Changes of Optical Coherence Tomography Parameters after Cataract Surgery in Primary Open-Angle Glaucoma Eyes.

PURPOSE: To investigate the impact of uncomplicated cataract surgery on the measurement of Bruch's membrane opening-minimum rim width (BMO-MRW) and retinal nerve fiber layer thickness (RNFLT) using spectral domain optical coherence tomography (SD-OCT) in primary open-angle glaucoma (POAG) patients. METHODS: This retrospective study included 63 eyes of 63 patients, including 32 POAG eyes and 31 normal eyes who underwent uneventful cataract surgery and follow-up for at least 6 months. Using SD-OCT, BMO-MRW and RNFLT were measured preoperatively and postoperatively at 6 months. Paired t-test was used to compare intraocular pressure (IOP), BMO-MRW, RNFLT, and image quality before and after surgery. These parameters and their changes were compared between POAG and normal groups. Univariate and multivariate linear regression analyses were performed to determine the factors associated with the postoperative change (Δ) in RNFLT and BMO-MRW. RESULTS: BMO-MRW and RNFLT were significantly increased and IOP was decreased after phacoemulsification in both groups (p < 0.001, respectively). The ΔRNFLT was significantly greater in POAG eyes compared with the normal eyes (p < 0.001). The ΔRNFLT was associated with the postoperative IOP reduction and glaucoma diagnosis (p < 0.001 and p = 0.001, respectively). In the normal group, only the ΔIOP had a significant influence on the ΔRNFLT (p = 0.003), but in the POAG group, not only the ΔIOP (p = 0.044) but also preoperative visual field mean deviation (p = 0.029) showed a significant influence. The ΔBMO-MRW showed no difference between POAG and normal eyes. CONCLUSIONS: The postoperative increase of RNFLT was significantly greater in the POAG group, and the postoperative increase of RNFLT was associated with the preoperative visual field mean deviation and ΔIOP in POAG eyes and with the ΔIOP in normal eyes. Our results imply that RNFLT is more affected than BMO-MRW in POAG eyes compared to normal eyes by cataract surgery.

Deep learning classification of early normal-tension glaucoma and glaucoma suspect eyes using Bruch's membrane opening-based disc photography.

Purpose: We aimed to investigate the performance of a deep learning model to discriminate early normal-tension glaucoma (NTG) from glaucoma suspect (GS) eyes using Bruch's membrane opening (BMO)-based optic disc photography. Methods: 501 subjects in total were included in this cross-sectional study, including 255 GS eyes and 246 eyes of early NTG patients. BMO-based optic disc photography (BMO overview) was obtained from spectral-domain optical coherence tomography (OCT). The convolutional neural networks (CNN) model built from scratch was used to classify between early NTG and GS. For diagnostic performances of the model, the accuracy and the area under the curve (AUC) of the receiver operating characteristic curve (ROC) were evaluated in the test set. Results: The baseline demographics were age, 48.01 ± 13.03 years in GS, 54.48 ± 11.28 years in NTG (p = 0.000); mean deviation, -0.73 ± 2.10 dB in GS, -2.80 ± 2.40 dB in NTG (p = 0.000); and intraocular pressure, 14.92 ± 2.62 mmHg in GS, 14.79 ± 2.61 mmHg in NTG (p = 0.624). Our CNN model showed the mean AUC of 0.94 (0.83-1.00) and the mean accuracy of 0.91 (0.82-0.98) with 10-fold cross validation for discriminating between early NTG and GS. Conclusion: The performance of the CNN model using BMO-based optic disc photography was considerably good in classifying early NTG from GS. This new disc photography of BMO overview can aid in the diagnosis of early glaucoma.

Impact of Epiretinal Membrane on Optical Coherence Tomography Tools Used for Monitoring Glaucoma.

BACKGROUND: Retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) measurements can be influenced by many factors including the presence of concomitant retinal diseases. The aim of this study it to assess the impact of epiretinal membrane (ERM) on RNFL and GCL assessment using optical coherence tomography (OCT). METHODS: GCL, peripapillary RNFL (pRNFL), and Bruch's Membrane Opening Minimum Rim Width (BMO-MRW) thicknesses were analysed using an SD-OCT (Spectralis OCT) in eyes with idiopathic ERM and compared with a control group. RESULTS: 161 eyes were included, 73 eyes in the control group and 88 eyes with idiopathic ERM. The pRNFL analysis revealed a statistically significant difference between the two groups in overall and temporal sector thicknesses. For GCL thickness report, the percentage of scans in which the GCL was erroneously segmented by automatic segmentation was assessed for each eye. A statistically significant difference was found in all sectors (p < 0.001), with the exception of external nasal sector. A statistically significant difference (p < 0.001) in the GCL total volume report was found in ERM group compared to the control group. For MRW at BMO analysis, there was no statistically significant difference in MRW thickness in any sector. CONCLUSION: In eyes with ERM, the GCL and pRNFL analysis seemed affected by the morphological retinal layers' modification. MRW-BMO did not appear to be directly affected by the presence of ERM.

