Ganglion cell layer segmentation and the two-flash multifocal electroretinogram improve structure function analysis in early glaucoma

Objective To evaluate the repeatability and reproducibility of macular ganglion cell-inner plexiform layer (GCIPL) thickness measurement using spectral-domain optical coherence tomography (Cirrus HD-OCT).Method One hundred and eight eyes of 54 normal subjects (26 males and 28 females) between 19 and 75 years of age [mean age (46.2± 16.5) years] were included.Each eye underwent macular scanning using Cirrus HD-OCT Macular Cube 512 × 128 protocol by two operators.Three scans of each eye were obtained by each operator.For the right eye of each subject,three extra scans were obtained using Macular Cube 200 × 200 protocol by one operator.The average,minimum,superotemporal,superior,superonasal,inferonasal,inferior,and inferotemporal GCIPL thickness was analyzed and the repeatability of GCIPL thickness measurement was evaluated with intra-operator,inter-operator,intra-protocol,and inter-protocol intraclass correlation coefficients (ICC).Ten extra scans were obtained from the left eyes of 10 randomly selected subjects for reproducibility assessment with coefficients of variation (CV).Results The intra-operator ICC of macular GCIPL measurement using Macular Cube 512 × 128 protocol by two operators were 0.959-0.995 and 0.954-0.997,respectively; and the inter-operator ICC were 0.944-0.993.All intra-and inter operator ICC were ＞0.800 with the highest and lowest records of the average and minimum GCIPL thickness,respectively.The intra-protocol ICC of Macular Cube 512 × 128 protocol and Macular Cube 200× 200 protocol were 0.986-0.996 and 0.927-0.997,respectively; and the inter-protocol ICC were 0.966 0.994.All intra-and inter-protocol ICC were ＞0.800.CV of GCIPL thickness measurement using MacularCube 512×128 protocol were (0.70±0.31)％ (1.35±0.86)％.Conclusion Cirrus HDOCT can measure macular GCIPL thickness in normal eyes with excellent repeatability and reproducibility. Key words: Macula lutea/anatomy & histology; Retinal ganglion cells; Tomography, optical coherence; Reproducibility of results

The standard automated perimetry (SAP) 24-2 test cannot adequately test the paracentral region because test points are located sparsely in macular area where is crowded with retinal ganglion cells (RGCs), even though paracentral scotoma is clinically related to a risk of losing visual function. More sensitive visual field (VF) tests are needed to assess paracentral VF defects precisely. We investigated the structure–function relationship on the SAP 10-2 test and the frequency doubling technology (FDT) 24-2 test as well as the SAP 24-2 test in glaucoma with parafoveal scotoma (PFS). Glaucoma patients with PFS (134 patients) were included in this cross-sectional study. Sub-analysis was performed with isolated PFS (51 patients). Global and sectoral mean sensitivities (MS) were evaluated using SAP 24-2, 10-2, and FDT 24-2 program. MS was analyzed as dB or unlogged 1/lambert (SAP) or 1/Michelson contrast (FDT). Ganglion cell-inner plexiform layer (GCIPL) thickness was measured using spectral domain optical coherence tomography. Topographic relationships between the structure and the function were analyzed. In the total PFS group, good structure–function correlations were found in all zones with SAP 24-2, 10-2, and FDT 24-2 test. For glaucoma with isolated PFS, average GCIPL thickness was significantly correlated with central cluster MS (dB) using the SAP 10-2 test (r = 0.279, P = .047) and the FDT 24-2 test (r = 0.289, P = .039), but not the SAP 24-2 test (r = 0.264, P = .061). Topographically, the FDT 24-2 test showed significant correlations in all sectors between sectoral MS and corresponding GCIPL thickness. With regard to the SAP 10-2 test, there was significant topographical structure–function correlations for the superotemporal, inferotemporal, and inferonasal sectors. For SAP 24-2, only inferonasal GCIPL thickness was correlated with the corresponding VF sensitivity. Topographical structure–function on the macula was better with the SAP 10-2 test (superotemporal sector) and the FDT 24-2 test (superotemporal sector) than with the SAP 24-2 test in glaucoma with isolated PFS. In conclusion, FDT 24-2 and SAP 10-2 tests performed more favorably than the SAP 24-2 test in the structure–function relationship of glaucoma patients with isolated paracentral scotoma. FDT 24-2 tests can be another good option for detecting and monitoring RGC loss on the macular area while not missing VF defects outside the central 10°.

