Hyperreflective Band Research Articles

Acute Macular Neuro-retinopathy: a Rare Retinal Disorder, Presenting as Paracentral Scotoma

Acute Macular Neuro-retinopathy (AMN) is a rare clinical entity. We present a case of 26 years old male who presented with one-week old history of sudden onset of decrease vision in left eye associated with paracentral scotomas. Dilated fundus examination of the left eye showed multiple reddish brownish petalloid para-foveal lesions with apex pointing toward the fovea. OCT showed hyper-reflective bands in the Outer Nuclear Layer and Outer Plexiform Layer along with disruption of ellipsoid zones. Amsler grid drawn by the patient and the visual field showed scotoma corresponding to the macular lesion. The cause turned out to be undiagnosed essential hypertension. Purpose of presenting this case is that High Definition Optical coherence tomography (SD-OCT) makes diagnosis of some rare conditions easy and fast for an ophthalmologist, that might be misdiagnosed or missed with conventional OCT and FFA imaging test.
 Key Words: Acute Macular Neuro-retinopathy, Spectral Domain Optical Coherence Tomography, Paracentral Scotoma.

Visible Light Optical Coherence Tomography (OCT) Quantifies Subcellular Contributions to Outer Retinal Band 4.

PurposeTo use visible light optical coherence tomography (OCT) to investigate subcellular reflectivity contributions to the outermost (4th) of the retinal hyperreflective bands visualized by current clinical near-infrared (NIR) OCT.MethodsVisible light OCT, with 1.0 µm axial resolution, was performed in 28 eyes of 19 human subjects (21–57 years old) without history of ocular pathology. Two foveal and three extrafoveal hyperreflective zones were consistently depicted within band 4 in all eyes. The two outermost hyperreflective bands, occasionally visualized by NIR OCT, were presumed to be the retinal pigment epithelium (RPE) and Bruch's membrane (BM). RPE thickness, BM thickness, and RPE interior reflectivity were quantified topographically across the macula.ResultsA method for correcting RPE multiple scattering tails was found to both improve the Gaussian goodness-of-fit for the BM intensity profile and reduce the coefficient of variation of BM thickness in vivo. No major topographical differences in macular BM thickness were noted. RPE thickness decreased with increasing eccentricity. Visible light OCT signal intensity in the RPE was weighted to the apical side and attenuated more across the RPE in the fovea than peripherally.ConclusionsMorphometry of the presumed RPE and BM bands is consistent with known anatomy. Weighting of RPE reflectivity toward the apical side suggests that melanosomes are the predominant contributors to RPE backscattering and signal attenuation in young eyes.Translational RelevanceBy enabling morphometric analysis of the RPE and BM, visible light OCT deciphers the main reflectivity contributions to outer retinal band 4, commonly visualized by commercial OCT systems.

Paracentral acute middle maculopathy after uneventful ocular surgery with local anaesthetic blocks.

To describe the role of local anaesthetic blocks as a potential cause of paracentral acute middle maculopathy (PAMM) after uneventful ocular surgery. Retrospective, observational, international, multicentre case series. Nine cases of PAMM with associated visual loss following uneventful ocular surgery with local anaesthetic blocks were observed in a 9-year period (2011-2020). Demographic, ocular and systemic data, anaesthetic data and surgical details were collected. Visual acuity (VA), fundus photography, fluorescein angiography, optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images were reviewed. All nine cases were associated with decreased VA at 24 h postoperative check (ranging from hand movement to 20/200). A hyperreflective band within the middle retinal layers was observed in the structural OCT in the acute phase, evolving to thinning and atrophy of the inner retinal layers in sequential follow-up scans performed. Fluorescein angiography showed delayed perfusion in early arterial phase with normal perfusion in late venous phases. OCTA showed decreased perfusion in the deep capillary plexus. Visual recovery was variable between cases during follow-up (ranging from count fingers to 20/20). A combination of a vasoconstrictive effect of the anaesthetic agent, an intraocular pressure spike and a mechanical effect of the volume of anaesthetic injected may result in decreased retinal artery perfusion and be evidenced as PAMM in OCT scans. PAMM may present as a potential complication of local anaesthetic blocks in cases of unexpected visual loss after uneventful ocular surgery.