Bruch membrane opening-minimum rim width and retinal nerve fiber layer thickness in myopic children.

BACKGROUND/OBJECTIVES: It is debatable whether the decrease of retinal nerve fiber layer (RNFL) thickness in myopic people under 18 years of age is due to insufficient measurement techniques or to real physical loss of retinal ganglion cells and axons. Hence, to better understand the relationship between the degree of myopia and the neuroretinal rim (NR), we aim to investigate the NR in the eyes of healthy myopic children using the novel measurement algorithms of spectral-domain optical coherence tomography (SD-OCT). SUBJECTS/METHODS: This prospective, cross-sectional study includes 378 left eyes of 378 (301 female) participants divided into three groups according to their spherical equivalent (SE) refractive error (RE) [Group-1(G1), -1.00 ≤ SE ≤ 1.00 diopters (D); Group-2 (G2), -4.00 ≤ SE < -1.00 D; Group-3 (G3), SE<-4.00 D]. All participants underwent a full ophthalmic examination, including biometric and pachymetric measurements. Standard peripapillary RNFL, as well as the novel algorithms, Bruch's membrane opening-minimum rim width (BMO-MRW), and RNFL acquired using the anatomic positioning system (APS-RNFL) were obtained by SD-OCT. Nasal, temporal, temporal-inferior, temporal-superior, nasal-inferior, nasal-superior sectors' and their general (global) averages were recorded. Rim areas and disc sizes were measured via confocal scanning laser ophthalmoscopy. Global and the six sectors' averages were recorded. RESULTS: G1 consisted of 141 subjects, G2 consisted of 89, and G3 consisted of 48. The sex distribution (p = 0.112) and mean age (p = 0.129) of the groups were similar. The mean global averages of the standard RNFLs were 96 ± 14.4 µ in G1, 93.8 ± 12.9 µ in G2, and 86 ± 11.8 µ in G3. The mean global averages of the APS-RNFLs were 103.9 ± 97 µ in G1, 103.3 ± 10.6 µ in G2, and 102 ± 10.6 µ in G3. The mean global averages of the BMO-MRW were 374.4 ± 57.7 µ in G1, 373.2 ± 62.2 µ in G2, and 351.9 ± 63.9 µ in G3. For the global averages, APS-RNFL and BMO-MRW did not detect any difference between the three groups (p = 0.563, p = 0.089, respectively), but the standard RNFL did (p < 0.001). Standard RNFL and APS-RNFL were found to be well correlated; however, the correlations between BMO-MRW and standard RNFL or APS-RNFL were either absent or very weak. All three methods showed weak but significant negative correlations with high myopic spherical RE, especially those in the standard RNFL. Moderately negative correlations were found between BMO-MRW and disc size in all sectors (highest in the nasal sector; r = -0.387, p < 0.001). However, there was almost no significant relationship between disc size and standard RNFL or APS-RNFL. Moderately significant negative correlations were observed between the groups categorically and standard RNFL in almost all sectors, while this was much less with APS-RNFL and was not observed in almost any sector with BMO-MRW. CONCLUSIONS: When evaluating the NR in healthy myopic children, it was found that, in particular, BMO-MRW and APS-RNFL are less effected by RE degree compared to standard RNFL. BMO-MRW and APS-RNFL should be used on these children to avoid the possible misdiagnosis of glaucoma.

Diagnostic Classification of Bruch's Membrane Opening-Minimum Rim Width and Retinal Nerve Fiber Layer Thickness in Myopic Eyes by Optical Coherence Tomography.