Profiles of Ganglion Cell-Inner Plexiform Layer Thickness in a Multi-Ethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study

To determine the distribution, variation, and determinants of ganglion cell-inner plexiform layer (GC-IPL) thickness in nonglaucomatous eyes measured by high-definition optical coherence tomography (HD-OCT). Six hundred twenty-three Chinese adults aged 40 to 80 years were consecutively recruited from a population-based study. All subjects underwent a standardized interview, ophthalmic examination, and automated perimetry. HD-OCT with macular cube protocol was used to measure the GC-IPL thickness. Univariate and multiple linear regression analyses were performed to examine the relationship between GC-IPL thickness with ocular and systemic factors. The mean (±SD) age of study subjects was 52.84 ± 6.14 years, 50.1% were male, and all subjects had normal visual fields with no signs of glaucoma or glaucoma suspect. The mean overall, minimum, superior, and inferior GC-IPL thicknesses were 82.78 ± 7.01 μm, 79.67 ± 9.17 μm, 83.30 ± 7.89 μm, and 80.16 ± 8.31 μm, respectively. In multiple linear regression analysis, GC-IPL thickness was significantly associated with age (β = -0.202, P < 0.001), female sex (β = -2.367, P < 0.001), axial length (β = -1.279, P = 0.002), and mean peripapillary retinal nerve fiber layer (RNFL) thickness (β = 0.337, P < 0.001). IOP, central corneal thickness, disc area, serum glucose level, and history of diabetes mellitus had no significant influence on GC-IPL thickness. Thinner GC-IPL was independently associated with older age, female sex, longer axial length, and thinner RNFL thickness. These factors should be taken into account when interpreting GC-IPL thickness measurements with HD-OCT for glaucoma assessment.

BackgroundThe purpose was to study the macular ganglion cell- inner plexiform layer (GC-IPL) thickness in healthy 6.5 year- old Swedish children using Optical Coherence Tomography (OCT) and to study topography symmetry within eyes and between eye pairs.MethodsA total of 181 eyes of 92 healthy children (39 girls, 53 boys) aged 6.5 and serving as a term-born control group in the Extremely Preterm Infants in Sweden Study (EXPRESS), were examined with Cirrus HD-OCT. Main outcome measures were average and minimum values of GC-IPL thickness of the device’s predefined macular sectors. Single sectors, combined sectors defined as superior and inferior hemispheres and temporal and nasal sectors were evaluated. Intra-individual GC-IPL thickness between eye pairs was analyzed. Visual acuity, refraction and general cognition were assessed and correlated to GC-IPL outcome.ResultsEighty-five children completed the OCT examination and 155 out of 181 scans (86%) were analyzed. The mean average GC-IPL thickness was 85.9 μm (± 5.3; 5th and 95th percentiles were 76.0 and 94.6 μm). The mean minimum GC-IPL thickness was 83.6 μm (± 4.9; 5th and 95th percentiles were 75.4 and 92.3 μm). The difference in thickness between nasal and temporal sectors and between superior and inferior hemisphere sectors were less than 2 μm. The difference between average GC-IPL thickness and minimum GC-IPL thickness was 2.3 μm (± 1.9; 5th and 95th percentiles were 0.0 and 6.0 μm). The difference between the thickest and thinnest sector within eye was 6.4 μm (± 2.2; 5th and 95th percentiles were 3.0 and 10.0 μm). There was a moderate correlation in the difference between the nasal combined and the temporal combined sectors within eye pairs (p < 0.0001, Spearman’s ρ 0.58). The average GC-IPL thickness was weakly positively correlated with SE (spherical equivalent; combined sphere and ½ cylinder) (p = 0.031, Spearman’s ρ 0.23).ConclusionsThis study provides normative GC-IPL thickness values for healthy 6.5 year- old Swedish children. The GC-IPL thickness variations within eyes and within eye pairs are generally small. It could therefore be assumed that larger variations are sensitive markers of focal GC-IPL thinning due to damage to the primary visual pathways in children.

