Topographic Measurement of the Subretinal Pigment Epithelium Space in Normal Aging and Age-Related Macular Degeneration Using High-Resolution OCT.

Purpose: A micrometer scale hyporeflective band within the retinal pigment epithelium basal lamina - Bruch's membrane complex (RPE-BL-BrM) was topographically measured in aging and age-related macular degeneration (AMD). Methods: In a prospective cross-sectional study, 90 normal eyes from 76 subjects (range = 23-90 years) and 53 dry AMD eyes from 47 subjects (range = 62-91 years) were enrolled. Isotropic volume raster scans over 6 mm × 6 mm (500 × 500 A-scans) were acquired using a high-resolution (2.7 µm axial resolution) spectral-domain optical coherence tomography (SD-OCT) prototype instrument. Six consecutive optical coherence tomography (OCT) volumes were computationally motion-corrected and fused to improve feature visibility. A boundary regression neural network was developed to measure hyporeflective band thickness. Topographic dependence was evaluated over a 6-mm-diameter Early Treatment Diabetic Retinopathy Study (ETDRS) grid. Results: The hyporeflective band thickness map (median of 4.3 µm and 7.8 µm in normal and AMD eyes, respectively) is thicker below and radially symmetric around the fovea. In normal eyes, age-associated differences occur within 0.7 to 2.3 mm from the foveal center (P < 0.05). In AMD eyes, the hyporeflective band is hypothesized to be basal laminar deposits (BLamDs) and is thicker within the 3-mm ETDRS circle (P < 0.0002) compared with normal eyes. The inner ring is the most sensitive location to detect age versus AMD-associated changes within the RPE-BL-BrM. AMD eyes with subretinal drusenoid deposits (SDDs) have a significantly thicker hyporeflective band (P < 0.001) than those without SDDs. Conclusions: The hyporeflective band is a quantifiable biomarker which differentiates AMD from aging. Longitudinal studies are warranted. The hyporeflective band may be a useful biomarker for risk stratification and disease progression.

Lamina Cribrosa Configurations in Highly Myopic and Non-Highly Myopic Eyes: The Beijing Eye Study.

Purpose: The purpose of this study was to examine characteristics of lamina cribrosa (LC) configuration in highly myopic (HM) eyes. Methods: Participants from the Beijing Eye Study 2011, free of optic nerve or retinal diseases, were randomly selected to examine LC depth (LCD) and LC tilt (LCT) using three-dimensional optical coherent tomography images of the optic nerve head (ONH). LCD and LCT were measured as the distance and angle between the LC plane with two reference planes, including the Bruch's membrane opening (BMO) plane and the peripapillary sclera (PPS) plane, respectively. Each parameter was measured in both horizontal and vertical B-scans. Results: The study included 685 individuals (685 eyes) aged 59.6 ± 7.7 years, including 72 HM eyes and 613 non-HM eyes. LCD measurements showed no significant differences between HM eyes and non-HM eyes in both horizontal (LCD-BMO = 421.83 ± 107.86 µm for HM eyes vs. 447.24 ± 104.94 µm for non-HM eyes, P = 0.18; and LCD-PPS = 406.39 ± 127.69 µm vs. 394.00 ± 101.64 µm, P = 1.00) and vertical directions (LCD-BMO = 435.78 ± 101.29 µm vs. 450.97 ± 106.54 µm, P = 0.70; and LCD-PPS = 401.62 ± 109.9 µm vs. 379.85 ± 110.35 µm, P = 0.35). However, the LCT was significantly more negative (tilted) in HM eyes than in non-HM eyes horizontally (LCT-BMO = -4.38 ± 5.94 degrees vs. -0.04 ± 5.86 degrees, P < 0.001; and LCT-PPS = -3.16 ± 5.23 degrees vs. -0.94 ± 4.71 degrees, P = 0.003), but not vertically (P = 1.00). Conclusions: Although LCD did not differ significantly between HM and non-HM eyes, LCT was more negative in HM eyes, suggesting that the temporal or inferior side of the LC was closer to the reference plane. These findings provide insights into morphological and structural changes in the LC and ONH between HM and non-HM eyes.

