Novel Insights Based on the Anatomy of Henle Fiber Layer

Purpose: The purpose of this study was to identify a precise location of deep capillary plexus (DCP) injury in acute macular neuroretinopathy (AMN) lesions using multimodal imaging. Methods: En face structural optical coherence tomography (OCT) images were manually segmented to delineate outer retinal AMN lesions involving the ellipsoid zone and interdigitation zone. AMN lesion centroid was calculated, and image distortion was applied to correct for Henle fiber layer (HFL) length and orientation. The resulting image was registered with the corresponding en face OCT angiography (OCTA) image segmented at the DCP and structural OCT volume before grading for vascular and structural features, respectively. Results: Thirty-nine AMN lesions from 16 eyes (11 female patients, mean age 34 ± 4 years) were analyzed. After correcting for HFL anatomy, in 62% of AMN lesions, the centroid co-localized with a capillary vortex (pattern 1); flow defects were detected in 33% of lesions (pattern 2); and in 5% of lesions no specific pattern could be identified (pattern 3). The detection of a specific pattern increased after correcting the projection of AMN lesion for HFL anatomy (28% vs. 5%, P = 0.04). Outer nuclear layer thickness was lower in the centroid area in 10 (29%) AMN lesions from 6 patients, all corresponding to lesions fitting pattern 2 (r = 0.78, P < 0.001). Conclusions: AMN lesions might be a result of DCP impairment at the level of the capillary vortex or draining venule. In eyes with AMN, the location of outer retinal changes associated with DCP ischemia appears to be influenced by the length and orientation of HFL.publishersversionpublishe

Bacillary Layer Detachment : analyse en imagerie multimodale et preuves histologiques d’une nouvelle terminologie en tomographie par cohérence optique

Objectif : clarifier la corrélation histologique du décollement de la couche bacillaire (BALAD) par une revue de la littérature et une analyse de l'imagerie rétinienne. Méthodes : revue de la littérature des descriptions antérieures du BALAD. Une analyse des images rétiniennes a été effectuée pour soutenir les conclusions anatomiques.Résultats : un total de 164 patients uniques avec BALAD sur la tomographie par cohérence optique (OCT) a été identifié dans la littérature publiée. Vingt-deux étiologies sous-jacentes, toutes associées à une exsudation sous-rétinienne, ont été identifiées. Quarante et une terminologies d'OCT différentes ont été trouvées. La caractéristique remarquable du BALAD en OCT était une scission de la rétine externe au niveau de la myoïde des segments internes des photorécepteurs, créant une cavité intrarétinienne caractéristique. La résolution du BALAD était suivie par la restauration rapide de la zone ellipsoïde en OCT. L'histologie des yeux atteints de dégénérescence maculaire liée à l'âge suggère que les photorécepteurs peuvent perdre leur segment interne. De plus, le détachement de la couche des segments internes est un artefact post-mortem courant. Nous proposons que le phénomène de BALAD se produit lors d’une exsudation sous-rétinienne aiguë, lorsque les forces physiologiques favorisant l'attachement des segments externes des photorécepteurs à l’épithélium pigmentaire dépassent la force d’adhésion des myoïdes des segments internes.Conclusion : notre étude sert à définir la nomenclature du BALAD en OCT, en se basant sur les informations de réflectance spécifiques obtenues par l’OCT et les observations histologiques récemment publiées. Notre description de la chronologie du BALAD sur l’imagerie multimodale soulève des questions sur les mécanismes qui conduisent à la régénération spontanée des photorécepteurs, en particulier de leur segment interne

Long-Term Outcomes of Bacillary Layer Detachment in Neovascular Age-Related Macular Degeneration