Purpose: This study was conducted in order to compare the diagnostic classification of Bruch's membrane opening-minimum rim width (BMO-MRW) and RNFL thickness in normal myopic subjects by using optical coherence tomography (OCT). Methods: This cross-sectional study involved 75 healthy myopic subjects [spherical equivalent (SE) ≤ -0.5D] from April 2019 to January 2020. One eye of each subject was randomly selected for examination. BMO-MRW and peripapillary RNFL thickness were measured by spectral-domain OCT (Spectralis, Heidelberg Engineering GmbH, Heidelberg, Germany). All the subjects were divided into three groups: low myopic group (SE > -3D), moderate myopic group (-6D < SE ≤ -3D), and high myopic group (SE ≤ -6D). A nonparametric test was used to analyze the difference among groups. Linear regression was used to analyze the relationship between BMO-MRW/RNFL thickness and axial length/spherical equivalent. McNemar test was used to compare the diagnostic classification between BMO-MRW and RNFL thickness. Results: The RNFL thickness classified a significantly higher percentage of eyes as outside normal limits/borderline in at least 1 quadrant (BMO-MRW, 4%; RNFL thickness, 34.67%; p < 0.01). There was no significant correlation between BMO-MRW/RNFL thickness and AL/SE. The low myopia (SE > -3D) had a significantly lower percentage of eyes classified as outside normal limits/borderline in at least 1 quadrant than the moderate myopia (-6D < SE ≤ -3D) and high myopia (SE ≤ -6D) (low myopia, 12.5%; moderate/high myopia, 42.42%/50%; p < 0.05). Conclusion: BMO-MRW had a lower percentage of eyes classified as outside normal limits/borderline in at least 1 quadrant than RNFL thickness in normal myopic subjects. When referring to the diagnostic classification of RNFL thickness in myopic subjects, caution should be exercised in interpreting positive results. Further studies are needed to compare the diagnostic accuracy of these two measurements in myopic glaucoma patients.

Factors Associated with Increased Neuroretinal Rim Thickness Measured Based on Bruch's Membrane Opening-Minimum Rim Width after Trabeculectomy.

PURPOSE: To investigate the factors associated with an increase in the neuroretinal rim (NRR) thickness measured based on Bruch's membrane opening-minimum rim width (BMO-MRW) after trabeculectomy in patients with primary open-angle glaucoma (POAG). METHODS: We analyzed the BMO-MRW using spectral-domain optical coherence tomography (SD-OCT) of patients with POAG who underwent a trabeculectomy for uncontrolled intraocular pressure (IOP) despite maximal IOP reduction treatment. The BMO-MRW was measured before and after trabeculectomy in patients with POAG. Demographic and systemic factors, ocular factors, pre- and post-operative IOP, and visual field parameters were collected, together with SD-OCT measurements. A regression analysis was performed to investigate the factors that affected the change in the BMO-MRW after the trabeculectomy. RESULTS: Forty-four eyes of 44 patients were included in the analysis. The IOP significantly decreased from a preoperative 27.0 mmHg to a postoperative 10.5 mmHg. The mean interval between the trabeculectomy and the date of post-operative SD-OCT measurement was 3.3 months. The global and sectoral BMO-MRW significantly increased after trabeculectomy, whereas the peripapillary retinal nerve fiber layer thickness did not show a difference between before and after the trabeculectomy. Younger age and a greater reduction in the IOP after the trabeculectomy were significantly associated with the increase in the BMO-MRW after trabeculectomy. CONCLUSIONS: The NRR thickness measured based on the BMO-MRW increased with decreasing IOP after trabeculectomy, and the increase in the BMO-MRW was associated with the young age of the patients and greater reduction in the IOP after trabeculectomy. Biomechanically, these suggest that the NRR comprises cells and substances that sensitively respond to changes in the IOP and age.

Repeatability of Spectral Domain Optical Coherence Tomography Measurements of Bruch's Membrane Opening-Minimum Rim Width in Epiretinal Membrane Patients with Peripapillary Involvement.

The Bruch's membrane opening-minimum rim width (BMO-MRW) is a recently introduced parameter of the neuroretinal rim. We analyzed the repeatability of spectral-domain optical coherence tomography (SD-OCT) measurements of BMO-MRW in epiretinal membrane (ERM) patients with peripapillary involvement, since the surface around the optic disc is distorted in such patients. BMO-MRW and retinal nerve fiber layer (RNFL) thickness measurements were performed using SD-OCT in prospectively enrolled ERM patients and age-matched healthy control individuals. After two consecutive measurements with a 5 min interval, repeatability was analyzed using the intraclass correlation coefficient (ICC), repeatability coefficient (RC), and coefficient of variation (CV). Fifty-two eyes of 52 ERM patients and 62 eyes of 62 healthy controls were included in the study. The ICCs of the mean BMO-MRW/RNFL thickness measurements were 0.999/0.985 in ERM eyes and 0.999/0.999 in normal eyes, respectively. The RC values of mean BMO-MRW/RNFL thickness measurements were 9.0/6.25 µm in ERM eyes and 4.61/0.92 µm in normal eyes, respectively. The CV values were 0.91% and 1.45% for BMO-MRW and RNFL thickness in ERM eyes, and 0.63% and 0.33% in normal eyes, respectively. In ERM eyes, the RC, CV of average BMO-MRW were 1.9 and 1.4 times greater than those of normal eyes, but 6.8 and 4.4 times greater for average RNFL thickness. BMO-MRW and RNFL thickness showed good repeatability in the diseased eyes with peripapillary involvement and healthy control eyes. Based on the ICC, RC, and CV values, the repeatability of BMO-MRW measurements in peripapillary membrane patients was better than that of RNFL thickness.