Morphological features and prognostic significance of multilayered pigment epithelium detachment in age-related macular degeneration

AimsTo investigate the structure of multilayered pigment epithelial detachment (m-PED) in neovascular age-related macular degeneration, and its association with visual prognosis and the progression of fibrotic scars at 12 months.MethodsWe...

Optical coherence tomography analyses based segmentation and relative intensity evaluation of outer retinal layers in patients affected with X-linked juvenile retinoschisis.

We aim to provide a description of the optical coherence tomography findings in the outer macula hyperreflective bands of our patients with X-linked juvenile retinoschisis. Also to categorize these changes and to quantitatively and qualitatively correlate their reflectivity levels with visual function. We manually segmented the borders, and depicted relative intensity of the inner segment ellipsoid band, and quantified the volume of edema. The average relative intensity of the ellipsoid zone, ISe band, for the control subject was 14.864, our patient's, with the mild disease was, 28.238 and 34.943 in OD and OS, respectively, and for the patient with severe disease was, 44.442 and 40.154 for OD and OS respectively. Thresholding showed a significant difference in edema volume between mild disease (~20%), and severe form (~50%). Relative intensity analyses are indicative of homogeneity variability. High standard deviation value illustrates the high dispersion of data values and is a safe marker of ellipsoid zone homogeneity. Data suggested that both anatomic and functional characteristic of outer macula hyperreflective bands were notably associated with the pathogenesis cascade in the photoreceptor cells. External limiting membrane line disruption is initiated by the volume of macular edema and followed by disorganization of the three lines in a stepwise pattern, first at the ellipsoid zone, followed by the cone outer segment tips zone and finally at the External limiting membrane.

Association of Acute Macular Neuroretinopathy or Paracentral Acute Middle Maculopathy with Sickle Cell Disease

To investigate the structural and microvascular changes in the retina and choriocapillaris in patients with sickle cell disease (SCD) demonstrating acute vision loss and acute macular neuroretinopathy (AMN) or paracentral acute middle maculopathy (PAMM) using multimodal imaging including OCT and OCT angiography (OCTA). Retrospective case series. Four hemoglobin SS (HbSS) or hemoglobin SC (HbSC) patients who demonstrated vision loss attributed to AMN (n= 2) or PAMM (n= 2). Clinical characteristics including best-corrected visual acuity and multimodal imaging features from fundus photography, fluorescein angiography, OCT, and OCTA were analyzed. Longitudinal changes in the structure and microvasculature of the retina and choriocapillaris were examined. In 2 patients with AMN, characteristic hyperreflective changes were observed in the outer nuclear layer with involvement of the ellipsoid and interdigitation zones. In 1 patient, the lesion was located in the foveal avascular zone, and only flow deficits in the choriocapillaris were noted. In the second patient, no flow loss was observed in the superficial capillary plexus (SCP) corresponding to the lesion, but flow loss was seen in the deep capillary plexus (DCP) and choriocapillaris. At the respective 1-year and 4-month follow-up examinations, the hyperreflectivities improved with no ensuing retinal atrophy. Deep capillary plexus and choriocapillaris flow also improved. Of the 2 patients with PAMM, 1 had PAMM in association with branch retinal arteriolar occlusions. In both patients, a hyperreflective band involving the inner plexiform, inner nuclear, and outer plexiform layers was seen in or adjacent to areas of prior macular thinning. These areas corresponded to flow deficits in both the SCP and DCP. At the respective 1-month and 1-year follow-up examinations, the hyperreflective band improved with ensuing atrophy of the middle retinal layers. OCT angiography demonstrated worsening of flow deficits in the corresponding SCP and DCP. To the best of our knowledge, this is the first report of AMN and the largest case series of AMN or PAMM in SCD to date. Paracentral acute middle maculopathy may precede macular thinning commonly observed in SCD. OCT angiography is a useful tool to demonstrate associated microvascular changes in AMN and PAMM in SCD.