Bruch's Membrane Opening Changes in Eyes With Myopic Macular Degeneration: AIER-SERI Adult High Myopia Study.

Purpose: The purpose of this study was to assess the choroidal thickness and the Bruch's membrane opening size and their relationship to visual acuity in eyes with myopic macular degeneration (MMD). Methods: This was a population-based, cross-sectional study. Patients over the age of 30 years with high myopia (spherical equivalent ≤-5 diopters [D]) were recruited. The eyes were grouped according to the International Meta-Analysis for Pathologic Myopia (META-PM) classification based on fundus photographs and diffuse atrophy was subdivided into peripapillary diffuse choroidal atrophy (PDCA) or macular diffuse choroidal atrophy (MDCA). Swept-source optical coherence tomography imaging was performed and then the subfoveal choroidal thickness (SFCT) and Bruch's membrane opening diameter (BMOD) were measured. Results: Of the 470 study participants recruited, 373 patients (691 eyes), with a mean age of 42.8 ± 7.2 years, were eligible for the study and included in the analysis. There was no significant difference in SFCT between MDCA and patchy atrophy (M3) groups (P = 1.000), and the BMOD enlarged significantly from no myopic macular lesions to M3 (the P values of multiple comparison tests were all <0.005). Simple linear regression analysis showed that BMOD correlated positively with age (P < 0.001) and axial length (P < 0.001). Multiple linear regression analysis showed that best corrected visual acuity (BCVA) was significantly correlated with age (P = 0.041), axial length (P = 0.001), and BMOD (P = 0.017), but not with SFCT (P = 0.231). Conclusions: The significant variation of BMOD among MMD groups and the correlation between BMOD and BCVA in MMD eyes suggest that BMOD may be an imaging biomarker for monitoring MMD.

Comparing the morphology of optic nerve head and lamina cribrosa in full-term and preterm school-aged children.

OBJECTIVES: To evaluate the morphology of lamina cribrosa (LC) in preterm school-aged children. METHODS: A study of 120 eyes from 120 patients, including 42 full-term children (control group), 41 preterm children without retinopathy of prematurity (ROP), 16 children with ROP treated with intravitreal bevacizumab (IVB), and 21 children with ROP treated with laser. Five parameters of LC were measured by optical coherence tomography, including Bruch's membrane opening (BMO) diameter, minimum rim width (MRW), LC depth, prelaminar tissue (PLT) thickness, and LC curvature index (LCCI). RESULTS: The PLT thickness increased with age in full-term and preterm children (ß = 30.1, P = 0.003 and ß = 19.6, P < 0.001, respectively). LC depth and LCCI showed no differences between full-term and preterm children. Worse refractive errors in preterm children were associated with greater MRW and PLT thickness (ß = -17.1, P = 0.001 and ß = -5.7, P = 0.03, respectively). However, this relationship was not found in full-term children. Laser-treated children had greater MRW, PLT, temporal peripapillary retinal nerve fibre layer, and foveal thickness than full-term or other preterm children (all P < 0.05). CONCLUSIONS: Prematurity and ROP treatment may have an impact on the structural development of the LC. Refractive status plays a vital role in the LC structure of preterm children. This highlights the refractive errors of preterm children at school age that merit greater attention.

Bruchs Membrane Opening Area Measurement in Healthy Nepalese Eyes.

