Membrane Opening Minimum Rim Width Research Articles

Sources of Discrepancy between Retinal Nerve Fiber Layer and Bruch’s Membrane Opening-Minimum Rim Width Thickness in Eyes with Glaucoma

Sources of Discrepancy between Retinal Nerve Fiber Layer and Bruch’s Membrane Opening-Minimum Rim Width Thickness in Eyes with Glaucoma

Diagnostic Accuracy of Optic Nerve Head and Macula OCT Parameters for Detecting Glaucoma in Eyes With and Without High Axial Myopia

PurposeTo characterize structural differences and assess the diagnostic accuracy of optic nerve head (ONH) and macula optical coherence tomography (OCT) parameters to detect glaucoma in eyes with and without high axial myopia. DesignCross-sectional study Methods368 glaucoma and 411 healthy eyes with no axial myopia, 393 glaucoma and 271 healthy eyes with mild axial myopia and 124 glaucoma and 85 healthy eyes with high axial myopia were included. Global and sectoral peripapillary retinal nerve fiber layer thickness (pRNFLT), Bruch's membrane opening minimum rim width (BMO-MRW), ganglion cell inner plexiform layer thickness (GCIPLT), and macula RNFLT (mRNFLT) were compared and the diagnostic accuracy for glaucoma detection was evaluated using adjusted area under the receiver operating characteristic curve (AUC). ResultsDiagnostic accuracy for ONH and macula parameters to detect glaucoma was generally high and differed by myopia group. For ONH parameters the diagnostic accuracy was highest for global (AUC=0.95) and inferotemporal (AUC=0.91) pRNFLT for high myopes and global BMO-MRW for non-myopes (AUC=1.0) and mild myopes (AUC=0.97). For macula parameters, the diagnostic accuracy was higher in high myopes with 6 of the 11 GCIPLT global/sectors having adjusted AUCs > 0.90 compared to non-high myopes with no AUCs > 0.90. In all myopia groups, mRNFLT had lower AUCs than GCIPLT. ConclusionsThe diagnostic accuracy for pRNFL and GCIPL was high for high axial myopic eyes and shows promise for glaucoma detection in high myopes. Further analysis is needed to determine whether the high diagnostic accuracy can be confirmed in other populations.

Susceptibility of optic nerve head in children with posture-related elevation of intraocular pressure

Background/AimsThis work aimed to investigate changes in optic nerve head (ONH) morphometry based on Bruch membrane opening in children with extensive nocturnal intraocular pressure (IOP) elevations.MethodsThe course of Bruch membrane opening-based optic nerve head (ONH) morphometry was analysed in thirty-two patients younger than 18 years with evaluable SD-OCT examinations of the ONH and nocturnal posture-dependent IOP elevation above 25 mmHg. Longitudinal changes in neuroretinal rim tissue, as measured by Bruch Membrane opening minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness, were assessed.ResultsOne year after the 24 h IOP measurement, global BMO-MRW (− 1.61 ± 16.8 µm, n.s.; p = 0.611) and RNFL (+ 0.64 ± 3.17 µm; n.s.; p = 0.292) measurements were not significantly different from the baseline. No significant BMO-MRW reduction (− 3.91 ± 24.3 µm; n.s. p = 0.458) or deviation in RNFL thickness (+ 1.10 ± 3.52 µm) was observed at the four-year follow-up. Absolute IOP values measured in the supine position did not correlate with changes in global BMO-MRW or RNFL thickness.ConclusionPosture-dependent IOP elevations do not seem to influence retinal nerve fibre layer thickness or Bruch membrane opening-based morphometric data in childhood.