Retinal imaging study diagnoses in\xa0COVID-19: a case report

BackgroundHyperreflective lesions at the level of ganglion cell (GCL) and inner plexiform retinal layers (IPL) by optical coherence tomography (OCT) and cotton wool spots in the examination of the eye fundus have recently been described as findings in patients with COVID-19 infection.Case reportWe report the case of a 42-year-old healthy Caucasian male anesthetist who had treated COVID-19 patients during the previous 5 weeks and suddenly presented with a temporal relative scotoma in his left eye. Best-corrected visual acuity was 20/20 for the left eye, and no discromatopsy or afferent pupillary defect was present. Visual field test was performed, with no significant findings associated with the focal loss of sensitivity described by the patient. The anterior segment was unremarkable on slit lamp examination in both eyes. Fundus examination of the left eye showed no significant findings. A placoid, hyperreflective band at the level of the GCL and IPL was visible in OCT which spared the outer retina, at the time of diagnosis and 1 month later. An oropharyngeal swab test was performed for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ribonucleic acid (RNA), immunoglobulin G (IgG) and immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) determination. Real-time reverse-transcriptase polymerase chain reaction (RT-PCR) was negative. ELISA testing and a third rapid antibody detection test performed 7 days after the onset of symptoms were positive.ConclusionsOcular signs and symptoms in COVID-19 cases are rarely reported, but may be underestimated, especially those that affect the retina and occur in asymptomatic or paucisymptomatic cases. We present a case of COVID-19 diagnosis based on retinal ophthalmic examination.

Surgical Transplantation of Human RPE Stem Cell-Derived RPE Monolayers into Non-Human Primates with Immunosuppression.

SummaryRecent trials of retinal pigment epithelium (RPE) transplantation for the treatment of disorders such as age-related macular degeneration have been promising. However, limitations of existing strategies include the uncertain survival of RPE cells delivered by cell suspension and the inherent risk of uncontrolled cell proliferation in the vitreous cavity. Human RPE stem cell-derived RPE (hRPESC-RPE) transplantation can rescue vision in a rat model of retinal dystrophy and survive in the rabbit retina for at least 1 month. The present study placed hRPESC-RPE monolayers under the macula of a non-human primate model for 3 months. The transplant was able to recover in vivo and maintained healthy photoreceptors. Importantly, there was no evidence that subretinally transplanted monolayers underwent an epithelial-mesenchymal transition. Neither gliosis in adjacent retina nor epiretinal membranes were observed. These findings suggest that hRPESC-RPE monolayers are safe and may be a useful source for RPE cell replacement therapy.

Utility of spectral domain OCT in differentiating optic disc drusen from papilledema in children

The purpose of this study was to test the diagnostic accuracy of optical coherence tomography (OCT) in differentiating optic disc drusen (ODD) from papilledema in children. Retrospective cross-sectional study at a tertiary-care pediatric hospital. Children with high-quality OCT imaging of ODD or papilledema. Quantitative OCT parameters and qualitative OCT features were compared for diagnostic accuracy. There were 41 eyes with ODD and 21 eyes with papilledema. Both the quantitative and qualitative OCT parameters showed highly statistically significant differences between ODD and papilledema (p ≤ 0.01 for all). For quantitative parameters (Bruch's membrane opening and retinal nerve fiber layer thicknesses), the area under the curve from the receiver operator curves ranged from 0.81 to 0.90. For qualitative parameters, the sensitivity for ODD ranged from 27% to 100% and specificity ranged from 67% to 100%. The presence of at least 1 of 3 qualitative OCT parameters (hyporeflective boot-shaped area, isolated/clustered hyperreflective bands, or signal-poor regions in the core) had a sensitivity of 90% and a specificity of 100% for ODD. Both quantitative and qualitative OCT parameters differed significantly between ODD and papilledema in this cohort of children. A combination of several qualitative OCT features had high sensitivity for ODD while effectively ruling out papilledema.

Elevated advanced glycation end products are associated with subfoveal ellipsoid zone disruption in diabetic macular edema.

