RNFL thickness in MS‐associated acute optic neuritis using SD‐OCT: critical interpretation and limitations

Purpose: Axonal loss is considered a key prognostic factor in diagnosing and monitoring the progress of multiple sclerosis (MS). The purpose of our research was to determine whether the measurement of retinal nerve fibre layer thickness (RNFLT) as measured with high‐resolution spectral‐domain optical coherence tomography (SD‐OCT) differs between optic nerve injury following acute optic neuritis (ON) or following unregistered subclinical axonal damage in patients with MS. Methods: High‐resolution SD‐OCT measurements of RNFLT were initially carried out in the acute phase of ON and again after 3 months, in 25 patients with clinical definite MS and 25 sex‐ and age‐matched healthy controls, all at the University Eye Hospital, Vienna. Results: Conventional OCT‐based RNFLT analysis correctly identified all three patients with initial RNFL swelling. However, only two of three acute ON eyes with a history of ON were registered with RNFLT decrease in seven peripapillary sectors (PPs). The remaining have only been revealed using RNFLT symmetry comparison. Two of 22 (9%) first‐episode ON eyes were labelled as pathologic. The number and metric RNFL values of pathologically labelled PPs remained unchanged after 3 months. Our age‐ and sex‐match‐based measurement model, with patients with MS being plotted individually and towards the fellow eye, identified all acute ON eyes (with a history of prior ON) with RNFLT reduction in 11 PPs. A global RNFL loss was registered in 36.4% (eight of 22 eyes). However, in 72%, or 16 of 22 ON eyes presenting with first episode of acute ON, a segmental RNFL loss was initially registered in 39 PPs upon baseline examination. The number of PPs with identified axonal decrease increased to a total of 48 PPs within the observational period. Conclusions: Spectral‐domain optical coherence tomography imaging of identical scanning locations, combined with an optimized scan centring around the optic disc, offers the technological potential of detecting prior, subtle, clinically unregistered optic nerve injury within MS individuals. Significant discrepancy in RNFLT to the potential ON eye may be achieved by comparing OCT metrics with the fellow eye and a sufficient number of age and sex‐matched controls.     

Comparison of retinal nerve fiber layer and macular thickness measurements with Stratus OCT and OPKO/OTI OCT devices in healthy subjects

AIM: To compare retinal nerve fiber layer (RNFL) and macular thickness measurements obtained with the Stratus optical coherence tomography (OCT) and OPKO/OTI OCT devices. METHODS: Included in the study were 59 eyes of 30 participants. All measurements for each eye were done on the same day with both devices. Student’s paired t-tests were used to compare the central macular thickness and RNFL measurements of the Stratus OCT and OPKO/OTI OCT. Pearson correlation was used to assess the relationship between the devices. Coefficient of variation (COV) was calculated to assess intersession repeatability. RESULTS: Using both the Stratus OCT and OPKO/OTI OCT, respectively, the measured mean average RNFL thicknesses were 98.9±11.1 μm and 115.1±9.6 μm (P=0.001), and the measured mean central retinal thicknesses (CRT) were 196.2±18.8 μm and 204.5±21.1 μm (P<0.001). Measured by the two devices, the RNFL thickness values were correlated in all quadrants, as were the retinal thickness values except the inferior outer sector. COV for average RNFL and CRT thickness were 2.9% and 4.6% for Stratus OCT, and 2.1% and 4.2% for OPKO/OTI OCT, respectively. CONCLUSION: We found good reproducibility of RNFL and retina thickness measurements for both Stratus OCT and OPKO/OTI OCT devices. However, even though the two OCT systems provided statistically correlated results, the values for both RNFL and macular thickness were statistically different. RNFL and macular thickness measurements with the OPKO/OTI OCT were higher than that of the Stratus OCT; therefore, the two OCT systems cannot be used interchangeably for the measurements of RNFL and macular thickness.     

The relationship between the optical density of cataract and its influence on retinal nerve fibre layer thickness measured with spectral domain optical coherence tomography

