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Background/aims: Optical coherence tomography (OCT) is commonly used to diagnose and assess diabetic macular oedema (DME). Swept-source OCT (SS-OCT) promises improved imaging depth and more independence from media opacities. Heidelberg Spectralis full-depth imaging (FDI) combines details at different depths to one representation. The aim of this study was to determine the comparability of the imaging methods concerning DME ultrastructure., Methods: Two graders assessed the presence of typical DME phenomena in eyes with centre-involving DME on Topcon Atlantis SS-OCT and Heidelberg Spectralis FDI spectral-domain OCT (SD-OCT) B-scans. Retinal layer segmentation was corrected and choroidal layers were manually segmented. Graders measured cyst and subretinal fluid (SRF) diameters and counted hyper-reflective foci (HRF). Findings were recorded and statistically analysed., Results: Statistically significant systematic biases (Spectralis-Atlantis) were found for the HRF count (outside the central mm, -6.39, p=0.0338), chorioretinal thickness (central mm: -35.45 µm, p=0.00034), choroidal thickness (central mm: -60.97 µm, p=0.00004) and Sattler's layer thickness (-42.69 µm, p=0.0001). Intergrader agreement was excellent or very good for posterior vitreous detachment, vitreomacular attachment (central mm) and SRF presence in both devices. Manually delineated Sattler's layer thickness showed an intraclass correlation of 0.85 with FDI SD-OCT but 0.26 with SS-OCT (p=0.003)., Conclusion: Prominent aspects such as cysts in the outer nuclear layer and SRF can be identified with comparable confidence, while a significant systematic bias underlies chorioretinal, choroidal and Sattler's layer thickness and HRF count. Specialists should use the same device at every examination during longitudinal clinical consideration or cross-sectional evaluation of these ultrastructural biomarkers., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: To study macular morphology in amblyopic eyes using high-definition spectral domain optical coherence tomography (SD-OCT) and to compare the findings with fellow eyes., Methods: This was a prospective institutional study of patients ≥6 years of age with unilateral amblyopia. Enhanced high-definition single line macular scans of amblyopic eyes were obtained using SD-OCT and compared with fellow eyes. Scans were evaluated qualitatively for structural differences. Central foveal thickness was measured and areas of the different retinal layers were computed within 500 µm from the foveal centre nasally and temporally., Results: Forty-five patients with unilateral amblyopia were included: 25 with strabismic and 20 with anisometropic amblyopia with a mean age of 24.8 years. Qualitatively, the bulge in the inner segment/outer segment junction of the central fovea was noted to be attenuated or absent in 60% of amblyopic eyes compared with 29% of normal eyes, p=0.02. Also, amblyopic eyes demonstrated a shallow foveal pit compared with normal fellow eyes. Mean foveal thickness was significantly increased in amblyopic (228.56 µm) versus fellow eyes (221.72 µm), p=0.03. Upon exploring different retinal layers, the temporal inner nuclear layer area was increased (p=0.04) while the outer nuclear layer area was decreased (p=0.04) in amblyopic eyes compared with fellow eyes., Conclusions: Using enhanced high-definition SD-OCT, amblyopic eyes demonstrated qualitative and quantitative differences in macular features, possibly representing signs of immaturity compared with normal fellow eyes.

Background/aims: To evaluate the ultrastructural changes in the macula after successful repair of rhegmatogenous retinal detachment (RRD) using simultaneous spectral domain optical coherence tomography (sdOCT) and fundus autofluorescence (FAF) imaging and to perform functional correlations with microperimetry., Methods: Simultaneous sdOCT and FAF imaging were performed using a combined sdOCT-confocal scanning laser ophthalmoscope (cSLO) system. Microperimetry was performed in a subgroup of these patients., Results: 17 patients with macular-on RRD and 20 with macular-off RRD were recruited. sdOCT images revealed disruption of the external limiting membrane, inner segment/outer segment junction or the Verhoeff membrane in 16 eyes (43.2%). The presence of any or more of these disruptions was significantly associated with a poor postoperative best-corrected visual acuity (BCVA) (p<0.001). Patients with abnormal FAF were also associated with poor postoperative BCVA (p<0.001). However, there was a generally poor correspondence between the localisation of ultrastructural abnormalities as detected by sdOCT and FAF changes. Areas of decreased microperimetric sensitivity corresponded well with the ultrastructural changes and abnormal FAF., Conclusions: FAF changes may lag behind ultrastructural changes in the OCT, some of which may reverse with the passage of time. The present study demonstrates the ultrastructural changes assessed with simultaneous FAF and sdOCT and their relation with visual outcome.