Purpose:Advanced glycation end products (AGEs), due to increased production and a slow turnover rate, serve as mediators of “metabolic memory” even after the resolution of hyperglycemia. A prospective study was undertaken to evaluate the association of AGEs with subfoveal ellipsoid zone (EZ) disruption in diabetic macular edema (DME).Methods:A tertiary-care-center-based cross-sectional study included 40 consecutive cases with DME and 20 healthy controls in the age group of 40–65 years. All the study subjects underwent spectral-domain optical coherence tomography (SD-OCT) for cross-sectional imaging of the retina. The EZ was defined as a hyperreflective band below the external limiting membrane. The disruption of EZ was graded as intact EZ and disrupted EZ. Serum AGEs were assessed by assay of Nε-carboxymethyl-lysine (Nε-CML) using the standard protocol. Data were analyzed statistically.Results:Subfoveal EZ disruption was noted in 80% (32/40) of the cases of DME. In the cases without EZ disruption, visual acuity (LogMAR VA) was 0.60 ± 0.52, whereas in cases with EZ disruption, LogMAR VA was 0.96 ± 0.56 (P < 0.001). In the cases without EZ disruption, Nε-CML was 94.31 ± 57 ng/mL, whereas in cases with EZ disruption Nε-CML was 120.64 ± 71.98 ng/mL (P < 0.001).Conclusion:In DME, increased levels of AGEs are significantly associated with EZ disruption on SD-OCT.

Enhanced Depth Imaging Optical Coherence Tomography of Optic Nerve Head Drusen in Children.

To assess the utility of enhanced depth imaging optical coherence tomography (EDI-OCT), compared with other conventional imaging modalities, for detecting and characterizing optic nerve head drusen (ONHD) in children. We report a retrospective cross-sectional case series of consecutive pediatric patients (age ≤16 years) with ONHD confirmed using B-scan ultrasonography. All eyes were evaluated using spectral-domain OCT of the optic nerve head in conventional (non-EDI) and EDI modes, fundus autofluorescence (FAF), and standard automated perimetry. Detection rates and the capacity to characterize ONHD were compared between EDI-OCT, non-EDI-OCT, and FAF. Twenty-eight eyes of 15 patients (mean age 11 years; 60% female) were identified with definite ONHD that were confirmed by B-scan ultrasound. Among the technologies, EDI-OCT, non-EDI-OCT, FAF, and automated perimetry had findings consistent with ONHD in 24, 21, 18, and 4 eyes, respectively. EDI-OCT had a significantly better detection capability (86% of eyes) compared with FAF (P = 0.04) but not with non-EDI-OCT (P = 0.15). Similar to results previously reported in adult patients, EDI-OCT detected ONHD at different levels of depth; most were located anterior to the lamina cribrosa. ONHD detected by EDI-OCT appeared as hypo-reflective ovoid regions bordered by hyper-reflective material or as isolated hyper-reflective bands without a hypo-reflective core. The mean greatest diameter of ONHD seen on EDI-OCT was 449.7 (SD ±114.1) μm. EDI-OCT detects ONHD in most eyes identified as having drusen on B-scan ultrasonography. This technique has the potential to be an effective alternative first-line diagnostic and monitoring tool for ONHD, particularly for detecting buried drusen in children.

Quantification of Translaminar Pressure Gradient (TLPG) With Continuous Wireless Telemetry in Nonhuman Primates (NHPs).

PurposeRecent retrospective clinical and animal studies suggest that cerebrospinal fluid pressure (CSFP) is important in glaucoma pathogenesis. Intraocular pressure (IOP) and CSFP are the driving components of translaminar pressure (TLP = IOP – CSFP), which acts across the lamina cribrosa (LC) thickness to create the translaminar pressure gradient (TLPG = TLP/LC thickness).MethodsWe developed an implantable wireless telemetry system based on a small piezoelectric sensor with low temporal drift. IOP, measured in the anterior chamber, and intracranial pressure (ICP), measured in the brain parenchyma (as a surrogate for CSFP) were measured at 200 Hz in three male rhesus macaques (nonhuman primates, NHPs) on a 10% duty cycle (15 seconds of every 150-second period). Three-dimensional LC thickness was autosegmented as the mean thickness of the visible hyperreflective band in 48 radial spectral-domain optical coherence tomography b-scans centered on the optic nerve head.ResultsResults indicated the rank order of IOP, ICP, TLP, and TLPG for waking, sleeping, and 24-hour periods averaged across all days. NHP 150110 had the highest IOP and ICP in all periods; however, it had the lowest TLPG in all periods due to its relatively thick LC. The other two NHPs showed similar shifts in the rank order of possible glaucoma risk factors.ConclusionsIOP is the only modifiable and readily measurable pressure-based risk factor for glaucoma. However, other potential risk factors such as ICP, TLP, and TLPG, as well as their rank-order patterns, differed compared to IOP across subjects, demonstrating that a comprehensive view of relevant risk factors is warranted.Translational RelevanceFuture studies should consider including CSFP, TLP, and TLPG in addition to IOP as potential risk factors when assessing eye-specific glaucoma susceptibility.