BACKGROUND:The aim of this study was to evaluate responses on multifocal electroretinogram (mfERG) with ganglion cell-inner plexiform layer (GCIPL) thickness on cirrus spectral-domain optical coherence tomography (SD-OCT) in glaucoma.METHODS:All diagnosed glaucoma patients attending glaucoma services at our institute from November 2012 to April 2013 were screened for this observational hospital-based study. Controls included patients attending our outpatient services for general eye checkup. Structural parameters on SD-OCT including GCIPL and retinal nerve fiber layer (RNFL) thickness were compared with functional parameters on mfERG in early (mean deviation <−6 dB), moderate (−6 to − 12 dB), and controls.RESULTS:A total of 54 cases and 33 controls fulfilling inclusion criteria were recruited for the study. The average and minimum GCIPL thickness did not vary significantly between early and control eyes while moderate glaucoma eyes had marginally lower GCIPL thickness than early glaucoma eyes. The GCIPL minimum thickness on univariate regression was found to be influenced by N2 amplitudes (β = −0.5, P = 0.012) and global N2P1amplitudes (β =0.6, P = 0.01) in moderate glaucoma. In early glaucoma, these were influenced only by RNFL parameters with no association with functional mfERG responses. Multivariate logistic regression identified global N2P1 amplitude to be significantly influencing GCIPL average and minimum thickness (P = 0.01 and 0.02, R2 = 47.8% and 52.3%, respectively) in moderate glaucoma. Maximum area under the curve was found for GCIPL minimum (95% confidence interval [CI] 0.53–0.81) and N2P1 amplitude (95% CI 0.55–0.80).CONCLUSIONS:The second order responses N2P1 and N2 amplitude on mfERG predict function that correlated with structural GCIPL thickness in moderate glaucoma. Early glaucoma may be best predicted by RNFL thickness rather than on mfERG responses.

Ganglion Cell-Inner Plexiform Layer Thickness after Epiretinal Membrane Surgery: A Spectral-Domain Optical Coherence Tomography Study

To study the distribution of macular ganglion cell-inner plexiform layer (GC-IPL) thickness and peripapillary retinal nerve fiber layer (RNFL) thickness in children with refractive errors. Two hundred forty-three healthy eyes from 139 children with refractive error ranging from -10.00 to +5.00 D were recruited from the National University Hospital Eye Surgery outpatient clinic. After a comprehensive ocular examination, refraction, and axial length (AL) measurement (IOLMaster), macular GC-IPL and RNFL thickness values were obtained with a spectral domain Cirrus high definition optical coherence tomography system (Carl Zeiss Meditec Inc.). Only scans with signal strength of >6/10 were included. Correlation between variables was calculated using the Pearson correlation coefficient. A multivariate analysis using mixed models was done to adjust for confounders. The mean spherical equivalent refraction was -3.20±3.51 D and mean AL was 24.39±1.72 mm. Average, minimum, superior, and inferior GC-IPL were 82.59±6.29, 77.17±9.65, 83.68±6.96, and 81.64±6.70 μm, respectively. Average, superior, and inferior peripapillary RNFL were 99.00±11.45, 123.20±25.81, and 124.24±22.23 μm, respectively. Average, superior, and inferior GC-IPL were correlated with AL (β=-2.056, P-value 0.000; β=-2.383, P-value 0.000; β=-1.721, P-value 0.000), but minimum GC-IPL was not (β=-1.056, P-value 0.115). None of the RNFL parameters were correlated with AL. This study establishes normative macular GC-IPL and RNFL thickness in children with refractive errors. Our results suggest that high definition optical coherence tomography RNFL parameters and minimum GC-IPL are not affected by AL or myopia in children, and therefore warrants further evaluation in pediatric glaucoma patients.