Bruch's membrane opening-minimum rim width: An alternative OCT biomarker study for multiple sclerosis.

PURPOSE: Bruch's membrane opening-minimum rim width (BMO-MRW) and RNFL measured using anatomic positioning system (APS-RNFL) are novel OCT methods and remained unexplored in MS patients.To investigate the novel parameters of spectral-domain OCT as an alternative biomarker in patients with multiple sclerosis (MS). METHODS: Retrospective cohort study; participants consisted of relapsing-remitting MS (RRMS) patients and healthy controls (HC). Eyes were classified according to the presence of MS and previous optic neuritis (ON). Measurements of standard peripapillary RNFL (S-RNFL), BMO-MRW, and APS-RNFL were performed. RESULT: A total of 244 eyes of 122 participants (MS-patients: 63, HC: 59) were included in the study. Fifty-one eyes had a history of previous ON. In almost all measured parameters, neuroretinal rim thicknesses were observed the thinnest in eyes with ON history between all subgroups. S-RNFL and APS-RNFL techniques showed the difference in neuroretinal rim thickness in all three subjects (ON+, ON-, and HC). However, BMO-MRW, on the other hand, could not distinguish between ON(-) patients and HC. The relationship between OCT parameters and EDSS were observed only in eyes with an ON history in all three techniques. A meaningful model with 78% accuracy was obtained by using only the OCT parameters as risk factors. In the ROC analysis, no parameters were found to have acceptable high sensitivity and specificity. BMO-MRW was statistically weaker in every aspect than other RNFL techniques. CONCLUSION: The novel APS-RNFL technique appears to be a bit more reliable alternative to S-RNFL technique to support therapeutic decision-making in MS. BMO-MRW has not been found as a successful alternative to S-RNFL.

Evaluation of Bruch's membrane opening-minimum rim width and retinal nerve fiber layer thickness in adults with anisometropic amblyopia.

PURPOSE: To investigate the relationship between Bruch's membrane opening-minimum rim width (BMO-MRW) and retinal nerve fiber layer thickness (RNFLT) in adult patients anisometropic amblyopia using spectral domain optical coherence tomography (SD-OCT). MATERIALS AND METHODS: In this cross-sectional, observational study, 43 anisometropic eyes with corresponding fellow eyes. BMO-MRW (shortest distance from BMO to the internal limiting membrane) and peripapillary RNFLT were obtained with Spectral Domain Optic Coherence Topography (SD-OCT). Global and six sectors values according to the legacy distribution of the SD-OCT (nasal [N], nasal superior [NS], temporal superior [TS], temporal [T], temporal inferior [TI], and nasal inferior [NI]) for both RNFLT and BMO-MRW were evaluated. RESULTS: Mean RNFLT and BMO-MRW measurements comparison showed no significance between anisometropia and fellow eyes. In correlation analyses ; although all sectors showed significant positive correlations; the global, TS and NI BMO-MRW sectors were significantly correlated with their corresponding RNFLT within both anisometropia and fellow eyes. In subgroup caparison analyses RNFLT and BMO-MRW showed no differences between amblyopia and fellow eyes. On subgroups correlation analyses, there were not a consistent correlation sectors between RNFLT and BMO-MRW. CONCLUSIONS: In the analysis of the BMO-MRW and RNFLT measurements obtained by SD-OCT in adult anisometropic amblyopia patients, both parameters were evaluated not significant on showing structural changes. In correlation analysis within amblyopic and fellow eye groups, while there was positive correlation on all sectors, statistically significant relationships were detected in global, NI, TS sectors for both BMO-MRW and RNFLT measurements.

Rate of Change in Bruch's Membrane Opening-Minimum Rim Width and Peripapillary RNFL in Early Normal Tension Glaucoma.