Optical coherence tomographic features of macular telangiectasia type 2: Korean Macular Telangiectasia Type 2 Study\u2014Report No. 1

We analysed the imaging findings of macular telangiectasia (MacTel) type 2 in Korea using spectral domain optical coherence tomography (SD-OCT) and investigated their relationship with visual acuity and clinical stages. A retrospective multicentre cross-sectional study was conducted in six tertiary hospitals in Korea and included 129 patients. We analysed all the SD-OCT images encompassing the macular area. Hyporeflective cavities (77.7%) were the most frequently detected abnormalities in SD-OCT. Disruption of the external limiting membrane, ellipsoid zone, and interdigitation zone were found in 67 (40.4%), 87 (52.4%), and 94 eyes (56.6%), respectively. Four eyes (2.4%) had lamellar macular hole, and five eyes (3.0%) full-thickness macular hole. Neovascularisation, either subretinal or intraretinal, was found in 14 eyes (8.4%). Eyes with outer retinal hyperreflective band disruption had lower visual acuity than those without them. The presented characteristic clinical features of OCT in MacTel type 2 can not only aid in differentiating this disease from others but are also helpful for better judgement of the disease stage in daily clinical practice. Inner retinal hyporeflective cavities without outer retinal abnormalities on SD-OCT, although classified as severity scale 3, could be considered a relatively early stage in the disease process in terms of vision.

Paracentral acute middle maculopathy and the organization of the retinal capillary plexuses.

The retinal capillary vasculature serves the formidable role of supplying the metabolically active inner and middle retina. In the parafoveal region, the retinal capillary plexuses (RCP) are organized in a system of three capillary layers of varying retinal depths: the superficial capillary plexus (SCP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP). While the dynamic flow through these plexuses is complex and not completely understood, current research points to a hybrid model that includes both parallel and in series components in which blood flows in a predominantly serial direction between the superficial vascular complex (SVC) and deep vascular complex (DVC). Each capillary plexus autoregulates independently, so that under most conditions the retinal vasculature supplies adequate blood flow and oxygen saturation at varying depths despite diverse environmental stressors. When the flow in the deep vascular complex (i.e. ICP and DCP) fails, an ischemic lesion referred to as Paracentral Acute Middle Maculopathy (PAMM) can be identified. PAMM is an optical coherence tomography (OCT) finding defined by the presence of a hyperreflective band at the level of the inner nuclear layer (INL) that indicates INL infarction caused by globally impaired perfusion through the retinal capillary system leading to hypoperfusion of the DVC or specifically the DCP. Patients present with an acute onset paracentral scotoma and typically experience a permanent visual defect. Lesions can be caused by a diverse set of local retinal vascular diseases and systemic disorders. PAMM is a manifestation of the retinal ischemic cascade in which the mildest forms of ischemia develop at the venular end of the DCP, i.e. perivenular PAMM, while more severe forms progress horizontally to diffusely involve the INL, and the most severe forms progress vertically to infarct the inner retina. Management is targeted toward the identification and treatment of related vasculopathic and systemic risk factors.

Dark without pressure retinal changes in a paediatric age group.