PurposeTo evaluate the spatial relationship between macular superficial vessel density (SVD) and macular ganglion cell-inner plexiform layer (GCIPL) thickness in primary angle closure glaucoma (PACG), and to investigate diagnostic abilities of macular SVD and foveal avascular zone (FAZ) parameters.MethodsThis was a cross-sectional study on 38 PACG patients (38 eyes) and 25 healthy subjects (25 eyes). Macular region was imaged using a 1050-nm-wavelength swept-source optical coherence tomography (OCT) angiography (OCTA) system (DRI OCT Triton, TOPCON). Vessel density of the macular region was quantified by ImageJ software. The peripapillary retinal nerve fiber layer (pRNFL) thicknesses and macular GCIPL thickness were obtained by swept-source OCT. Pearson correlation analysis was used to evaluate the spatial positional relationship between macular SVD and macular GCIPL thickness. At the same time, the correlation between macular SVD and pRNFL thickness was evaluated. Areas under the receiver operating characteristics curves (AUCs) of OCT, OCTA and FAZ measurement metrics were calculated to assess the diagnostic ability for glaucoma.ResultsMacular GCIPL thickness had a moderate correlation with the macular SVD in the inferonasal sector (r = 0.426, P = 0.008). In addition, there was a strong correlation between inferonasal sector of macular vessel density and 5,6,7,8 clock-hour regions of the pRNFL thicknesses (all r > 0.5). Inferoinferior sector of macular SVD and 6,7 clock-hour regions of pRNFL thicknesses also had strong correlation (all r > 0.5). The AUCs of macular SVD ranged between 0.61 (superonasal sector) and 0.76 (inferoinferior sector). The FAZ circularity index showed the highest diagnostic power (AUC = 0.94;95% CI, 0.85–0.99), followed by superotemporal sector of macular GCIPL thicknesses (0.93;95% CI,0.83–0.98).ConclusionsSector of macular SVD not only had a spatial positional correlation with corresponding macular GCIPL thickness, but also with clock-hour regional pRNFL thicknesses in PACG eyes. FAZ circulation index might be a useful diagnostic parameter.

목적: 당뇨병 환자와 정상인에서 스펙트럼 영역 빛간섭 단층촬영(Carl Zeiss Meditec, Dublin, CA)을 통한 신경절 세포-내망상층 및망막신경섬유층 두께의 차이에 대하여 분석한다. 대상과 방법: 정상안 92안과 당뇨안 42안을 대상으로 스펙트럼 영역 빛간섭단층촬영을 시행하여 망막신경섬유층 두께와 신경절 세포-내망상층 두께의 차이를 비교 분석하였다. 결과: 정상군 92명, 당뇨망막병증이 없는 당뇨환자 22명, 당뇨망막병증이 있는 당뇨환자 26명으로 각 군을 나누어 분석한 결과 당뇨유무나 당뇨망막병증 유무는 망막신경섬유층 두께 차이에 영향을 주지 않았다. 신경절 세포-내망상층 두께는 당뇨가 있는 환자에서,그리고 당뇨망막병증이 있는 환자에서 더욱 얇아지는 경향이 있었으며 특히 위쪽 망막 구역에서 정상군 82.24 ± 7.21 μm, 당뇨망막병증이 없는 당뇨환자군 81.86 ± 9.53 μm, 당뇨망막병증이 있는 당뇨환자군 76.77 ± 14.13 μm로 유의하게 감소하였다(p=0.029). 결론: 당뇨와 당뇨망막병증에 의한 영향에 의해 망막 신경절 세포의 두께 감소가 유발되며 이러한 변화는 특히 위쪽 망막에서 먼저일어나는 것을 확인하였다.

The purpose of this study was to evaluate macular ganglion cell layer-inner plexiform layer (GCL-IPL) and choroidal thickness in early age-related macular degeneration (AMD) in eyes with subretinal drusenoid deposits (SDD). Comprehensive ophthalmological examination was performed. Near infrared reflectance and raster images using enhanced depth imaging were acquired with spectral domain optical coherence tomography. Drusen and SDD were diagnosed based on raster scans and near infrared reflectance. GCL-IPL maps were generated with automated segmentation and choroidal thickness maps were obtained by manually delineating the choroid-scleral boundary. Forty-eight eyes from 48 patients (mean age 77.5 ± 5.7, range 68-90 years) with a diagnosis of early AMD and 42 eyes of 42 age-matched control subjects (mean age 76.9 ± 5.7, range 67-88 years) were included. Of these, 28 eyes (58.3%) had drusen alone, 4 eyes (8.3%) had SDD alone, and 16 eyes (33.3%) had drusen associated with SDD. Compared with controls, average choroidal thickness was significantly decreased in AMD eyes (P < 0.05). There was no significant difference in choroidal thickness in eyes with SDD with respect to those with drusen alone. GCL-IPL thickness was reduced in an annular pattern at the 3 and 6 mm macular areas in AMD patients with respect to controls (P < 0.05). GCL-IPL thickness at 3 mm was significantly reduced in eyes with SDD with respect to those with drusen alone (P = 0.03). The GCL-IPL is reduced in thickness with an annular pattern in early AMD and is significantly thinner in eyes with SDD.