BACKGROUND: to investigate the rate of change (ROC) of Bruch's membrane opening minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness in early normal tension glaucoma (NTG) patients. METHODS: in this longitudinal cohort study, 115 subjects (115 eyes) diagnosed as early NTG (mean deviation > -6.0 dB) and who had completed more than five times of spectral-domain optical coherence tomography (OCT) tests with acceptable quality were included. Measurement of BMO-MRW and RNFL were performed at 3-month intervals by OCT. Linear mixed-effects model was employed to calculate the ROC in global region and six Garway-Heath sectors with adjusting age, sex, and BMO area. RESULTS: Average follow-up was 20.99 ± 6.99 months with OCT number of 7.54 ± 2.12. Baseline intraocular pressure was 14.72 ± 2.70 mmHg and MD was -2.73 ± 2.26 dB. ROC of global BMO-MRW was -2.06 ± 0.65 µm/yr and RNFL was -0.96 ± 0.16 µm/yr (p = 0.098). The most rapid ROC was in inferotemporal sector (BMO-MRW: -3.02 ± 0.88 µm/yr, RNFL: -1.96 ± 0.36 µm/yr) followed by superotemporal sector. CONCLUSION: The ROC of BMO-MRW, the new parameter along with that of RNFL should be considered in the management of early NTG. BMO-MRW may show visible reduction ROC better than RNFL to detect early progression in early NTG when visual field may not show significant change.

Structure-function relationship between Bruch's membrane opening-minimum rim width and perimetry in open-angle glaucoma subtypes.

PURPOSE: To seek the threshold value of Bruch's membrane opening-minimum rim width (BMO-MRW) where visual field (VF) damage occurs in open-angle glaucoma (OAG) and explore whether there are structural differences between primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG). METHODS: We recruited 83 healthy and 106 glaucoma (49 with POAG and 57 with NTG) subjects for this study. All subjects underwent optical coherence tomography (OCT), BMO-MRW scans, and Humphrey visual field (VF) analyzer examination. Global and sectoral BMO-MRW was correlated with the corresponding VF according to the Garway-Heath map. Using a broken-stick statistical model, the structure-function relationship of VF values and BMO-MRW, the tipping point where VF defects were associated with a reduction in BMO-MRW and the slopes above and below the tipping point were determined and compared between POAG and NTG. RESULTS: The tipping point of global BMO-MRW for VF impairment was 234.38 µm, 228.09 µm, and 249.68 µm in the OAG, POAG, and NTG groups, respectively. The slope below the tipping point was significantly steeper than the slope above it in all quadrants of each group (p < 0.001). The tipping point in NTG in the inferotemporal and nasal quadrants was smaller than that of POAG, especially in the inferotemporal quadrant. CONCLUSION: In OAG, BMO-MRW loss seems to occur before the onset of perimetric impairment. Compared with POAG, NTG appears to have more severe rim damage, especially in the inferotemporal quadrant at the onset of detectable VF defects.

Ganglion cell layer thinning in prodromal Alzheimer's disease defined by amyloid PET.

INTRODUCTION: The objective of this study was to investigate and compare optic nerve and retinal layers in eyes of patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) with paired control eyes using optical coherence tomography. METHODS: Sixty-three eyes of 34 subjects, 12 eyes with AD and 51 eyes with MCI, positive to 11C-labeled Pittsburgh Compound-B with positron emission tomography (11C-PiB PET/CT), and the same number of sex- and age-paired control eyes underwent optical coherence tomography scanning analyzing retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), Bruch's membrane opening-minimum rim width (BMO-MRW), inner plexiform layer (IPL), outer nuclear layer, and lamina cribrosa (LC). RESULTS: Compared with healthy controls, eyes of patients with positive 11C-PiB PET/CT showed a significant thinning of RNFL (P < .028) and GCL (P < .014). IPL and outer nuclear layer also showed significant thinning in two (P < .025) and one location (P < .010), respectively. No significant differences were found when optic nerve measurements BMO-MRW and LC were compared (P > .131 and P > .721, respectively). Temporal sector GCL, average RNFL, and temporal sector RNFL also exhibited significant thinning when MCI and control eyes were compared (P = .015, P = .005 and P = .050, respectively), and also the greatest area under the curve values (0.689, 0.647, and 0.659, respectively). GCL, IPL, and RNFL tend to be thinner in the AD group compared with healthy controls. DISCUSSION: Our study suggests that RNFL and GCL are useful for potential screening in the early diagnosis of AD. LC and BMO-MRW appear not to be affected by AD.

Characteristics of Patients Showing Discrepancy Between Bruch's Membrane Opening-Minimum Rim Width and Peripapillary Retinal Nerve Fiber Layer Thickness.