BACKGROUND: Bruch's membrane opening area is the circular area around the disc of Bruch's membrane, which is devoid of Bruch's membrane and can be assessed by capturing the retinal imaging system by Spectral-domain optical coherence tomography. BMOA can be a new landmark in analyzing the glaucomatous optic nerve head, myopic optic disc, optic neuropathy and uveitic disc edema. This is the first study from South Asia to evaluate the normal Bruch's membrane opening area among Nepalese eyes. METHODS: This hospital-based, cross-sectional, quantitative, observational study cross-sectional study was conducted in a tertiary eye care hospital in Nepal. Healthy immunocompetent Nepalese participants of both genders and different age groups were enrolled. The mean average Bruch's membrane opening area of each eyes, the difference in Bruch's membrane opening area between the two eyes and the gender of varying age groups were analyzed. RESULTS: Around 162 eyes (81 participants) were analyzed. The mean age was 56.69±17.5years. The mean average Bruch's membrane opening area of the right and left eye was 2.53±0.58 mm2 and 2.50 ±0.58 mm2. There was no significant difference in the Bruch's membrane opening area in either eye in both genders of any age group. CONCLUSION: The Bruch's membrane opening area does not differ significantly according to the laterality, gender and age group in Nepalese eyes.

PHENOTYPIC CHARACTERIZATION OF PREDICTORS FOR DEVELOPMENT AND PROGRESSION OF GEOGRAPHIC ATROPHY USING OPTICAL COHERENCE TOMOGRAPHY.

PURPOSE: To evaluate the impact of optical coherence tomography phenotypes preceding atrophy related to age-related macular degeneration on the progression of atrophic lesions. METHODS: In this observational retrospective cohort study, a total of 70 eyes of 60 consecutive patients with intermediate age-related macular degeneration with a minimum follow-up of 24 months were included. The atrophy was quantified using fundus autofluorescence, also considering the directionality of atrophy as centrifugal and centripetal progression rates. The main outcome measures were geographic atrophy (GA) progression rate (mm 2 /year) and square root transformation of GA (mm 2 /year). RESULTS: The best-fit model for GA (odds ratio: 1.81, P < 0.001) and square root transformation of GA (odds ratio: 1.36, P < 0.001) areas revealed that the main baseline predictor was the presence of a retinal pigment epithelium-basal lamina-Bruch membrane splitting. Large drusen at baseline appeared protective for the GA area lesion expansion over time (odds ratio: 0.52, P < 0.001) when considered with other confounders. CONCLUSION: A thin retinal pigment epithelium-basal lamina-Bruch membrane splitting without evidence of neovascularization on optical coherence tomography angiography likely represents an optical coherence tomography signature for late basal laminar deposits. Identifying this phenotype can help identify individuals with a higher risk of rapid progression and atrophy expansion.

Eight Years and Beyond Longitudinal Changes of Peripapillary Structures on OCT in Adult Myopia.

PURPOSE: To investigate the long-term changes of peripapillary structures detected by enhanced depth imaging of optical coherence tomography (OCT) in adult myopia. DESIGN: Observational case series. METHODS: Myopic participants who had undergone a full baseline ophthalmologic examination and had been followed up for a minimum of 8 years were included. Using enhanced depth imaging of OCT, scans around the optic disc in the Spectralis software Follow-up mode, which enabled capturing of the same positions, were performed in 65 eyes. The peripapillary parameters including the size of border tissue, Bruch membrane opening (BMO), peripapillary choroidal thickness, and the angle between peripapillary Bruch membrane (BM) and anterior sclera were manually delineated and measured. RESULTS: The axial length showed a significant elongation after a mean follow-up of 9.46 ± 0.92 years. The rates of changes were 0.015 ± 0.011 mm/y in the medium myopia group and 0.057 ± 0.039 mm/y in the high myopia group. At the last visit, the average border tissue length and BMO diameter were increased. The angle between peripapillary BM did not show significant change, while the angle between the peripapillary sclera showed a significant rise. On multivariate analysis, the border tissue elongation, BMO enlargement, and increased sclera angle were all associated with a change in axial length. The development of a BM defect and inward protrusion of sclera in the temporal peripapillary region was observed on 8 eyes (34.8%) in the high myopia group, along with an extreme thinning or disappearing of the peripapillary choroid. CONCLUSION: Marked longitudinal changes in peripapillary structures including border tissue, BM, choroid, and sclera could be observed in adult myopic eyes, which may impact the biomechanical environment around the optic nerve head.

Morphological differences of the neuroretinal rim between temporally tilted and non-tilted optic discs in healthy eyes.