ImportanceEfforts are underway to incorporate retinal neurodegeneration in the diabetic retinopathy severity scale. However, there is no established measure to quantify diabetic retinal neurodegeneration (DRN).ObjectiveWe compared total retinal, macular retinal nerve fiber layer (mRNFL) and ganglion cell-inner plexiform layer (GC-IPL) thickness among participants with and without diabetes (DM) in a population-based cohort.Design/setting/participantsCross-sectional analysis, using the UK Biobank data resource. Separate general linear mixed models (GLMM) were created using DM and glycated hemoglobin as predictor variables for retinal thickness. Sub-analyses included comparing thickness measurements for patients with no/mild diabetic retinopathy (DR) and evaluating factors associated with retinal thickness in participants with and without diabetes. Factors found to be significantly associated with DM or thickness were included in a multiple GLMM.ExposureDiagnosis of DM was determined via self-report of diagnosis, medication use, DM-related complications or glycated hemoglobin level of ≥ 6.5%.Main outcomes and measuresTotal retinal, mRNFL and GC-IPL thickness.Results74,422 participants (69,985 with no DM; 4,437 with DM) were included. Median age was 59 years, 46% were men and 92% were white. Participants with DM had lower total retinal thickness (-4.57 μm, 95% CI: -5.00, -4.14; p<0.001), GC-IPL thickness (-1.73 μm, 95% CI: -1.86, -1.59; p<0.001) and mRNFL thickness (-0.68 μm, 95% CI: -0.81, -0.54; p<0.001) compared to those without DM. After adjusting for co-variates, in the GLMM, total retinal thickness was 1.99 um lower (95% CI: -2.47, -1.50; p<0.001) and GC-IPL was 1.02 μm lower (95% CI: -1.18, -0.87; p<0.001) among those with DM compared to without. mRNFL was no longer significantly different (p = 0.369). GC-IPL remained significantly lower, after adjusting for co-variates, among those with DM compared to those without DM when including only participants with no/mild DR (-0.80 μm, 95% CI: -0.98, -0.62; p<0.001). Total retinal thickness decreased 0.40 μm (95% CI: -0.61, -0.20; p<0.001), mRNFL thickness increased 0.20 μm (95% CI: 0.14, 0.27; p<0.001) and GC-IPL decreased 0.26 μm (95% CI: -0.33, -0.20; p<0.001) per unit increase in A1c after adjusting for co-variates. Among participants with diabetes, age, DR grade, ethnicity, body mass index, glaucoma, spherical equivalent, and visual acuity were significantly associated with GC-IPL thickness.ConclusionGC-IPL was thinner among participants with DM, compared to without DM. This difference persisted after adjusting for confounding variables and when considering only those with no/mild DR. This confirms that GC-IPL thinning occurs early in DM and can serve as a useful marker of DRN.

To study inner retinal neurodegeneration in Diabetes Mellitus using spectral domain optical coherence tomography (OCT). This cross-sectional study included 40 eyes of age matched healthy subjects (group N), 40 eyes of diabetic patients without diabetic retinopathy (group D) and 160 eyes with diabetic retinopathy (group R) having 40 each in subgroups R1 (mild), R2 (moderate), R3 (severe/very severe) non-proliferative stages and R4 (proliferative stage). Spectral domain OCT was used to measure the ganglion cell-inner plexiform layer (GC-IPL) thickness and retinal nerve fibre layer (RNFL) thickness. The average GC-IPL thickness was significantly lower, both in groups D (p = 0.005) and R (p = 0.009), when compared with group N. The minimum GC-IPL thickness was also significantly lower in groups D (p < 0.001) and R (p < 0.001). There was no statistically significant difference in the average RNFL thickness among the groups. The minimum RNFL thickness was significantly lesser in group D (p = 0.027). The minimum RNFL thickness had a strongly negative correlation with the severity of DR (R = -0.828; p = 0.042). The thinning of both GC-IPL and RNFL was most pronounced in subgroup R4. There is a significant reduction in the GC-IPL thickness and the RNFL thickness in diabetes even before the onset of DR. The changes in both GC-IPL thickness and RNFL thickness are most pronounced after the onset of PDR. There is a strongly negative correlation between the minimum RNFL thickness with the severity of DR.