Background: To investigate clinical characteristics of patients showing discrepancy between Bruch's membrane opening minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness. Correlation with the visual field (VF) was also inspected. Methods: In this prospective, cross-sectional study, 106 eyes (106 subjects) showing normal BMO-MRW classification but abnormal RNFL classification were included. All patients underwent confocal scanning laser ophthalmoscopy, spectral-domain optical coherence tomography, and standard automated perimetry. Results: Clinical characteristics were as follows: mean age: 52.79 ± 14.75 years; spherical equivalent (SE), -2.52 ± 3.48 diopter (D); SE < -5.0 D, 34 (32.1%) eyes; large disc (>2.43 mm2), 40.6%; small disc (<1.63 mm2), 12.5%; VF index, 96.72 ± 9.58%; mean deviation, -1.74 ± 3.61 dB; ß-peripapillary atrophy (PPA), 96.2%; γ-PPA, 75.5%. Majority (86.1%) of these cases demonstrated normal (71.3%) or borderline (14.9%) on VF. Temporal and nasal RNFL showed significant differences among disc size subgroups (all p < 0.05). Nasal RNFL was significantly thicker in a large disc group than other subgroups. Temporal, superotemporal, inferotemporal, inferonasal RNFL, and superior RNFL peak location showed significant differences (all p < 0.05) among SE subgroups. Temporal RNFL was significantly thicker in the high myopia group than other subgroups. Conclusions: Temporalization of RNFL peaks in myopia and nasalization of RNFL peaks in large disc that display abnormal classifications might show normal classification of BMO-MRW. These findings of discrepancy between classifications should be considered in the diagnosis of early glaucoma.

Impact of ab-interno trabeculectomy on Bruch's membrane opening-based morphometry of the optic nerve head for glaucoma progression analysis.

PURPOSE: To analyze the longitudinal change in Bruch's membrane opening minimal rim width (BMO-MRW) and circumpapillary retinal nerve fiber layer (RNFL) thickness using spectral domain optical coherence tomography (SD-OCT) after glaucoma surgery via ab-interno trabeculectomy in adult glaucoma patients. METHODS: Retrospective audit of 65 eyes of 65 participants undergoing ab-interno trabeculectomy using electroablation of the trabecular meshwork. In 53 eyes, surgery was combined with phacoemulsification and posterior chamber lens implantation. Pre- and postoperative SD-OCT examinations of the optic nerve head (ONH), intraocular pressure (IOP), and visual field data were analyzed. Longitudinal change in morphometric SD-OCT parameters of the ONH was compared and correlated to change in IOP and visual field function. RESULTS: BMO-MRW increased significantly between baseline (BL) and follow-up (FU) within the first 6 months after surgery (BL = 167.85 ± 90 µm; FU = 175.59 ± 89 µm; p = 0.034). This increase correlated with postoperative lowering of IOP (rho = - 0.41; p = 0.016). Nine months after surgery (range, 7-12 months), there was no significant change in BMO-MRW (BL = 196.79 ± 79; FU = 196.47 ± 85 µm; p = 0.95), while in later follow-up, a decrease of BMO-MRW was found (BL = 175.18 ± 78; FU = 168.65 ± 72; p = 0.05). RNFL thickness was unchanged in early (p > 0.16) and significantly decreased in later follow-up (p = 0.009). Mean deviation (MD) of visual field function did not show a significant change before and after surgery. CONCLUSION: Electroablative ab-interno trabeculectomy leads to a significant transient mild increase in BMO-MRW. This increase was shown to correlate with IOP lowering. Significant loss of BMO-MRW in later follow-up may reflect insufficient IOP reduction by surgery. The parameters RNFL thickness and MD seem less impacted directly by surgery.

Optic nerve head morphology in primary open-angle glaucoma and nonarteritic anterior ischaemic optic neuropathy measured with spectral domain optical coherence tomography.

PURPOSE: Optic nerve head (ONH) parameters as well as circumpapillary retinal nerve fibre layer (RNFL) thickness values measured with two different spectral domain optical coherence tomography (SD-OCT) machines (Spectralis® and Cirrus® OCT) have been compared between two patient groups, primary open-angle glaucoma (POAG), nonarteritic anterior ischaemic optic neuropathy (NAION) and healthy controls. A comparison of the performance of the two OCT machines was made. METHODS: Twenty healthy controls, 20 POAG and 20 NAION patients with comparable visual field defects were included. Comparison between groups was made using anova and post hoc t-tests. To evaluate the diagnostic power of OCT to differentiate POAG from NAION, a stepwise linear regression analysis of the rim-RNFL correlation with adjusting covariates (optic disc area and age) was performed. Based on the regression formula, the area under the receiver operator characteristic (AUROC) was calculated. RESULTS: Both glaucoma and NAION patients showed significantly smaller global RNFL thickness values compared to healthy subjects in t-tests (p < 0.001), while only patients with glaucoma showed significantly smaller global ONH parameters for both devices compared to healthy subjects (p < 0.001). Correlation between global ONH parameters was highly statistically significant (r = 0.93), whereas in t-test a statistically significant difference between the two machines was detected (p < 0.001). Area under the receiver operator characteristic revealed a similarly good discrimination between glaucoma and NAION for Spectralis® (0.980) and Cirrus® OCT (0.945). CONCLUSION: NAION patients have similar RNFL thickness values as do glaucomatous eyes, whereas ONH parameters in NAION eyes were similar to those seen in healthy controls. This difference might help discriminating between these two different disease conditions in a chronic disease stadium, and in this regard, none of the two OCT machines performed better.