We aim to describe the clinical and imaging characteristics of young children with dark without pressure- a well-defined area of dark retina in the mid periphery associated with attenuated hyperreflective outer segment bands on spectral domain OCT. Retrospective medical chart review. We reviewed the charts and retinal images of children with dark without pressure (DWP) seen in the paediatric eye clinic that had undergone retinal imaging. We identified 6 children (3 males, 3 females) ranging in age from 3 to 13 years with DWP lesions. These were an incidental finding in children referred for other disorders. The lesions spared the macula and were typically in the mid-peripheral retina. In those children who could cooperate with detailed imaging, the DWP lesions were hypoautofluorecent on fundus autofluorescence imaging and OCT imaging showed reduced reflectance of the outer segments and EZ line as has been described in older children and adults. In two of the six subjects a DWP lesion appeared in an area of previously normal fundus; in no subjects did the lesion resolve over the period of follow up. The clinical and imaging characteristics of DWP lesions are similar in young children to those described in adults. The site of dysfunction appears to be at the level of the outer retina, but the precise cause is unknown. Recognition of this benign disorder will prevent patient anxiety and unnecessary further investigation.

Paracentral acute middle maculopathy-review of the literature.

Paracentral acute middle maculopathy (PAMM) is a recently identified spectral-domain optical coherence tomography (SD-OCT) finding characterized by a hyper-reflective band spanning the inner nuclear layer (INL), which typically evolves to INL atrophy in later stages. Typical clinical features include the sudden onset of one or multiple paracentral scotomas, normal or mild reduction in visual acuity, and a normal fundus appearance or a fundus with a deep grayish lesion. Although its pathophysiology is not yet fully understood, ischemia at the level of the intermediate and deep capillary plexa has been demonstrated to play a major role. Since its first description, an increasing number of publications on PAMM have been published in ophthalmology scientific journals. The purpose of this study is to provide a review of the current literature on PAMM.

Evaluation and grading of Kayser–Fleischer ring in Wilson disease by Scheimpflug camera

Evaluation the anterior segment parameters of Wilson disease patients with Kayser-Fleischer ring, the diagnostic power of Scheimpflug imaging for Kayser-Fleischer ring and suggest a scoring system. A total of 44 eyes of 22 Wilson disease patients with Kayser-Fleischer ring and 40 right eyes of 40 healthy age matched subjects were enrolled to the study. Serum ceruloplasmin and urine copper/24 hours levels were recorded. Anterior segment parameters including steep and flat keratometry, corneal thickness at central, 2, 4, 6, 8 and 10 mm, anterior chamber angle width, volume and depth, corneal volume, pupillary diameter were evaluated by Scheimpflug imaging. Images of cornea were scored according to Kayser-Fleischer ring size. Serum ceruloplasmin level was below 10 mg/dL in 17 patients and was 12, 18.5, 20, 22, 37 mg/dl in the remaining five patients. Urinary copper/24 hours was 249.55 ± 304.14 (23-1050) µg/day. Central corneal thickness and corneal thickness at 2 mm were statistically different (p values 0.02, 0.04, respectively). Scheimpflug images apparently showed Kayser-Fleischer ring as a hyper-reflective band at the corneal endothelial surface. Kayser-Fleischer ring in 24 eyes was grade 1, 16 eyes were grade 2 and 4 eyes were grade 3. Scheimpflug imaging seems to be a helpful diagnostic tool for detecting and grading the Kayser-Fleischer ring. Corneal thickness in Wilson disease patients with Kayser-Fleischer ring tends to be higher, so that the possible affection in corneal thickness should be kept in mind for clinical evaluation of these patients.

Real-time intraoperative dynamics of white cataract-intraoperative optical coherence tomography-guided classification and management.