Viral Anterior Uveitis: Differences in Retinal Vessel Area Density between the Affected and Non-Affected Eye Using Optical Coherence Tomography Angiography

ABSTRACT Purpose To investigate differences in the retinal vessel area density (VAD) on optical coherence tomography angiography (OCTA) between eyes with unilateral herpetic viral anterior uveitis (VAU) (herpes-simplex virus (HSV) and varicella-zoster virus (VZV)) and the non-affected fellow eye. Methods In this monocentric, observational, prospective case series we analyzed the VAD of the macula, optic disc, and peripapillary region in affected and non-affected eyes of 22 patients with HSV-positive and 22 patients with VZV-positive VAU using OCTA. We analyzed also the visual field mean deviation (MD), the retinal nerve fiber layer (RNFL) thickness, Bruch’s Membrane Opening-Minimum Rim Width (BMO-MRW), and ganglion cell layer (GCL) thickness on OCT and correlated the results with the different VADs. Results The macular VAD in the superficial vascular plexus (SVC) was significant lower in the affected compared to the non-affected eye for both viruses (HSV: 33.0% ± 3.3% vs. 34.7% ± 2.6%, p = 0.011; adjusted p = 0.040; VZV: 33.1% ± 3.2% vs. 34.3% ± 2.8%, p = 0.012; adjusted p = 0.050). Additionally, the VAD of the peripapillary SVC differed between the affected and non-affected eye for VZV-positive VAU (47.1% ± 6.2% vs. 50.5% ± 6.3%, p = 0.048, adjusted p = 0.100). For both HSV-positive and VZV-positive VAU, there were correlations between macular or peripapillary SVC VAD and BMO-MRW, GCL thickness, RNFL thickness or MD of the affected eye. Conclusion We observed vascular dysfunction characterized by decreased macular and peripapillary VAD in the superficial plexus on OCTA in eyes with HSV- and VZV-positive VAU compared to non-affected fellow eyes. These changes might be an early sign of glaucomatous damage or may be a direct consequence of the herpes viruses themselves.

Longitudinal Rates of Change in Structural Parameters of Optical Coherence Tomography in Primary Angle Closure Glaucoma following Laser Iridotomy along with Peripheral Iridoplasty.

This study aimed to investigate longitudinal rates of change (LRCs) of structural parameters from optical coherence tomography (OCT) in patients with primary angle closure glaucoma (PACG) after laser iridotomy (LI) along with laser peripheral iridoplasty (PI). Among 146 patients diagnosed with PACG, thirty-two subjects (32 eyes) who underwent LI plus PI and accomplished more than five times of reliable OCT tests were included in the current retrospective study. Retinal nerve fiber layer (RNFL) and Bruch's membrane opening-minimum rim width (BMO-MRW) were measured by spectral-domain OCT with three month interval. LRCs of global and six Garway-Heath sectors were investigated using the linear mixed-effects model which adjusted BMO area, sex, and age. Imaging of dual Scheimpflug analyzer was performed before and at 1 week after LI with PI and yearly thereafter. The mean follow-up period was 32.28 ± 13.34 months with a mean number of 10.18 ± 3.33 OCT images. Baseline characteristics are as follows: age, 63 ± 7.9 years; female, 62.5%; intraocular pressure(IOP), 15.48 ± 4.79 mmHg; anterior chamber depth, 2.09 ± 0.18 mm; and mean deviation, -7.97 ± 8.48 dB. Global LRC of BMO-MRW was 0.86 ± 1.34 μm/yr and RNFL was -0.64 ± 0.22 μm/yr. IOP decreased significantly to 13.06 ± 2.21 mmHg (p=0.001) while anterior chamber volume (p=0.011) and mean anterior chamber angle (p=0.022) increased significantly after LI along with PI compared to the baseline at the final visit. LRC of a new parameter, BMO-MRW, and LRC of RNFL were relatively low in patients with PACG, following LI along with PI. After widening of the anterior chamber angle and decrease of IOP due to LI plus PI, PACG might show stable structural prognosis assessed by OCT.

Accuracy of Bruch’s membrane opening minimum rim width and retinal nerve fiber layer thickness in glaucoma diagnosis depending on optic disc size