Bruch's membrane opening-minimum rim width and visual field loss in glaucoma: a broken stick analysis.

AIM: To determine the Bruch's membrane opening-minimum rim width (BMO-MRW) tipping point where corresponding visual field (VF) damages become detectable. METHODS: A total of 85 normal subjects and 83 glaucoma patients (one eye per participant) were recruited for the study. All of the patients had VF examinations and spectral-domain optical coherence tomography to measure the BMO-MRW. Total deviation values for 52 VF points were allocated to the corresponding sector according to the Garway-Heath distribution map. To evaluate the relationship between VF loss and BMO-MRW measurements, a "broken-stick" statistical model was used. The tipping point where the VF values started to sharply decrease as a function of BMO-MRW measurements was estimated and the slopes above and below this tipping point were compared. RESULTS: A 25.9% global BMO-MRW loss from normative value was required for the VF loss to be detectable. Sectorally, substantial BMO-MRW thinning in inferotemporal sector (33.1%) and relatively less BMO-MRW thinning in the superotemporal sector (8.9%) were necessary for the detection of the VF loss. Beyond the tipping point, the slopes were close to zero throughout all of the sectors and the VF loss was unrelated to the BMO-MRW loss. The VF loss was related to the BMO-MRW loss below the tipping point. The difference between the two slopes was statistically significant (P≤0.002). CONCLUSION: Substantial BMO-MRW loss appears to be necessary for VF loss to be detectable in patients with open angle glaucoma with standard achromatic perimetry.

Association of Bruch's membrane opening and optic disc morphology to axial length and visual field defects in eyes with primary open-angle glaucoma.

PURPOSE: To examine the morphology of Bruch's membrane opening (BMO), optic disc, and peripapillary atrophy (PPA) by scanning laser ophthalmoscopy (SLO) and spectral-domain optical coherence tomography (SD-OCT), and to determine their association with the axial length and visual field defects. METHODS: This was a cross-sectional study of 94 eyes of 56 subjects; 77 eyes were diagnosed with primary open-angle glaucoma and 17 eyes as normal. The margins of the optic disc were determined in the SLO images, and that of the BMO in the SD-OCT images. The ovality and area of the BMO and the optic disc were measured. The beta and gamma-PPA areas were also measured. The association of each parameter with the axial length and the mean deviation (MD) of the visual field tests was determined by generalized estimating equations (GEEs). RESULTS: The optic disc ovality was associated with the axial length and the MD (ß = -0.47, P = 7.6 × 10-4 and ß = 0.12, P = 0.040). The BMO ovality was not significantly associated with the axial length and the MD. The BMO area was associated with the axial length (ß = 0.30, P = 0.029). A larger BMO area was associated with a thinner BMO-based neuroretinal rim width (BMO-MRW) after adjustments for the MD (ß = -0.30, P = 2.1 × 10-4). The beta- and gamma-PPA areas were associated with the axial length (ß = 0.50, P = 7.4 × 10-5 and ß = 0.62, P = 4.2 × 10-6). CONCLUSIONS: The optic disc ovality was associated with both the axial length and MD, whereas BMO ovality was not. Attention should be paid to the influence of the axial length-related enlargement of the BMO.

Structure-function relationship comparison between retinal nerve fibre layer and Bruch's membrane opening-minimum rim width in glaucoma.