This study aimed to compare morphological differences of the neuroretinal rim between the temporally tilted and non-tilted optic discs in healthy eyes. We prospectively enrolled participants aged 20-40 years with temporally tilted or non-tilted optic discs. The optic nerve head parameters were analyzed using spectral domain-optical coherence tomography. The angle between the Bruch's membrane opening (BMO) plane and BMO-minimum rim width (BMO-MRW) was termed "BMO-MRW angle". Peripapillary retinal nerve fiber layer thickness (pRNFLT) and BMO-based parameters were compared between the temporally tilted and non-tilted disc groups. As a result, 55 temporally tilted disc eyes and 38 non-tilted disc eyes were analyzed. Global pRNFLT, global BMO-MRW, and total BMO-minimum rim area (BMO-MRA) were similar between the two groups (p = 0.138, 0.161, and p = 0.410, respectively). In the sectoral analysis, temporally tilted disc group exhibited thicker BMO-MRW in the temporal sector (p = 0.032) and thinner in the nasal superior and nasal sectors (p = 0.025 and p = 0.002, respectively). Temporally tilted disc group showed larger BMO-MRA in the temporal, temporal superior, and temporal inferior sectors (p < 0.001, p < 0.001, and p < 0.016, respectively), alongside a higher BMO-MRW angle in the temporal sector and lower in the nasal superior and nasal sectors. In conclusion, the neuroretinal rim, represented by BMO-MRW and BMO-MRA, showed morphological differences between temporally tilted and non-tilted optic discs in healthy eyes. BMO-MRW and BMO-MRA showed temporalization in the same manner as pRNFLT in the temporally tilted disc eyes. The BMO-MRW angle showed that in temporally tilted disc eyes, optic nerve fibers met the BMO plane steeply in the nasal sector and gently in the temporal sector than in non-tilted disc eyes, suggesting potential stress region of optic nerve fibers in temporally tilted disc eyes.

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

OBJECTIVE: 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). DESIGN: Cross-sectional study. PARTICIPANTS: We included 162 glaucoma suspect or open-angle glaucoma eyes from 162 participants. METHODS: 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. MAIN OUTCOME MEASURES: 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. RESULTS: 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. CONCLUSIONS: 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. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Histopathology of myopic cobblestones.

PURPOSE: To search for the histological correlate of peripheral 'cobblestones' in highly myopic eyes. METHODS: The histomorphometric investigation included histologic sections of enucleated eyes of Caucasian patients. Using light microscopy, we measured the thickness of the retina, Bruch's membrane (BM) and choriocapillaris. RESULTS: The study included 50 eyes (mean age:60.6 ± 18.7 years;axial length:26.5 ± 3.8 mm), with cobblestone regions detected in 7 eyes. BM thickness and choriocapillaris thickness in the cobblestone region were thinner (1.1 ± 0.2 µm versus 2.4 ± 0.8 µm; p < 0.001 and 1.6 ± 0.5 µm versus 2.6 ± 1.9 µm; p = 0.02, respectively), and just outside of the cobblestone region they were thicker (3.3 ± 0.6 µm versus 2.4 ± 0.8 µm; p = 0.005 and 5.7 ± 1.6 µm versus 2.6 ± 1.9 µm; p = 0.002, respectively) than in corresponding regions of eyes without cobblestones. Within the group of eyes with cobblestones, BM thickness (1.1 ± 0.2 mm versus 3.3 ± 0.6 mm; p < 0.001), choriocapillaris thickness (1.6 ± 0.5 mm versus 5.7 ± 1.6 mm; p < 0.001) and choriocapillaris density (48±15 µm/300 µm versus 159 ± 66 µm/300 µm;PP=0.002) were significantly lower in the cobblestone region than just outside of the cobblestone region. The cobblestone regions were characterized by firm adhesion of disorganized retina with thinned BM, few retinal pigment epithelium (RPE) islands within cobblestone regions, and absence of regional scleral or overall choroidal thinning. BM was mono-layered within, and double-layered outside of cobblestone regions, with the inner layer missing within the cobblestone region (except for the RPE islands). CONCLUSIONS: Peripheral cobblestone regions in highly myopic eyes are characterized by marked BM thinning with absence of an inner BM layer, almost complete RPE absence, choriocapillaris thinning and firm connection of a disorganized retina to BM. These findings may help elucidating the process of axial elongation in myopic eyes.

