitreous body microarchitecture findings using high-resolution spectral-domain optical coherence tomography (HR-SD-OCT).

DESIGN

Prospective, cross-sectional study.

METHODS

Horizontal and vertical retinal cross-sectional images that were 10 mm long were acquired from 17 eyes of 17 young healthy volunteers using HR-SD-OCT with enhanced vitreous imaging (EVI). Images were acquired through the fovea, upper vessel arcade, and lower vessel arcade.

RESULTS

Three new findings on vitreous body microarchitecture were found. First, material located between the retina and posterior vitreous cortex was easily detected in 90% of upper and lower vessel arcade scans. Most scans contained hyperreflective dots and multilayered hyperreflective lines around the detached vitreous cortex. Second, a lamellar structure was observed in the vitreous body in 70%-80% of all scans, excluding vertical scans of the upper arcade vessel area. Third, tubular zones of hypodensity were detected in >80% of scans, excluding horizontal scans of the macula. Interestingly, the location of tubular zones of hypodensity seemed to correspond with the location of retinal vessels. Subject age, refractive error, and axial length were not significantly different in scans with and without material between the retina and vitreous, lamellar structures, and tubular zones of hypodensity.

CONCLUSIONS

The microarchitecture of the vitreous body can be visualized using HR-SD-OCT and EVI.

Repeatability Using Automatic Tracing with Canon OCT- HS100 and Zeiss Cirrus HD-OCT 5000

Background

Optical coherence tomography (OCT), can be used in clinical practice to provide high resolution cross-sectional images of the retina, optic disc and macula structure. These measurements can be useful for early detection, diagnosis, monitoring and treatment guidance for retinal diseases. Therefore, repeatability of measurements in OCT is of great importance.

Methods

Macula and optic disc parameters from the right eye of 30 healthy subjects were obtained twice with the Canon OCT-HS100 and Zeiss Cirrus HD-OCT 5000. Repeatability was evaluated by use of the coefficient of repeatability (CR) and the coefficient of repeatability as a percentage of the mean (CR%), and the obtained measurements were compared between the instruments.

Results

CR% of optic disc parameters ranged between 0.90 and 22.22% and 0.00 and 16.00% with the Canon and Zeiss OCT respectively. For macular parameters CR% ranged between 0.62 and 2.81% and 0.99 and 1.81% with the Canon and Zeiss OCT respectively. No statistical difference could be found when comparing the CR of all macular and disc measurements between the instruments. Compared to our previously published data repeatability has significantly improved with the inclusion of automatic tracking systems with both the Canon and Zeiss OCT.

Conclusion

Automatic tracking function improves repeatability in both Canon OCT-HS100 and Zeiss Cirrus HD-OCT 5000. However, measurements generated by the two instruments are still not interchangeable.

[Evaluation of the new Canon HS-100 SD-OCT: Reproducibility of macular ganglion cell complex (GCC) thickness measurement in normal, hypertensive and glaucomatous eyes]

PURPOSE

To evaluate intra- and interobserver reproducibility of macular GCC thickness measurement by automated segmentation on the Canon HS-100 SD-OCT (Tokyo, Japan) in normal (N), hypertensive (OHT) and glaucomatous eyes.

METHODS

A total of 179 eyes of 93 patients were included: 90 N, 28 OHT and 36 early glaucoma and 25 advanced glaucoma. All patients underwent a complete ophthalmologic exam, central corneal thickness and 24-2 standard automated perimetry (HFA SITA standard). Each of two observers performed three macular acquisitions with the Canon OCT HS-100. Acquisitions were analyzed with the Glaucoma 3D mode, which estimated the macular GCC thickness in global, superior and inferior hemisectors, and in eight separate macular areas. Reproducibility was assessed by intraclass correlation coefficient (ICC), coefficient of variation (CV) and test-retest variability (TRTV) calculated as 1.96 times the standard deviation.

RESULTS

Mean GCC thickness was respectively 92.4 μm, 89.0 μm, 80.7 μm and 71.2 μm in N, OHT, early and advanced glaucomatous eyes. In all groups, intra- and interobserver reproducibility ranged respectively for ICC from 89.8 to 99.8% and from 90.2 to 99.4%, for CV from 0.43 to 1.95% and from 0.58 to 2.16% and for TRTV from 0.8 to 3.22 μm and from 1.04 to 3.53 μm. GCC thickness measurements using the new HS-100 SD-OCT were highly reproducible. However, in the advanced glaucoma group, while the reproducibility of GCC thickness measurement is good in the average, superior and inferior hemisectors of the macula, it was slightly less for the paracentral sectors, especially inferior. These sectors correspond generally to the areas most affected by glaucoma.

CONCLUSION

The reproducibility of GCC thickness measurements using the new Canon HS-100 SD-OCT is high for normal, OHT, and glaucomatous eyes. It is thus a reliable and reproducible ancillary test available to the clinician for the examination of glaucomatous optic neuropathies.