Purpose: To evaluate the clinical characteristics, multimodal imaging features, and long-term treatment outcomes of eyes with neovascular age-related macular degeneration (nAMD) and bacillary layer detachment (BALAD) treated with intravitreal anti-VEGF therapy.Design: Retrospective, longitudinal, case series.Participants: Treatment-naive patients with nAMD (n = 30) showing BALAD on OCT and undergoing anti-VEGF therapy.Methods: Clinical records and multimodal imaging results of up to 4 years after diagnosis were reviewed.Main outcome measures: Best-corrected visual acuity (BCVA) values were compared over time. The cumulative risk of and risk factors for subretinal fibrosis were assessed using Cox regression analyses, and adjusted hazard ratio (aHR) was computed.Results: Thirty eyes of 30 patients were included. Macular neovascularization (MNV) subtypes were distributed as follows: type 1, 63%; type 2, 27%; mixed type 1 and 2, 3%; type 3, 3%; aneurysmal type 1, 3%. The BCVA significantly improved after anti-VEGF loading phase (Snellen equivalent, from 20 of 118 to 20 of 71, P = 0.03), but it returned to the baseline levels at 4 years (Snellen equivalent, 20 of 103, P = 0.6). The cumulative risk of subretinal fibrosis was 77% at 4 years. The risk factors associated with subretinal fibrosis included hemorrhagic BALAD (aHR, 2.02; 95% confidence interval [CI] 1.54-3.22; P Conclusions: BALAD was found in association with all types of MNV in patients with nAMD. Long-term observation revealed poor functional outcomes related to the high risk of subretinal fibrosis.</p

Quantitative assessment of choriocapillaris flow deficits and type 1 macular neovascularization growth in age-related macular degeneration

Abstract During the past 15 years, new treatment paradigms for neovascular age-related macular degeneration (nvAMD) have evolved due to the advent of intravitreal anti-vascular endothelial growth factor (VEGF) therapy and rapid advances in retinal imaging. Recent publications describe eyes with type 1 macular neovascularization (MNV) as showing more resistance to macular atrophy than eyes with other lesion types. We sought to explore whether the perfusion status of the native choriocapillaris (CC) surrounding type 1 MNV influences its pattern of growth. To evaluate this effect, we analyzed a case series of 22 eyes from 19 nvAMD patients with type 1 MNV exhibiting growth on swept-source optical coherence tomography angiography (SS-OCTA) over a minimum follow-up of 12 months. We observed an overall weak correlation between type 1 MNV growth and CC flow deficits (FDs) average size (τ = 0.17, 95% CI [− 0.20, 0.62]) and a moderate correlation with CC FD % (τ = 0.21, 95% CI [− 0.16, 0.68]). Type 1 MNV was located beneath the fovea in most of the eyes (86%) and median visual acuity was 20/35 Snellen equivalent. Our results support that type 1 MNV recapitulates areas of CC blood flow impairment while serving to preserve foveal function

BACILLARY LAYER DETACHMENT

To clarify the histologic basis of bacillary layer detachment (BALAD) through a review of current literature and an analysis of retinal imaging. Methods: We reviewed the literature for previous reports of BALAD. An analysis of retinal images was performed to support anatomic conclusions. Results: A total of 164 unique patients with BALAD on optical coherence tomography (OCT) were identified from the published literature. Twenty-two underlying etiologies, all associated with subretinal exudation, were identified. Forty-one different OCT terminologies were found. The defining OCT feature of BALAD was a split at the level of the photoreceptor inner segment myoid creating a distinctive intraretinal cavity. Resolution of BALAD was followed by a rapid restoration of the ellipsoid zone. Histology of age-related macular degeneration eyes suggests that individual photoreceptors can shed inner segments. Further, detachment of the entire layer of inner segments is a common postmortem artefact. We propose that BALAD occurs when outwardly directed forces promoting attachment of photoreceptor outer segments to the retinal pigment epithelium exceed the tensile strength of the photoreceptor inner segment myoid. Conclusion: Our review serves to strengthen the OCT nomenclature “bacillary layer detachment”, based on specific reflectance information obtained by OCT and previously published histologic observations