Offset of openings in optic nerve head canal at level of Bruch's membrane, anterior sclera, and lamina cribrosa.

We compared the central retinal vascular trunk (CRVT) position, as a surrogate of lamina cribrosa (LC) offset, with the anterior scleral opening (ASCO) offset from the Bruch's membrane opening (BMO). Based on the BMO-centered radial scans, the BMO and ASCO margins were demarcated, and each center was determined as the center of the best-fitted ellipse for each margin. The ASCO/BMO offset was defined as the offset between each center. Angular deviations and the extent of ASCO and CRVT offsets from the BMO center were compared directly. Incomplete demarcation of ASCO was found in 20%, which was associated with a larger BMO area and a larger ASCO offset from the BMO. The angular deviation of ASCO offset was associated with that of CRVT offset and that of the longest externally oblique border. The ASCO offset was smaller than the CRVT offset, and, unlike the CRVT offset, it was rarely deviated to the inferior side. The complete ASCO margin might not be demarcatable when determined on BMO-centered radial scans in the presence of an offset. Also, the ASCO, which reflects only the superficial scleral layer, might not reflect the LC position, because the LC might be shifted further from the ASCO.

[Evaluation of choriocapillaris with high-speed spectral-domain optical coherence tomography angiography and image averaging]. / Otsenka statusa khoriokapillyarisa s pomoshch'yu vysokoskorostnoi spektral'noi opticheskoi kogerentnoi tomografii s funktsiei angiografii i tekhnologii usredneniya izobrazhenii.

PURPOSE: To study the capabilities of high-speed spectral-domain optical coherence tomography angiography (SD-OCTA) with image averaging in the evaluation of choriocapillaries in healthy individuals and patients with central serous chorioretinopathy (CSC). MATERIAL AND METHODS: All participants underwent OCTA examination on the SOLIX tomograph (Optovue, USA) using quadruplicate 3×3 mm scan with image averaging. Image analysis was performed in 9-µm custom slab with Phansalkar auto local threshold algorithm and calculation of flow voids larger than 5000 µm2 and 10 000 µm2. The optimal slab depth was determined in healthy eyes by consecutive analysis of the slabs with a 3-µm shift from zero position to 33 µm below Bruch's membrane. RESULTS: The study included 18 eyes of 18 healthy volunteers (40.4±6.0 years old) and 18 fellow eyes of 18 unilateral CSC patients (37.4±10.7 years old). The slab 12 µm below the Bruch's membrane showed the minimal number of flow voids (23.1±7.0 of >5000 µm2 voids per scan) and was chosen for further analysis. The number of flow voids of >5000 µm2 in healthy paired eyes of CSC patients was statistically significantly higher than in the eyes of healthy individuals (32.7±10.7 and 25.3±8.1 voids/scan, respectively; p=0.022). The number of flow voids of >10000 µm2 was also statistically significantly higher in CSC eyes compared to healthy eyes (5.6±3.3 and 3.5±1.9 voids/scan, respectively; p=0.045). There was no statistically significant difference in total area of the voids between the eyes of healthy individuals and CSC patients (96406.1±3924.5 µm2 and 95395.7 ± 3615.1 µm2, respectively; p=0.42). CONCLUSION: The optimal settings for choriocapillaris imaging on the SOLIX tomograph include 9-µm slab 9 to 18 µm below the Bruch's membrane. Using a 9-µm slab 12 µm below the Bruch's membrane, a substantial difference was found in choriocapillaris perfusion between eyes of healthy individuals and CSC patients.

Automatic segmentation of retinal layers in OCT images with intermediate age-related macular degeneration using U-Net and DexiNed.