Background/aimThe aim of this paper is to compare retinal nerve fiber layer thickness (RNFL) and Bruch’s membrane opening-based minimum rim width (BMO-MRW) in terms of their performance in detecting early and moderate/advanced glaucoma using receiver operating characteristics (ROC) analysis and the classification using the 5th percentile as a cut-off.MethodsOne hundred eyes from 100 patients with early glaucoma (mean deviation (MD): < -5.0 dB) and 100 eyes from 100 patients with moderate/advanced glaucoma (MD: > -5.0 dB) were carefully matched to healthy controls based on optic disc size. Then, the dataset was divided, based on the 50th percentile of the measured Bruch’s membrane opening area (BMO-A), into small (BMO-A < 1.95 mm2) and large optic discs (BMO-A > 1.95 mm2). Finally, the discriminative performance of BMO-MRW and RNFL between glaucoma and controls using ROC analysis and the manufacturer’s classification based on the 5th percentile was analyzed.ResultsIn discriminating between glaucoma and matched healthy controls, global BMO-MRW and global RNFL thickness had comparable areas under the ROC curve for eyes with early glaucoma and both small BMO-As (ROC ± confidence interval [CI] 0.91 [0.87 to 0.95] and 0.88 [0.83 to 0.93]) and large BMO-As (0.86 [0.82 to 0.92] and 0.84 [0.79 to 0.90]), as well as in moderate/advanced glaucoma with small BMO-As (0.99 [0.98 to 1.00] and 0.97 [0.95 to 1.00]) and large BMO-As (0.94 [0.91 to 0.98] and 0.97 [0.94 to 1.00]). Using the calculated 5th percentile as a threshold value, the sensitivities for the detection of early and moderate/advanced glaucoma were comparable for BMO-MRW and RNFL in eyes with small optic discs (early glaucoma: fifty-two percent and 61%; moderate/advanced glaucoma: ninety-one percent and 92%). In eyes with large optic discs, the sensitivity of BMO-MRW was inferior to that of RNFL for both early (38% versus 51%) and moderate/advanced (80% versus 91%) glaucoma.ConclusionBased on an ROC analysis, the discriminative performance of BMO-MRW and RNFL between patients with early and moderate/advanced glaucoma and a healthy control group matched based on optic disc size is comparable in eyes with BMO-As smaller and larger 1.95 mm2. Using a classification based on the 5th percentile, as used in clinical practice, RNFL is shown to be superior to BMO-MRW regarding sensitivity in glaucoma detection with large optic discs. This study underscores the importance of RNFL imaging and measurement in the diagnostic evaluation of glaucoma, especially in cases of large optic discs.

Factors Affecting Post-Cataract OCT Parameters in Open-Angle and Angle-Closure Glaucoma Eyes: Optic Disc Head Analysis

Purpose: The aim of this study was to investigate whether there are differences in the effects of cataract surgery based on the type of glaucoma and changes in the retinal nerve fiber layer (RNFL) thickness and Bruch's membrane opening-minimum rim width (BMO-MRW) thickness around the optic nerve and macula in patients with glaucoma. Furthermore, the factors influencing these effects were explored.Methods: 68 patients with glaucoma were enrolled, and changes in RNFL thickness and BMO-MRW before and after cataract surgery were measured using SD-OCT. The patients were divided into angle-closure and open-angle glaucoma groups and values before and after cataract surgery were analyzed.Results: The male-female ratio was 26:42, with an average age of 71.72 years at the time of surgery. There were 35 eyes with open-angle glaucoma and 33 eyes with angle-closure glaucoma. After cataract surgery, both RNFL and BMO-MRW values significantly increased. In the angle-closure glaucoma group, preoperative visual acuity was significantly better and RNFL image Q was significantly higher before cataract surgery. In a multivariate linear regression analysis, the factor influencing the increase in RNFL thickness was found to be the preoperative RNFL thickness in both the overall open angle glaucoma group and the angle closure glaucoma group. In other words, patients with thinner RNFL thickness before cataract surgery showed an increase in RNFL thickness after the surgery. In the angle closure glaucoma group, it was observed that worse preoperative visual acuity was associated with an increase in RNFL thickness after surgery. Conversely, no factors affecting BMO-MRW thickness were identified.Conclusions: The factors influencing the increase in RNFL thickness after cataract surgery were the preoperative RNFL thickness in open angle glaucoma group and the preoperative visual acuity in the angle closure glaucoma group.