Purpose: The purpose of this study was to model the influence of cataract on Spectral Domain Optical Coherence Tomography (SDOCT) image quality and Retinal Nerve Fibre Layer (RNFL) thickness measurements. Methods: SDOCT images, made with two different devices (3DOCT‐1000, Topcon and Cirrus HD‐OCT), before and after cataract surgery were compared and judged against measurements from normal subjects using artificial filters simulating the effects of cataract. Optical density of the images was calculated based on a mathematical model described previously. Results: In total, forty‐eight eyes were included for pre‐ and postoperative cataract extraction measurements. OCT image quality significantly (p < 0.001) improved postoperative and postoperative RNFL thickness was significantly (p < 0.001) thicker in both groups of patients. The measurements using artificial filters showed a rather precise linear relation between change in filter induced optical density and change in RNFL thickness (R = 0.941, p < 0.001 for 3DOCT‐1000 and R = 0.785, p < 0.001 for Cirrus HD‐OCT). For the patient groups, the relation was less marked, 3DOCT‐1000 R_s = 0.697, p < 0.03 and Cirrus HD‐OCT R_s = 0.444, p < 0.03. The predictive potential based on the found linear relationship between OCT‐effective optical density of cataract and the cataract‐induced underestimation was however limited, and mean difference ± SD between predicted and measured RNFL thickness were 1.68 ± 7.55 (3DOCT‐1000) and 3.71 ± 2.97 (Cirrus HD‐OCT) micron. Conclusions: A linear relationship exists between OCT‐effective optical density of cataract and underestimation of RNFL thickness measured with OCT. This finding holds promise to correct for cataract‐induced changes in RNFL measurements, but will differ for each type of OCT device.     

Comparison of retinal nerve fiber layer thickness between Stratus and Spectralis OCT

Purpose

To compare the peripapillary retinal nerve fiber layer (RNFL) thickness of normal patients and those with various glaucoma diseases by time domain (Stratus) and spectral domain (Spectralis) optical coherence tomography (OCT).

Methods

The RNFL thickness as measured by the Stratus and Spectral OCT was compared (paired t-test). The relationship and agreement of RNFL thickness between the two OCT modalities were evaluated by Pearson correlation, Bland-Altman plot, and area under the receiver operating characteristic curve.

Results

Two-hundred seventeen eyes of 217 patients, including twenty-four normal eyes, ninety-one glaucoma suspects, seventy-six normal tension glaucoma cases, and twenty-six primary open angle glaucoma cases (POAG) were analyzed. The peripapillary RNFL thicknesses as measured by Stratus OCT were significantly greater than those measured by Spectralis OCT. However, in quadrant comparisons, the temporal RNFL thickness obtained using Stratus OCT were significantly less than those obtained using Spectralis OCT. Correlations between RNFL parameters were strong (Pearson correlation coefficient for mean RNFL thickness = 0.88); a high degree of correlation was found in the POAG group. Bland-Altman plotting demonstrated that agreement in the temporal quadrant was greater than any other quadrant.

Conclusions

Both OCT systems were highly correlated and demonstrated strong agreement. However, absolute measurements of peripapillary RNFL thickness differed between Stratus OCT and Spectralis OCT. Thus, measurements with these instruments should not be considered interchangeable. The temporal quadrant was the only sector where RNFL thickness as measured by Spectralis OCT was greater than by Stratus OCT; this demonstrated greater agreement than other sectors.     

屈光不正儿童后极部视网膜厚度及视盘周围神经纤维层厚度的观察

目的：利用频域光学相干断层扫描仪(SD-OCT)对屈光不正儿童后极部视网膜厚度及视网膜神经纤维层(retinal nerve fiber layer,RNFL)厚度进行测量,探讨年龄、屈光度与视网膜厚度之间的相关性。

方法：收集2016-02/2017-02在复旦大学附属华山北院眼科门诊就诊的5～15岁屈光不正儿童96例192眼,应用SD-OCT设备对受检者视盘周围RNFL厚度和后极部视网膜厚度(posterior pole retinal thickness,PPRT),包括后极部20°范围内以视盘和黄斑连线为界,分为上方、下方、平均PPRT及距黄斑中心凹1mm视网膜厚度进行检测,并分析年龄、屈光度与PPRT及RNFL厚度的相关性。

结果：SD-OCT检查示,本组病例距黄斑中心凹1mm视网膜厚度为252.72±13.87μm,平均PPRT为294.02±8.70μm,上方PPRT为294.53±9.11μm,下方PPRT为293.53±9.50μm,RNFL厚度为105.75±10.60μm。年龄与距黄斑中心凹1mm视网膜厚度呈正相关,屈光度与PPRT及RNFL厚度均呈正相关。