In subretinal neovascularisation capillaries originating from the choriocapillaris must cross Bruch's membrane to reach the subretinal pigment epithelial space. Thus gaps in Bruch's membrane have to be formed before subretinal neovascularisation. Histological examination of eyes with subretinal neovascularisation or disciform scars has shown macrophages adjacent to thin areas and ruptures in Bruch's membrane. This has been interpreted as phagocytosis of Bruch's membrane. The purpose of this study was to investigate whether immune complex depositions can be detected in maculae with early stages of age-related macular degeneration and to explain the macrophage reaction before the disciform reaction. A series of 20 human maculae were examined by direct immunofluorescence light microscopy to detect the presence of immune complexes with antibodies directed against immunoglobulins, fibrinogen, and complement factors. Transmission electron microscopy on several maculae was performed to identify the macrophages. Macrophages were observed in close relation to the readily recognisable long spacing collagen, which suggested that long spacing collagen was selectively internalised by these cells. Definite immune complex depositions were not found in basal laminar deposits or drusen. Linear deposits of fibrinogen and complement were frequently found in the outer collagenous zone of Bruch's membrane. However, because of the absence of immunoglobulins, it seems unlikely that these non-specific deposits might cause chemoattraction of macrophages and play a role in the initial phase of the development of subretinal neovascularisation and disciform macular degeneration.

Clinical and pathological examination was performed on 378 eyes from 216 patients aged 43 to 97 years. This series represented eyes in which the fundi were normal or showed various manifestations of senile macular degeneration. The eyes were divided into six groups according to the histological appearance of a linear deposit at the base of the retinal pigment cells. Groups I and II were considered to represent normal ageing, Groups III and IV the progressive development of senile macular degeneration and Groups V and VI the end-results. Group I showed no basal linear deposit. Thickening and hyalinization of Bruch's membrane was noted as early as the fifth decade. Group II showed patchy development of the basal linear deposit in relation to thickened or basophilic segments of Bruch's membrane, or over intercapillary hyalinization extending to the level of the outer surface of the choriocapillaris. Almost all eyes in these two groups retained a normal fundus appearance but visual acuity declined with age even in the absence of other causes. In Group III the basal deposit formed a thin continuous layer associated with moderate degeneration of the retinal pigment epithelium. More than half the eyes had developed a clinical disturbance of pigmentation and in most vision was reduced. Group IV was characterized by thickening of the deposit and more pronounced disturbance of the pigment epithelium. Clinically most eyes showed coarse pigmentary changes and vision was in the order of 6/24. 14-3 per cent of eyes in this group showed early neovascularization from the choroid. In Group V the pigment epithelium disappeared to produce circumscribed areas of depigmentation. The basal linear deposit could be traced throughout the depigmented area in most eyes. Thin fibrovascular sheets were found beneath the pigment epithelium in 41-7 per cent of eyes. Group VI represented disciform degeneration. The basal linear deposit could often be demonstrated as a disrupted hyalinized layer incorporated into the scar. Disciform degeneration was an alternative end-result to geographical atrophy. In each group the clinical and histological findings may be modified by the presence of drusen or by atrophy of the choroid. The basal linear deposit consisted of banded fibres embedded in granular material lying between the plasma infoldings and the basement membrane of the retinal pigment epithelium. This deposit seems to be a manifestation of gradual failure of the pigment epithelium and proved to be the most suitable criterion by which to study the natural history of senile macular degeneration.