OCT Segmentation Errors with Bruch's Membrane Opening-Minimum Rim Width as Compared with Retinal Nerve Fiber Layer Thickness

To compare the magnitude and location of automated segmentation errors of the Bruch's membrane opening-minimum rim width (BMO-MRW) and retinal nerve fiber layer thickness (RNFLT). Cross-sectional study. We included 162 glaucoma suspect or open-angle glaucoma eyes from 162 participants. We used spectral-domain optic coherence tomography (Spectralis 870 nm, Heidelberg Engineering) to image the optic nerve with 24 radial optic nerve head B-scans and a 12-degree peripapillary circle scan, and exported the native "automated segmentation only" results for BMO-MRW and RNFLT. We also exported the results after "manual refinement" of the measurements. We calculated the absolute and proportional error globally and within the 12 30-degree sectors of the optic disc. We determined whether the glaucoma classifications were different between BMO-MRW and RNFLT as a result of manual and automatic segmentation. The absolute error mean was larger for BMO-MRW than for RNFLT (10.8 μm vs. 3.58 μm, P < 0.001). However, the proportional errors were similar (4.3% vs. 4.4%, P= 0.47). In a multivariable regression model, errors in BMO-MRW were not significantly associated with age, location, magnitude, or severity of glaucoma loss (all P ≥ 0.05). However, larger RNFLT errors were associated with the superior and inferior sector location, thicker nerve fiber layer, and worse visual field (all P < 0.05). Errors in BMO-MRW and RNFLT were not likely to occur in the same sector location (R2= 0.001; P= 0.15). With manual refinement, the glaucoma classification changed in 7.8% and 6.2% of eyes with BMO-MRW and RNFLT, respectively. Both BMO-MRW and RNFLT measurements included segmentation errors, which did not seem to have a common location, and may result in differences in glaucoma classification. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Deep learning visual field global index prediction with optical coherence tomography parameters in glaucoma patients

The aim of this study was to predict three visual filed (VF) global indexes, mean deviation (MD), pattern standard deviation (PSD), and visual field index (VFI), from optical coherence tomography (OCT) parameters including Bruch's Membrane Opening-Minimum Rim Width (BMO-MRW) and retinal nerve fiber layer (RNFL) based on a deep-learning model. Subjects consisted of 224 eyes with Glaucoma suspects (GS), 245 eyes with early NTG, 58 eyes with moderate stage of NTG, 36 eyes with PACG, 57 eyes with PEXG, and 99 eyes with POAG. A deep neural network (DNN) algorithm was developed to predict values of VF global indexes such as MD, VFI, and PSD. To evaluate performance of the model, mean absolute error (MAE) was determined. The MAE range of the DNN model on cross validation was 1.9–2.9 (dB) for MD, 1.6–2.0 (dB) for PSD, and 5.0 to 7.0 (%) for VFI. Ranges of Pearson’s correlation coefficients were 0.76–0.85, 0.74–0.82, and 0.70–0.81 for MD, PSD, and VFI, respectively. Our deep-learning model might be useful in the management of glaucoma for diagnosis and follow-up, especially in situations when immediate VF results are not available because VF test requires time and space with a subjective nature.

Comparing Diagnostic Accuracy of MRW and RNFL in Detection of Glaucoma

Purpose: To compare diagnostic accuracy of Bruch’s membrane opening minimum rim width (BMO-MRW) and Retinal Nerve Fibre Layer (RNFL) in detection of glaucoma taking cup to disc ratio as gold standard. Study Design: Descriptive observational. Place and Duration of Study: Liaquat National Hospital, Karachi from September 2017 to February 2018. Methods: Total 344 participants including healthy and glaucoma suspect (according to the cup disc ratio or high intra ocular pressure more than 21 mmHg) were included. They were evaluated to compare diagnostic accuracy of MRW and RNFL taking cup to disc ratio as gold standard. Spectral domain OCT was performed. Sensitivity, specificity, and diagnostic accuracy of MRW and RNFL were calculated keeping cup-disc finding as gold standard. Results: Mean Cup to Disk Ratio was 0.54 ± 0.10. Total 97.4% cases were diagnosed to have Glaucoma by Cup to Disk Ratio, 84.3% cases were diagnosed with Glaucoma by RNFL and 94.8% cases by MRW. By RNFL, 288 patients were true positive and 7 patients were true negative. Sensitivity, Specificity, and accuracy were 86.0%, 77.8%, and 85.7% respectively. The results showed that by MRW, 324 patients were true positive, and 7 patients were true negative. Sensitivity, Specificity, and accuracy were 96.7%, 77.8%, and 96.2% respectively. Conclusion: The sensitivity of RNFL for diagnosis of glaucoma is higher than MRW. While the specificity of both RNFL and MRW was similar.