结论：SD-OCT能够准确测量儿童后极部视网膜厚度,年龄、屈光度与视网膜厚度及RNFL厚度具有相关性。     

Cirrus HD OCT检测近视眼视网膜神经纤维层厚度的研究

目的：应用Cirrus HD OCT检测近视眼视网膜神纤维层厚度,探讨近视眼神经纤维层厚度分布特点及其与屈光度的关系。 方法：将近视眼106例196眼分为低、中、高度近视组和正常对照组38例60眼,应用Cirrus HD OCT进行以视盘为中心,直径3.46 mm圆周的RNFL厚度测量,计算各组平均、各象限及各钟点RNFL厚度,各近视组分别与正常对照组对比,研究近视眼RNFL厚度与屈光度的关系。 结果：各近视组平均、上方象限及下方象限RNFL厚度较正常对照组变薄,其中中度、高度近视与正常对照组相比有统计学差异（ P〈0.05）,鼻侧象限RNFL厚度变薄,无统计学显著性差异（ P〉0.05）,颞侧象限RNFL厚度增加,有统计学差异（ P〈0.05）;各近视组2：00,6：00,12：00位RNFL厚度较正常对照组变薄,有统计学差异（ P〈0.05）,8：00,9：00,10：00位RNFL厚度较正常对照组增加,有统计学差异（ P〈0.05）,中、高度近视1：00,5：00位厚度较正常对照组变薄,有统计学差异（P〈0.05）。 结论：近视眼平均、上方及下方象限、2：00,6：00,12：00位RNFL厚度较正常对照组变薄,颞侧象限、8：00,9：00,10：00位RNFL厚度较正常对照组相比明显增加,这是近视眼RNFL厚度的特点,当临床出现RNFL厚度异常时,应考虑屈光度的影响,综合评价其临床意义;近视眼7：00,8：00,10：00,11：00位RNFL厚度与正常对照组相比均未变薄,出现异常变薄时,应考虑青光眼可能。     

Peripapillary retinal nerve fiber layer thickness in patients with iron deficiency anemia

Purpose:To evaluate the effect of iron deficiency anemia (IDA) on peripapillary retinal nerve fiber layer (RNFL) thickness with optical coherence tomography (OCT).Results:Average ages of 102 patients and 49 control subjects were 35.76 ± 10.112 (range, 18–66) years, and 36.08 ± 8.416 (range, 19–57) years (P = 0.850), respectively. The average RNFL thickness was 94.67 ± 9.380 in the anemia group, and 100.22 ± 9.12 in the control group (P = 0.001). Temporal, nasal, and lower quadrant average RNFL thicknesses of IDA group were thinner than the control group (P = 0.001, P = 0.013, P = 0.008). Upper quadrant RNFL thicknesses in IDA and control groups were similar. Correlation analysis revealed positive correlation between mean RNFL thickness and hemoglobin (r = 0.273), iron (r = 0.177), ferritin (r = 0.163), and transferrin saturations (r = 0.185), while a negative correlation was found between total iron binding capacity (r = −0.199) and mean RNFL thickness.Conclusions:Peripapillary RNFL thickness measured by OCT is thinner in adult female patients with IDA. It may have a significant influence on the management of many disorders such as glaucoma and neuro-ophthalmological diseases.     

Optical coherence tomography with or without enhanced depth imaging for peripapillary retinal nerve fiber layer and choroidal thickness

AIM: To assess peripapillary retinal nerve fiber layer (RNFL) and choroidal thickness obtained with enhanced depth imaging (EDI) mode compared with those obtained without EDI mode using Heidelberg Spectralis optical coherence tomography (OCT). METHODS: Fifty eyes of 25 normal healthy subjects and 32 eyes of 20 patients with different eye diseases were included in the study. All subjects underwent 3.4 mm diameter peripapillary circular OCT scan centered on the optic disc using both the conventional and the EDI OCT protocols. The visualization of RNFL and choroidoscleral junction was assessed using an ordinal scoring scale. The paired t-test, intraclass correlation coefficient (ICC), 95% limits of agreement (LoA), and Bland and Altman plots were used to test the agreement of measurements. RESULTS: The visibility score of RNFL obtained with and without EDI was of no significant difference (P=0.532), the visualization of choroidoscleral junction was better using EDI protocol than conventional protocol (P<0.001). Peripapillary RNFL thickness obtained with EDI was slightly thicker than that obtained without EDI (103.25±9.42 μm vs 101.87±8.78 μm, P=0.010). The ICC of the two protocols was excellent with the value of 0.867 to 0.924, the 95% LoA of global RNFL thickness was between -10.0 to 7.4 μm. Peripapillary choroidal thickness obtained with EDI was slightly thinner than that obtained without EDI (147.23±51.04 μm vs 150.90±51.84 μm, P<0.001). The ICC was also excellent with the value of 0.960 to 0.987, the 95% LoA of global choroidal thickness was between -12.5 to 19.8 μm. CONCLUSION: Peripapillary circular OCT scan with or without EDI mode shows comparable results in the measurement of peripapillary RNFL and choroidal thickness.     