Age-related macular degeneration (AMD) is an eye disease that can cause visual impairment and affects the elderly over 50 years of age. AMD is characterized by the presence of drusen, which causes changes in the physiological structure of the retinal pigment epithelium (RPE) and the boundaries of the Bruch's membrane layer (BM). Optical coherence tomography is one of the main exams for the detection and monitoring of AMD, which seeks changes through the evaluation of successive sectional cuts in the search for morphological changes caused by drusen. The use of CAD (Computer-Aided Detection) systems has contributed to increasing the chances of correct detection, assisting specialists in diagnosing and monitoring disease. Thus, the objective of this work is to present a method for the segmentation of the inner limiting membrane (ILM), retinal pigment epithelium, and Bruch's membrane in OCT images of healthy and Intermediate AMD patients. The method uses two deep neural networks, U-Net and DexiNed to perform the segmentation. The results were promising, reaching an average absolute error of 0.49 pixel for ILM, 0.57 for RPE, and 0.66 for BM.

A comparison of optic disc area measured by confocal scanning laser tomography versus Bruch's membrane opening area measured using optical coherence tomography.

BACKGROUND: Precise optic disc size measurements based on anatomically exact disc margins are fundamental for a correct assessment of glaucoma suspects. Computerized imaging techniques, such as confocal-scanning-laser-tomography (CSLT), which applies operator defined boundaries and optical-coherence-tomography (OCT), which incorporates an alternative detectable landmark (Bruch's-membrane-opening (BMO)), have simplified the planimetry of the optic disc and BMO-area, respectively. This study's objectives are to compare both modalities for area and to define a threshold for macro-BMO using BMO-OCT. METHODS: Retrospectively, patients that simultaneously received CSLT and BMO-OCT scans were included. Their images were correlated and agreement was determined using Bland-Altman-analysis. The diagnostic power of a macro-BMO threshold using OCT was derived after creating a receiver-operating-characteristics-curve using the well-established analogous CSLT threshold (2.43 mm2). RESULTS: Our study included 373 eyes with a median optic disc area by CSLT/ BMO-area by OCT of 2.56 mm2 and 2.19 mm2 respectively. The Bland-Altman-analysis revealed a systematic deviation with a diverging tendency with increasing area, which enabled the creation of the following mathematical relation: disc-area (CSLT)*0.73 + 0.3 = BMO-area (OCT). BMO-area of 2.19 mm2 showed the best diagnostic power for identifying macro-BMOs using OCT (sensitivity: 75%, specificity: 86%). CONCLUSIONS: Area measurements (CSLT optic disc area vs. BMO-area by OCT) showed a systematic deviation with a divergent tendency with increasing size. Our mathematical equation offers an estimated comparison of these anatomically diverse entities. Considering BMO-OCT´ anatomical accuracy, the 2.19 mm2 threshold may improve discernment between glaucoma suspects and norm variants.

The In Vivo Correlation between Retinal Pigment Epithelium Thickness and Quantitative Fundus Autofluorescence in a White Population.

PURPOSE: To investigate the influence of age on the thickness of the retinal pigment epithelium (RPE)/Bruch's membrane (BM) complex and the quantitative autofluorescence (qAF) and to study the possible correlation existing between these 2 parameters in a healthy White population. DESIGN: Cross-sectional, observational study. PARTICIPANTS: Healthy White volunteers aged 18 to 65 years. METHODS: All subjects underwent spectral domain OCT (SD-OCT) and qAF imaging with the Heidelberg HRA-Spectralis (Heidelberg Engineering, Heidelberg, Germany). Spectral domain OCT images were analyzed using the in-built graph-based automatic segmentation algorithm for single retinal layer identification to assess RPE/BM complex thickness in vivo. The thickness values of both inner and outer rings of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid, generated by the software using the "RPE" segmentation, were averaged to obtain a single RPE/BM complex thickness value in each eye. Quantitative autofluorescence images were also evaluated using a dedicated software. The qAF values of 8 subfields forming a ring centered onto the fovea were collected and averaged to obtain a single qAF value (qAF8) in each eye. The correlation among the RPE/BM complex thickness, the qAF value, and the age of the subjects was investigated. MAIN OUTCOME MEASURES: The in vivo correlation between RPE/BM complex thickness and qAF. RESULTS: A total of 105 eyes from 105 subjects (mean age, 42.1 ± 13.9 years; range, 18-65) were included in the analysis. The mean RPE/BM complex thickness significantly increased with age (r = 0.33, P = 0.0006). The values of qAF also positively increased with age (P < 0.0001). A significant correlation was found between qAF and RPE/BM complex thickness (r = 0.27, P = 0.004). After adjusting for age, iris color, and gender, the correlation remained significant only for subjects aged less than 40 years (P = 0.009). CONCLUSIONS: BM complex thickness was significantly co/BM complex thickness increased with age in a healthy White population. A similar increase was found for qAF values. After adjusting for age and iris color, qAF and RPE/BM complex thickness were still correlated in subjects aged less than 40 years. The RPE/BM complex thickness could reflect the lipofuscin/melanolipofuscin accumulation in normal subjects, adding great interest in RPE cell biology.