Identification of Glaucoma in Diabetics Using the Laguna-ONhE Colourimetric Method and OCT Spectralis.

Previous retrospective results are evaluated prospectively and blinded. A total of 221 eyes previously classified as normal (G1), 279 as moderate risk of glaucoma (G2) and 217 as high risk (G3) according to the Globin Discriminant Function (GDF) Laguna-ONhE index were examined with OCT Spectralis- Results: In G1, the Bruch's Membrane Opening Minimum Rim Width (BMO-MRW) was 332 ± 55 microns; in G2, it was 252 ± 47 (p < 0.0001); and in G3, 231 ± 44 (p < 0.0001). In G1, the 1% and 5% percentiles were 233 and 248, respectively; in G2, they were lower in 28.80% and 42.29% of cases, respectively; and in G3, in 50.23% and 63.59% of cases, respectively. Most of the cases were normal-tension glaucomas. Laguna-ONhE indices showed a curvilinear correlation with BMO-MRW results. The Retinal Nerve Fibre Layer (RNFL) showed a poor relationship with BMO. Assuming G1 to be truly normal, BMO-MRW would have a Receiver operating characteristic (ROC) curve area of 0.901 for G2 and G3 and 0.651 for RNFL. A significant reduction in pixels corresponding to vessels was found in G2 and G3 vs. G1 (p < 0.0001). In some cases, these defects appear to be mainly glaucomatous, and in others, they are associated with diabetic microangiopathy. In normal tension glaucoma, RNFL defects may be less severe than those inside the nerve.

Comparison of glaucomatous from non-glaucomatous optic neuropathy using Bruch's membrane opening minimum rim width optical coherence tomography measurements.

To compare glaucomatous from non-glaucomatous optic atrophy using optical coherence tomography (OCT) based on the measurement values of Bruch's membrane opening minimum rim width (BMO-MRW), which is a difficult task otherwise due to their varied course of disease progression, treatment protocols, and systemic association to visual impairment. This study was conducted in 40 eyes, comprising 20 eyes with non-glaucomatous optic neuropathy (NGON) and 20 eyes with glaucomatous optic neuropathy (GON). All patients underwent a complete ophthalmic examination followed by an OCT optic disc scan to calculate the measurement of BMO-MRW. The 5-fold cross-validated area under the curve for GON versus NGON from logistic regression models was 0.95 (95% confidence interval [CI]: 0.86-1.00) using BMO-MRW values from all sectors. The results revealed that the measurements were significantly lesser in GON than in NGON patients. Hence, OCT-based BMO-MRW values could be used as an additional test to compare glaucomatous with non-glaucomatous optic neuropathy patients, especially in cases of high clinical suspicion.

Optical Coherence Tomography-Derived Measurements of the Optic Nerve Head Structure of Aboriginal and Torres Strait Islander Children.

This study demonstrated significant differences in optic nerve head characteristics in Aboriginal and Torres Strait Islander children compared with non-Indigenous children, which has implications for glaucoma risk and diagnosis in Aboriginal and Torres Strait Islander populations. The purpose of this study was to examine the optic nerve head (ONH) characteristics of visually normal Aboriginal and Torres Strait Islander children and non-Indigenous Australian children. Spectral domain optical coherence tomography imaging was performed on the right eye of 95 Aboriginal and Torres Strait Islander children and 149 non-Indigenous Australian children (5-18 years). Horizontal and vertical line scans, centered on the ONH, were analyzed to determine the dimensions of the ONH (Bruch membrane opening diameter), optic cup diameter, Bruch membrane opening minimum rim width, and the peripapillary retinal nerve fiber layer thickness. The vertical but not horizontal Bruch membrane opening diameter of Aboriginal and Torres Strait Islander children was significantly larger than non-Indigenous children (mean difference: 0.09mm, P = 0.001). The horizontal (mean difference: 0.12mm, P = 0.003) and vertical cup diameter (mean difference: 0.16mm, P < 0.001) were also significantly larger in Aboriginal and Torres Strait Islander children, as were the horizontal and vertical cup-to-disc ratios (both P < 0.01). Aboriginal and Torres Strait Islander children also had a significantly thinner Bruch membrane opening minimum rim width in the superior, nasal, and temporal meridians (all P < 0.001). Peripapillary retinal nerve fiber layer thickness did not differ between groups. Differences exist in the ONH structure between Aboriginal and Torres Strait Islander children and non-Indigenous children, which may have implications for the detection and monitoring of ocular disease in this population and highlights the need to extend this research to the adult population.