视盘周围血管密度和视网膜神经纤维层厚度与眼轴长度和屈光度的相关性分析

目的应用光学相干断层扫描血管成像(optical coherence tomography angiography,OCTA)观察视盘周围血管密度和视网膜神经纤维层(retinal nerve fibre layer,RNFL)厚度与眼轴长度和屈光度之间的关系。方法纳入受试者40名40眼,测量屈光度和眼轴长度,通过OCTA检查各上方、下方、鼻侧、颞侧四个象限及整体视盘周围血管密度,测量相应区域的视盘周围RNFL厚度,分析两者之间及两者分别与眼轴长度和屈光度之间的相关性。结果视盘周围整体RNFL厚度与眼轴长度呈显著负相关(r=-0.760,P<0.001),与屈光度呈显著正相关(r=0.625,P<0.001)。且上方、下方和鼻侧象限的视盘周围RNFL厚度均与眼轴长度呈显著负相关(r=-0.506、-0.667、-0.700,均为P<0.01),与屈光度呈显著正相关(r=0.409、0.506、0.556,均为P<0.01)。视盘周围整体及颞侧象限的血管密度与眼轴长度均呈显著负相关(均为P<0.05),与屈光度均呈显著正相关(均为P<0.05)。视盘周...     

Structure–function relationship among three types of spectral‐domain optical coherent tomography instruments in measuring parapapillary retinal nerve fibre layer thickness

Purpose:  To compare the relationships of parapapillary retinal nerve fibre layer (RNFL) thickness among three spectral‐domain optical coherence tomography (SD‐OCT) instruments with visual field sensitivity (VFS). Methods:  One hundred and thirteen eyes of 113 Japanese subjects with glaucoma (mean deviation in standard automated perimetry = ?8.9 ± 6.7 dB) were imaged by Cirrus, RTVue and 3D OCT. The average hemi‐superior and hemi‐inferior RNFL thicknesses were obtained. In addition, the structure–function relationship using two retinotopic maps that consisted of six or nine sectors was also evaluated. Decibel (dB) scale and 1/Lamert (1/L) were used to express VFS. RNFL thickness correlation with corresponding VFS in visual field sectors was compared among the three instruments. Background RNFL thickness (non‐neuronal tissue) for each instrument was estimated using a linear regression model at 1/L = 0. Results:  The correlation between the average hemi‐superior and hemi‐inferior RNFL thickness in the three SD‐OCT instruments with corresponding VFS was similar. In the analysis of retinotopic maps, 3D OCT showed a higher correlation in superotemporal sectors than RTVue, whereas RTVue had a stronger relationship in the nasal sector than Cirrus. The background RNFL thickness extrapolated was approximately 60% that of normal eyes in all the instruments. Conclusions:  The three SD‐OCT showed similar overall correspondence with VFS with a partially discordant retinotopic relationship. RNFL measured with any SD‐OCT devices likely contains non‐neuronal tissue, comprising 60% of its thickness.     

Normative database of retinal nerve fiber layer and macular retinal thickness in a Thai population

Purpose  To investigate the distribution of retinal nerve fiber layer (RNFL) and macular retinal thickness measured by optical coherence tomography (OCT) in a Thai population. Methods  We studied one eye each of 250 healthy subjects [age ≥ 18 years; spherical refractive error within ±6 diopters (D); astigmatism ≤3 D; no ocular pathology]. A complete eye examination, standard automated perimetry, and fast RNFL and macular thickness measurement by OCT were performed, and a disc photograph was taken. The distributions of both thicknesses, including their relationship with demographic data, were analyzed. Results  The mean ± SD age of the study population was 44.7 ± 12.2 years. The mean ± SD RNFL thickness was 109.3 ± 10.5 m, which was 10% thicker than that in the OCT normative database. RNFL decreased 2.3 m per decade (P < 0.001). Sex and spherical equivalent were not associated with RNFL thinning. The mean ± SD central foveal thickness was 183.2 ± 1.3 m. The macular thickness in the outer area was significantly thinner than that in the inner area (P < 0.001). The temporal regions were the thinnest among the four quadrants (P < 0.001). Thinning of all macular areas, except the center, was found to be associated with advancing age (P < 0.05). Conclusions  RNFL thickness in the measured Thai population was about 10% thicker than that in the original normative database. Macular thickness and RNFL thickness in the superior and inferior quadrants decreased with advancing age. Presented at the 6^th International Glaucoma Society Meeting, 28–31 March 2007, Athens, Greece     