To quantify retinal microvasculature within the macular ganglion cell-inner plexiform layer (GCIPL) in primary open-angle glaucoma (POAG) and normal eyes, determine association of vessel parameters with structural and functional measures, and report diagnostic accuracy of vessel parameters. POAG and normal patients underwent 6×6 mm macula scans [Angioplex optical coherence tomography angiography (OCTA); Cirrus HD-OCT 5000]; and Humphrey Field Analyzer II-i 24-2 visual field (VF). Prototype software performed semiautomatic segmentation to create GCIPL en face images, and quantified vessel area density (VAD), vessel skeleton density (VSD), and vessel complexity index (VCI) for the macula (globally, hemifields, and 6 focal sectors). Linear regression assessed association of OCTA parameters with VF mean deviation (MD) and GCIPL thickness globally and focally. A total of 34 POAG and 21 normal eyes were studied. VAD, VSD, and VCI were reduced in POAG versus normal (0.463 vs. 0.486, P=0.00029; 0.230 vs. 0.219, P=0.0014; 1.15 vs. 1.09, P=0.0044, respectively), with a trend of worsening with increased POAG severity. Reduced global VF MD was associated with reduced VAD and VCI, controlling for age and intereye correlation (P=0.0060, 0.0080; R=0.205, 0.211). Both superior and inferior hemifield MD were associated with corresponding VAD, VSD, and VCI (all P<0.007; R ranged from 0.12 to 0.29). Global GCIPL thickness was not associated with global OCTA parameters, and only inferior sector GCIPL thickness was associated with corresponding VAD, VSD, and VCI (P<0.05; R ranged from 0.15 to 0.16). Area under curves for VAD, VSD, and VCI were fair to good (0.83, 0.79, 0.82; respectively; P<0.0001). Glaucomatous eyes had reduced GCIPL microcirculation. OCTA parameters had stronger associations with functional rather than structural measures of glaucoma. This observation deserves further study.

Optic coherence tomography imaging in preperimetric open angle glaucoma (OAG) differed between young-age-onset and old-age-onset eyes. Inferior and superior quadrants were thinner in young and old-age-onset eyes, respectively. Understanding the specific patterns of early glaucomatous damage based on age-at-onset may improve glaucoma diagnosis and monitoring. To investigate the patterns of retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thinning in preperimetric OAG by optical coherence tomography based on age at onset ("young-age onset (<40y)" vs. "old-age onset (≥40y)". The RNFL and GCIPL deviation images were acquired by Cirrus HD-optical coherence tomography, and overlaid, thus converted to a "deviation frequency map", respectively. The topographic thinning patterns and parameters of RNFL and GCIPL thickness measurements were compared. A total of 194 eyes of 194 patients with preperimetric OAG and 97 eyes of 97 age-matched normal subjects were analyzed. Young-age-onset eyes of preperimetric OAG mainly had RNFL defects inferotemporally (264-296 degrees) with GCIPL defects in the inferior region (213-357 degrees). Old-age-onset preperimetric OAG eyes had RNFL defects inferotemporally (266-294°) and superotemporally (33-67 degrees), with GCIPL defects in the inferior and superior regions (206-360 degrees, 0-22 degrees). The inferior quadrant of RNFL and GCIPL thicknesses were significantly thinner in young-age-onset eyes compared with old-age-onset eyes ( P =0.012, 0.016), while the superior quadrant of those were significantly thinner in the old-age-onset eyes ( P =0.003, 0.005). Young-age-onset and old-age-onset eyes of preperimetric OAG present different specific patterns of RNFL and GCIPL thinning.