Optical coherence tomography findings in children of patients with Alzheimer-type dementia

BackgroundOcular imaging receives much attention as a source of potential biomarkers for dementia. This study aims to study structural changes in the retina and optic nerve in children of healthy and demented parents and to confirm the applicability of optic nerve tomography as a potential noninvasive marker for the early diagnosis of dementia.MethodsHealthy individuals with a parent diagnosed with Alzheimer’s disease (AD) and healthy controls with healthy parents were included in the study. Included individuals had undergone Montreal Cognitive Assessment Scale and Mini-Mental Test by a single neurologist physician to confirm not having dementia. All the subjects then underwent a complete ophthalmological examination, including refractive error and keratometry readings, best-corrected visual acuity measurement with a Snellen chart (converted to LogMAR), intraocular pressure (IOP) measurement, slit-lamp biomicroscopy, dilated fundus examination, axial length measurement and optical coherence tomography (OCT) for the parapapillary retinal nerve fiber layer (pRNFL), basal membrane opening—minimum rim width (BMO-MRW), and macular thickness analysis. Only the right eyes of the subjects were evaluated. OCT findings of these two groups were compared.ResultsThe temporosuperior sector the pRNFL thicknesses at all 3 circles (3.5, 4.1, and 4.5) were significantly thinner in the children of the dementia group than in healthy controls (p = 0.023, 0.039, and 0.016, respectively). For the remaining sectors, the thicknesses of the pRNFL were also thinner, however, the differences were not significant (p > 0.05 for all). BMO-MRW at all sectors, were not also different significantly between the groups (p > 0.05 for all). Parents’ dementia grade were found to be an important factor that the BMO-MRW at the temporal sector, got thinner with increasing grade (B = − 20.631, 95% CI − 42.121 to − 0.019, and p = 0.049).ConclusionWe believe that OCT can be used as a noninvasive biomarker in the preclinical period, when supported by more extensive studies in people whose parents have AD.

Differences in optic nerve head structure between acute angle-closure glaucoma and open-angle glaucoma

This study aimed to compare the optic nerve head (ONH) structure in acute angle-closure glaucoma (AACG) and open-angle glaucoma (OAG) to investigate the differences in glaucomatous damage. The AACG and OAG eyes were matched with regard to global retinal nerve fiber layer thickness (RNFLT). AACG eyes were divided into two subgroups based on the presence of ONH swelling at the onset of AACG. RNFLT, Bruch’s membrane opening-minimum rim width (BMO-MRW), and Bruch’s membrane opening-minimum rim area (BMO-MRA) were analyzed. Global RNFLT values were similar in AACG and OAG groups, but lower than in the healthy group (P < 0.001). The global BMO-MRW and total BMO-MRA were significantly higher in AACG than in OAG group (P < 0.001, respectively). AACG showed similar global BMO-MRW and total BMO-MRA, irrespective of the presence or absence of ONH swelling, while AACG with ONH swelling was associated with significantly thinner global RNFLT compared to AACG without ONH swelling (P < 0.006). The result of differences in ONH structure between the OAG and AACG, especially the AACG with ONH swelling at the onset of AACG, suggests that the mechanisms of optic nerve damage in the two diseases are different.