To evaluate morphological characteristics and intraoperative dynamics of different types of white cataract using intraoperative optical coherence tomography (iOCT). Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. Prospective interventional study. Fifty eyes with white cataract undergoing phacoemulsification were evaluated. The primary outcome measure was the classification of white cataract based on morphology and intraoperative dynamics on iOCT. The secondary outcome measure was rhexis-related complications. Four types of white cataract were identified based on iOCT-type I (9 eyes), type II (3 eyes), type III (24 eyes), and type IV (14 eyes). Type I had regularly arranged lamellar cortical fibers, type II had continuous hyperreflective bands of cortical fibers with intralenticular clefts, type III had intralenticular clefts combined with areas of homogenous ground-glass appearance, and type IV had homogenous ground-glass appearance of the anterior lens cortex. Capsulorhexis in type I cataract was uneventful. In type II cataract, cortical bulge was observed in the anterior chamber on creating the initial nick, indicating raised intralenticular pressure (ILP) with an imminent risk of rhexis extension. A bimanual irrigation/aspiration was performed until lowering of ILP was observed on iOCT. In types III and IV, fluid release was observed on initiation of rhexis leading to partial (type III) or complete (type IV) lowering of ILP, with a mild-moderate risk of capsulorhexis extension. A continuous curvilinear capsulorhexis was achieved in all cases, with no case of posterior capsular tear or vitreous loss. Intraoperative OCT helped elucidate intraoperative dynamics of the spectrum of white cataracts and facilitates completion of capsulorhexis.

Differences in the presentation of stage 1 macular holes illustration by optical coherence tomography.

To present two different phases of progression of Gass stage 1 foveolar detachment to lamellar or full-thickness macular holes revealed with spectral domain optical coherence tomography. This is an observational study. The medical records of four patients (four eyes) with foveolar detachment that had evolved into stage 1 macular holes were compared. The patients manifested neither co-existing myopia nor any other ocular pathology. At each consultation, best-corrected visual acuity, dilated fundus examination, and spectral domain optical coherence tomography were performed to ascertain whether the foveolar detachment was associated with posterior vitreal detachment. In two of the eyes, and at an early phase of the disease, an incomplete posterior vitreal detachment and vitreal adhesion at the head of the optic nerve were observed. In the other two cases, the traction was not antero-posterior but tangential and had been effected by thickening of the inner limiting membrane or by the presence of a discrete epiretinal membrane in the papillomacular area; the posterior vitreal detachment was complete. In the former two cases and in one of the latter, the foveolar detachments had progressed to full-thickness macular holes. The visual acuities were better in the latter than in the former two eyes. Two different pathological mechanisms appear to underlie the formation of macular holes: The optical coherence tomography-guided classification of Gass stage 1 macular hole as an antero-posterior traction with a triangular foveolar detachment has to be distinguished from a tangential traction and a complete posterior vitreal detachment. Tangential traction is typically associated with a more dome-shaped or irregular foveolar detachment and a hyper-reflective band at the vitreoretinal interface.

Interpretation of OCT and OCTA images from a histological approach: Clinical and experimental implications.

Optical coherence tomography (OCT) and OCT angiography (OCTA) have been a technological breakthrough in the diagnosis, treatment, and follow-up of many retinal diseases, thanks to its resolution and its ability to inform of the retinal state in seconds, which gives relevant information about retinal degeneration. In this review, we present an immunohistochemical description of the human and mice retina and we correlate it with the OCT bands in health and pathological conditions. Here, we propose an interpretation of the four outer hyperreflective OCT bands with a correspondence to retinal histology: the first and innermost band as the external limiting membrane (ELM), the second band as the cone ellipsoid zone (EZ), the third band as the outer segment tips phagocytosed by the pigment epithelium (PhaZ), and the fourth band as the mitochondria in the basal portion of the RPE (RPEmitZ). The integrity of these bands would reflect the health of photoreceptors and retinal pigment epithelium. Moreover, we describe how the vascular plexuses vary in different regions of the healthy human and mice retina, using OCTA and immunohistochemistry. In humans, four, three, two or one plexuses can be observed depending on the distance from the fovea. Also, specific structures such as vascular loops in the intermediate capillary plexus, or spider-like structures of interconnected capillaries in the deep capillary plexus are found. In mice, three vascular plexuses occupy the whole retina, except in the most peripheral retina where only two plexuses are found. These morphological issues should be considered when assessing a pathology, as some retinal diseases are associated with structural changes in blood vessels. Therefore, the analysis of OCT bands and OCTA vascular plexuses may be complementary for the diagnosis and prognosis of retinal degenerative processes, useful to assess therapeutic approaches, and it is usually correlated to visual acuity.