Visible light OCT improves imaging through a highly scattering retinal pigment epithelial wall.

Here we provide a counter-example to the conventional wisdom in biomedical optics that longer wavelengths aid deeper imaging in tissue. Specifically, we investigate visible light optical coherence tomography of Bruch's membrane (BM) in the non-pathologic eyes of humans and two mouse strains. Surprisingly, we find that shorter visible wavelengths improve the visualization of BM in pigmented eyes, where it is located behind a highly scattering layer of melanosomes in the retinal pigment epithelium (RPE). Monte Carlo simulations of radiative transport suggest that, while absorption and scattering are higher at shorter wavelengths, detected multiply scattered light from the RPE is preferentially attenuated relative to detected backscattered light from the BM.

Deep learning classification of early normal-tension glaucoma and glaucoma suspects using Bruch's membrane opening-minimum rim width and RNFL.

We aimed to classify early normal-tension glaucoma (NTG) and glaucoma suspect (GS) using Bruch's membrane opening-minimum rim width (BMO-MRW), peripapillary retinal nerve fiber layer (RNFL), and the color classification of RNFL based on a deep-learning model. Discriminating early-stage glaucoma and GS is challenging and a deep-learning model may be helpful to clinicians. NTG accounts for an average 77% of open-angle glaucoma in Asians. BMO-MRW is a new structural parameter that has advantages in assessing neuroretinal rim tissue more accurately than conventional parameters. A dataset consisted of 229 eyes out of 277 GS and 168 eyes of 285 patients with early NTG. A deep-learning algorithm was developed to discriminate between GS and early NTG using a training set, and its accuracy was validated in the testing dataset using the area under the curve (AUC) of the receiver operating characteristic curve (ROC). The deep neural network model (DNN) achieved highest diagnostic performance, with an AUC of 0.966 (95%confidence interval 0.929-1.000) in classifying either GS or early NTG, while AUCs of 0.927-0.947 were obtained by other machine-learning models. The performance of the DNN model considering all three OCT-based parameters was the highest (AUC 0.966) compared to the combinations of just two parameters. As a single parameter, BMO-MRW (0.959) performed better than RNFL alone (0.914).

Clinical manifestations of cuticular drusen in Korean patients.

Cuticular drusen show some similarities to and differences from soft drusen in age-related macular degeneration (AMD) and might thus be a unique AMD subtype. Previous studies on cuticular drusen were performed mainly in white ethnic groups, but AMD shows ethnic differences. We investigated clinical manifestations of cuticular drusen in Korean patients to evaluate possible ethnic differences. Clinical records of Korean patients with cuticular drusen were retrospectively reviewed. Fundus distribution pattern, imaging features, and presence of large drusen, drusenoid pigment epithelial detachment (PED), and macular complications, including geographic atrophy (GA), choroidal neovascularization (CNV), and acquired vitelliform lesion (AVL), were assessed via multimodal imaging in 162 eyes with cuticular drusen (n = 81 patients; 67 females; mean age: 66.6 ± 9.1 years). Diffuse distribution was found in 61.7% and peripapillary involvement in 75.3% of eyes. Large drusen, drusenoid PED, GA, CNV, and AVL were observed in 59.3%, 26.5%, 18.5%, 3.7%, and 1.2% of eyes, respectively. The macular complication prevalence was similar between patients ≤ 60 and those > 60 years old. In Korean patients, cuticular drusen were less frequently associated with macular complications than in white patients, and the proportion of macular complications differed significantly, with AVL representing an uncommon complication.