Update on the Utility of Optical Coherence Tomography in the Analysis of the Optic Nerve Head in Highly Myopic Eyes with and without Glaucoma

Glaucoma diagnosis in highly myopic subjects by optic nerve head (ONH) imaging is challenging as it is difficult to distinguish structural defects related to glaucoma from myopia-related defects in these subjects. Optical coherence tomography (OCT) has evolved to become a routine examination at present, providing key information in the assessment of glaucoma based on the study of the ONH. However, the correct segmentation and interpretation of the ONH data employing OCT is still a challenge in highly myopic patients. High-resolution OCT images can help qualitatively and quantitatively describe the structural characteristics and anatomical changes in highly myopic subjects with and without glaucoma. The ONH and peripapillary area can be analyzed to measure the myopic atrophic-related zone, the existence of intrachoroidal cavitation, staphyloma, and ONH pits by OCT. Similarly, the lamina cribosa observed in the OCT images may reveal anatomical changes that justify visual defects. Several quantitative parameters of the ONH obtained from OCT images were proposed to predict the progression of visual defects in glaucoma subjects. Additionally, OCT images help identify factors that may negatively influence the measurement of the retinal nerve fiber layer (RNFL) and provide better analysis using new parameters, such as Bruch's Membrane Opening-Minimum Rim Width, which serves as an alternative to RNFL measurements in highly myopic subjects due to its superior diagnostic ability.

Retinal Nerve Fiber Layer Thickness/Minimum Rim Width Ratio Differentiates Glaucoma from Other Optic Neuropathies.

Global peripapillary retinal nerve fiber layer thickness/Bruch membrane opening- minimum rim width ratio is an objective and effective parameter to separate glaucomatous optic neuropathies (GONs) from nonglaucomatous optic neuropathies (NGONs). This study was undertaken to evaluate the diagnostic capability of the peripapillary retinal nerve fiber layer (pRNFL)/ Bruch membrane opening-minimum rim width (BMO-MRW) ratio to differentiate glaucomatous optic neuropathies (GONs) from nonglaucomatous optic neuropathies (NGONs). This retrospective study included patients with an optic neuropathy (ON), visual loss for>6 months and a confirmed single etiology. pRNFL thickness and BMO-MRW were measured with spectral-domain OCT (Spectralis®, Heidelberg Engineering, Heidelberg, Germany). The diagnostic accuracies of pRNFL, BMO-MRW and the global pRNFL/BMO-MRW ratio were evaluated with the areas under receiver operating characteristics curves (AUROCs). One eye each from 171 patients was investigated: 50 primary open-angle glaucomas, 15 normal pressure glaucomas, 50 optic neuritises, 15 nonarteritic anterior ischemic ONs, 24 compressive ONs, 10 dominant optic atrophies and 7 nutritional ONs. The global pRNFL/BMO-MRW ratio had the highest AUROC [0.97 vs. 0.92; P =0.01]. It was able to distinguish between GONs and NGONs with a cut-off value of 0.34. Increased mean deviation of the visual field-defect severity was associated with a higher ratio for GONs and a lower ratio for NGONs. Compared to NGONs and for the same degree of pRNFL thinning, lower BMO- MRW was found to be a specific marker of glaucoma, reflecting the neuroglial architecture changes within the optic nerve head typical of glaucoma and supporting fundamental pathophysiological differences.

Effect of Conventional Cataract Surgery and Femtosecond Laser-Assisted Cataract Surgery on Bruch's Membrane Opening-Minimum Rim Width, Retinal Nerve Fiber Layer, and Macular Thickness.