[In Press] Optical coherence tomography with or without enhanced depth imaging for peripapillary retinal nerve fiber layer and choroidal thickness

AIM: To assess peripapillary retinal nerve fiber layer (RNFL) and choroidal thickness obtained with enhanced depth imaging (EDI) mode compared with those obtained without EDI mode using Heidelberg Spectralis optical coherence tomography (OCT). METHODS: Fifty eyes of 25 normal healthy subjects and 32 eyes of 20 patients with different eye diseases were included in the study. All subjects underwent 3.4 mm diameter peripapillary circular OCT scan centered on the optic disc using both the conventional and the EDI OCT protocols. The visualization of RNFL and choroidoscleral junction was assessed using an ordinal scoring scale. The paired t-test, intraclass correlation coefficient (ICC), 95% limits of agreement (LoA), and Bland and Altman plots were used to test the agreement of measurements. RESULTS: The visibility score of RNFL obtained with and without EDI was of no significant difference(P=0.532), the visualization of choroidoscleral junction was better using EDI protocol than conventional protocol (P＜0.001). Peripapillary RNFL thickness obtained with EDI was slightly thicker than that obtained without EDI (103.25±9.42 μm vs 101.87±8.78 μm, P=0.010). The ICC of the two protocols was excellent with the value of 0.867 to 0.924, the 95% LoA of global RNFL thickness was between -10.0 to 7.4 μm. Peripapillary choroidal thickness obtained with EDI was slightly thinner than that obtained without EDI (147.23±51.04 μm vs 150.90±51.84 μm, P＜0.001). The ICC was also excellent with the value of 0.960 to 0.987, the 95% LoA of global choroidal thickness was between -12.5 to 19.8 μm. CONCLUSION: Peripapillary circular OCT scan with or without EDI mode shows comparable results in the measurement of peripapillary RNFL and choroidal thickness.     

Correlation between retinal nerve fibre layer thickness and retinal sensitivity

Purpose: To evaluate the relationship between retinal nerve fibre layer (RNFL) thickness measured by optical coherence tomography (OCT) and light threshold values obtained with the Micro Perimeter 1 (MP1). Methods: Forty‐nine normal subjects and 37 glaucoma patients were included. Thickness of the RNFL around the optic disc was measured with Stratus OCT scans, and static threshold perimetry was performed with the MP1 at the same visit. Total average and mean 12‐clock‐hour RNFL thickness were measured with Stratus OCT. An automated 4‐2‐1 staircase strategy with Goldmann III stimuli was used for MP1. The correspondence between Stratus OCT and MP1 RNFL measurements in each clock‐hour was best fit by a second‐order polynomial. Results: Average RNFL thickness in the normal group was significantly higher than that in the glaucoma group in each clock hour. Comparing the normal and glaucomatous groups, retinal sensitivity differed significantly at 6, 7, 8 and 11 o’clock. In these regions, structure–function relationships were generally stronger than in other regions. Conclusions: Structure–function associations may be strong when loss of nerve fibres is severe. However, significant reduction in retinal sensitivity does not emerge until the atrophy of nerve fibres is severe.     

Evaluation of retinal nerve fiber layer thickness profile in thyroid ophthalmopathy without optic nerve dysfunction

AIM: To evaluate retinal nerve fiber layer (RNFL) thickness profile in patients of thyroid ophthalmopathy with no clinical signs of optic nerve dysfunction. METHODS: A prospective, case-control, observational study conducted at a tertiary care centre. Inclusion criteria consisted of patients with eyelid retraction in association with any one of: biochemical thyroid dysfunction, exophthalmos, or extraocular muscle involvement; or thyroid dysfunction in association with either exophthalmos or extra-ocular muscle involvement; or a clinical activity score (CAS)>3/7. Two measurements of RNFL thickness were done for each eye, by Cirrus HD-optical coherence tomography 6mo apart. RESULTS: Mean age of the sample was 38.75y (range 13-70y) with 18 males and 22 females. Average RNFL thickness at first visit was 92.06±12.44 µm, significantly lower than control group (101.28±6.64 µm) (P=0.0001). Thickness of inferior quadrant decreased from 118.2±21.27 µm to 115.0±22.27 µm after 6mo (P=0.02). There was no correlation between the change in CAS and RNFL thickness. CONCLUSION: Decreased RNFL thickness is an important feature of thyroid orbitopathy, which is an inherent outcome of compressive optic neuropathy of any etiology. Subclinical RNFL damage continues in the absence of clinical activity of the disease. RNFL evaluation is essential in Grave’s disease and active intervention may be warranted in the presence of significant damage.