Effects of chronic methamphetamine abuse on the retinal nerve fiber layer, ganglion cell layer and Bruch's membrane opening minimum rim width.

BACKGROUND: Methamphetamine (Meth) is a highly addictive and hallucinogenic agent which is used as the second most common illicit drug globally. Meth could affect the retina and optic nerve by inducing the release of vasoconstrictive agents such as endothelin 1 and induction of severe oxidative stress with accumulation of reactive oxygen species. AIM: To evaluate the effects of chronic Meth abuse on the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL) and the Bruch's membrane opening minimum rim width (MRW). METHOD: In this case-control study, we recruited 55 Meth abusers and 49 healthy individuals with mean age of 44.63 ± 0.97 and 43.08 ± 0.91 years, respectively. RNFL thickness, GCL thickness and MRW were evaluated using optical coherence tomography. RESULTS: We found statistically significant decrease in RNFL, MRW thickness in Meth abusers (P: 0.002 and P: 0.006, respectively). We did not detect statistically significant difference regarding GCL thickness between the groups (P = 0.320). Our results showed a weak but statistically significant correlation of Meth dose increment and decrement of RNFL thickness ((P: 0.005, r = -0.193) and MRW (P: 0.013, r = -0.174). We found no correlation between duration of Meth consumption with RNFL and MRW thickness (P: 0.205, r= -0.124; P: 0.771, r= -0.029, respectively). CONCLUSION: We found a statistically significant adverse association in meth abusers with RNFL thickness and MRW. These two parameters were also statistically associated with the meth dose as measured by daily dose of Meth. Although we found a decrease in the GCL thickness, it did not reach statistical significance.

Bruch's Membrane Opening Minimum Rim Width Provides Objective Differentiation between Glaucoma and Nonglaucomatous Optic Neuropathies.

PURPOSE: A challenging clinical scenario is distinguishing between normal tension glaucoma (NTG) and non-glaucomatous optic neuropathies (NGON). The key to the assessment remains identifying the presence of optic nerve head cupping. Recent optical coherence tomography (OCT) measurements now allow objective assessment of cupping by minimum rim width at Bruch's membrane opening (MRW-BMO). This study assessed the hypothesis that the MRW-BMO measurement quantifies cupping and therefore can differentiate between NTG and NGON. DESIGN: Diagnostic evaluation with area under the curve. METHODS: Setting: multicenter tertiary hospitals and outpatient clinics. PATIENT POPULATION: 81 eyes of 81 patients were enrolled, 27 with NTG and 54 with NGON, including ischemic optic neuropathy, previous optic neuritis, and compressive and inherited optic neuropathies. All NGON patients with intraocular pressure >21 mm Hg, narrow drainage angles, or a family history of glaucoma were excluded. Observational procedure: optic disc OCT images were obtained of both the retinal nerve fiber layer thickness and the MRW-BMO. MAIN OUTCOME MEASUREMENTS: the utility of the MRW-BMO in differentiating GON from NGON was assessed using the area under the curve (AUC) estimated from a logistic regression model. RESULTS: The 5-fold cross-validated AUC for glaucoma versus nonglaucoma from logistic regression models using MRW-BMO values from all sectors was 0.95 (95% confidence interval: 0.86-1.00). CONCLUSIONS: The measurement of MRW-BMO effectively differentiates between NTG and NGON with a high level of sensitivity and specificity. Incorporating this measurement into routine glaucoma assessment may provide a robust method of assisting clinicians to improve diagnosis and therefore treatment of optic nerve diseases.