To evaluate the effect of conventional cataract surgery (CCS) and femtosecond laser-assisted cataract surgery (FLACS) on Bruch's membrane opening-minimum rim width (BMO-MRW), peripapillary retinal nerve fiber layer thickness (RNFL), and macular thickness (MT) using spectral-domain optical coherence tomography (SD-OCT). BMO-MRW, RNFL, and MT were measured using SD-OCT preoperatively, 1 month and 6 months after surgery in both CCS and FLACS groups. Differences between preoperative and postoperative values were evaluated in both groups. The postoperative changes were evaluated in each group and compared between groups. A total of 146 eyes of 146 patients were included in this study, 65 underwent CCS, and 81 underwent FLACS. One month after surgery, there was an increase (in microns) of 20.93 in BMO-MRW, 4.26 in RNFL, and 7.85 in MT in CCS group (P < 0.001), and 17.7, 3.73, and 5.65, respectively, in FLACS group (P < 0.001). Six months after surgery, there was an increase of 12.53 in BMO-MRW, 1.42 in RNFL, and 4.72 in MT in CCS group (P < 0.001), and 13.7, 1.88, and 4.14, respectively, in FLACS group (P < 0.001). The postoperative changes in CCS group were similar to those in FLACS group. CCS as well as FLACS result in a slight increase in BMO-MRW, RNFL, and MT values one month and six months after surgery. Neither CCS nor FLACS lead to a deterioration in the parameters that define the structure of the optic nerve head and the macula. These results suggest that FLACS is as safe as CCS regarding the optic nerve head and the macula in normal eyes.

Discovery of Clinical Manifestations in Spontaneous Glaucoma Suspect Nonhuman Primates

Introduction: The primary aim of this study was to assess the longitudinal changes in retinal nerve fiber layer (RNFL) thickness and relative ONH parameters using spectral-domain optical coherence tomography (SD-OCT) in the living eyes of nonhuman primates with spontaneous glaucoma. Methods: Totally 9 macaque subjects underwent a standard fundus photo and OCT examination, including 3 adult monkeys with stable elevated intraocular pressure (IOP) as the glaucoma suspect group and 6 normal IOP monkeys as the control group. Each eye of primates with IOP measurement was repeated three times. OCT measurements recorded RNFL, Bruch’s membrane opening (BMO) minimum rim width (MRW). The follow-up scan of glaucomatous subjects was undergone in 10 months. Results: The mean ages of glaucoma and healthy subjects are 19.33 ± 0.33 and 20.5 ± 1.46 years. Elevated IOP was achieved in three nonhuman primate eyes with an average increase of 10 mm Hg over the study period. Elevated IOP was associated with decreased RNFL thickness in all the regions and decreased RNFL phase retardation in the superior and inferior regions. When averaged over the entire retinal area, only the whole RNFL and temporal regions showed a significant decrease. The mean IPL thicknesses are 87.17 ± 2.15 μm in glaucomatous and 93.33 ± 1.51 μm in healthy eyes (p = 0.03). Lamina cribrosa parameters are measured from the OCT images and showed significant differences between glaucoma primates and normal primates. Conclusions: Of the measured parameters, decreased RNFL and MRW were correlated with glaucomatous damage. Natural glaucoma primate can be a natural glaucoma model which is closer to glaucoma in humans.

Analysis of retinal nerve layers in idiopathic, LRRK2-associated Parkinson's disease and unaffected carriers of G2019S mutation

IntroductionIn both prodromal and early symptomatic stages of idiopathic PD (iPD) peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell layer (mGCL) thinning have been identified. Here we assessed whether these alterations can also be detected in symptomatic and presymptomatic stages of LRRK2-PD. Methods218 eyes belonging to 20 iPD, 19 LRRK2-PD (L2PD), 24 LRRK2 non-manifesting carriers (L2NMC), and 46 controls (HCs). pRNFL, mGCL thickness (squares), and Bruch's membrane opening minimum rim width were evaluated by SD-OCT. In L2NMC, 123I-ioflupane SPECT (DaT-SPECT) with semi-quantitative analysis was carried out. ResultsCompared to HCs, iPD patients showed significant thinning of the temporal (BMO-MRW and pRNFL), superior-temporal (BMO-MRW), inferior-temporal (BMO-MRW), superior-nasal (BMO-MRW) and central sectors (BMO-MRW) (p < 0.05), as well as in five mGCL sectors (p < 0.05). No significant differences were found between the L2PD or L2NMC and HCs. BMO-MRW thickness in its temporal-superior, superior-nasal and middle sectors was influenced by disease duration (p < 0.05) and mGCL thickness in sectors TS1, TS2, TS3, NS1 and NS3 was influenced by UPDRSIII and age (p < 0.05). ConclusionLRRK2-PD is distinguished from iPD by absent or less retinal nerve involvement, both in clinical and preclinical stages.