AIM: To evaluate and compare structural optical coherence tomography (OCT)-based parameters, such as Bruch's membrane opening-minimum rim width (BMO-MRW), and retinal nerve fiber layer (RNFL) thickness in glaucoma patients with visual field (VF) defects, and to correlate both to mean deviation (MD) values of obtained standard achromatic perimetry (SAP) examinations. METHODS: Patients with glaucoma and glaucomatous VF defects were enrolled in this prospective study and compared to age-matched healthy individuals. All study participants underwent a full ophthalmic examination and VF testing with SAP. Peripapillary RNFL thickness and BMO-MRW were acquired with SD-OCT. Correlation analyses between obtained global functional and global as well as sectorial structural parameters were calculated. RESULTS: A consecutive series of 30 glaucomatous right eyes of 30 patients were included and compared to 36 healthy right eyes of 36 individuals in the control group. Global MD of values correlated significantly with global RNFL (Pearson corr. coeff: 0.632, P=0.001) and global BMO-MRW (Pearson corr. coeff: 0.746, P<0.001) values in the glaucoma group. Global MD and sectorial RNFL or BMO-MRW values correlated less significantly. In the control group, MD values did not correlate with RNFL or BMO-MRW measurements. A subgroup analysis of myopic patients (>4 diopters) within the glaucoma group (n=6) revealed a tendency for higher correlations between MD and BMO-MRW than MD and RNFL measurements. CONCLUSION: In a clinical setting, RNFL thickness and BMO-MRW correlate similarly with global VF sensitivity in glaucoma patients with BMO-MRW showing higher correlations in myopic glaucoma patients.

Diagnostic Accuracies of Bruch Membrane Opening-minimum Rim Width and Retinal Nerve Fiber Layer Thickness in Glaucoma

PURPOSE: To compare the diagnostic capability of Bruch membrane opening-minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness for the detection of primary open angle glaucoma. METHODS: Spectral-domain optical coherence tomography (SD-OCT) with 24 radial and 1 peripapillary B-scans centered on the Bruch membrane opening (BMO) was performed. Two SD-OCT parameters were computed globally and sectorally: (1) BMO-MRW, the minimum distance between BMO and internal limiting membrane; and (2) peripapillary retinal nerve fiber layer (RNFL) thickness. The diagnostic performance of BMO-MRW and RNFL thickness were compared with receiver operating characteristic (ROC) analysis globally and sectorally. Areas under the ROC (AUC) were calculated and compared. RESULTS: One hundred fourteen eyes (52 healthy, 62 glaucomatous) of 114 participants were included. In global analyses, the performance of BMO-MRW was similar to that of RNFL thickness (AUC 0.95 [95% confidence interval {CI}, 0.91-0.99], and 0.95 [95% CI, 0.91-0.99], respectively, p=0.93). In sectoral analyses, the pair-wise comparison among the ROC curves showed no statistical difference for all sectors except for the superotemporal, superonasal, and nasal sectors, which had significantly larger AUCs in BMO-MRW compared to RNFL thickness (p=0.03, p<0.001, and p=0.03, respectively). The parameter with the largest AUC was the inferotemporal sector for both BMO-MRW and RNFL thickness (AUC 0.98 [95% CI, 0.96-1.00], and 0.98 [95% CI, 0.96-1.00], respectively, p=0.99). CONCLUSIONS: Global BMO-MRW performed as well as global RNFL thickness for detection of glaucoma. In superotemporal, superonasal and nasal sectors, regional BMO-MRW performed better than regional RNFL thickness.

Correlation between optic nerve head structural parameters and glaucomatous visual field indices.

We examined associations between optic nerve head structural parameters and glaucomatous visual field indices. The study population included patients with glaucomatous optic neuropathy who were evaluated at Aichi Medical University, Nagakute, Aichi, Japan, from October 2010 to January 2011. A total of 57 eyes from 33 patients were assessed. We measured visual field using a Humphrey field analyzer, peripapillary retinal nerve fiber layer thickness (RNFL-T), and Bruch's membrane opening-minimum rim width (BMO-MRW) using spectral domain optical coherence tomography, and rim area with referring three-dimensional photography. Spearman's rank correlation coefficients were calculated between the threshold of visual sensitivity or total deviation of visual field and the following five optic nerve head structural parameters: RNFL-T length, BMO-MRW length, rim area, and calculated RNFL-T and BMO-MRW volumes (each length multiplied by rim area). The Akaike information criterion was calculated to determine which structural parameter was the best predictor of each visual field index. Threshold of visual sensitivity had correlation coefficients of 0.23 with global sector of RNFL-T, 0.32 with BMO-MRW, 0.14 with rim area, 0.21 with RNFL-T volume, and 0.26 with BMO-MRW volume. The correlation coefficients for each parameter with total deviation of visual field were 0.22, 0.33, 0.28, 0.36, and 0.37, respectively. The Akaike information criterion of BMO-MRW showed the smallest values in analyses of both threshold of visual sensitivity and total deviation. The present results show that RNFL-T volume and BMO-MRW volume were more strongly correlated with total deviation than BMO-MRW, but BMO-MRW appeared to be the best predictor of the two glaucomatous visual field indices.