En Face Optical Coherence Tomography Analysis to Assess the Spectrum of Perivenular Ischemia and Paracentral Acute Middle Maculopathy in Retinal Vein Occlusion

Exploring Patient Demographics and Presence of Retinal Vascular Disease in Paracentral Acute Middle Maculopathy

PURPOSE

To investigate the sociodemographic profile, the association with retinal vascular diseases (RVD) and systemic comorbidities, and visual outcomes of patients with paracentral acute middle maculopathy (PAMM) in a large, ethnically diverse single-center cohort.

DESIGN

Retrospective cohort study.

METHODS

Electronic health record query for all patients presenting with PAMM at Moorfields Eye Hospital, London, was completed. Detailed demographic, clinical, and systemic information were collected and analyzed.

RESULTS

A total of 78 eyes of 78 patients with confirmed PAMM were included in the study. Forty patients (51.3%) presented with no RVD, 20 patients (25.6%) with retinal vein occlusion (RVO), 16 patients (20.5%) with retinal artery occlusion (RAO), and 2 patients (2.6%) with concomitant RAO and RVO. Patients with PAMM+RAO were older than those with RVO (P = .02) and more likely to have a history of major adverse cardiovascular events (MACE) (P = .01), with a significantly worse presenting best corrected visual acuity (BCVA) (20/50) compared to patients with RVO (P = .02) and no RVD (P < .001). Individuals with isolated PAMM had a significantly higher prevalence of previous MACE (P = .04) and sickle cell disease (SCD) (P = .04) compared to those with RVO. At the last follow-up, 64 patients (85.3%) had a good BCVA (>20/32).

CONCLUSIONS

The significant association of PAMM with RVD supports the hypothesis of an ischemic etiology. Individuals with isolated PAMM had a higher prevalence of MACE and SCD. Thus, it is important to prompt immediate referral for a comprehensive systemic evaluation. Across the whole cohort, PAMM was associated with good BCVA improvement during follow-up, indicating a good visual prognosis.

PARACENTRAL ACUTE MIDDLE MACULOPATHY WITH SICKLE CELL TRAIT

PURPOSE

To report a case of paracentral acute middle maculopathy in a pediatric patient with sickle cell trait.

METHODS

The patient was evaluated with a comprehensive ophthalmic examination, optical coherence tomography, optical coherence tomography angiography, and fluorescein angiography.

RESULTS

Acute loss of vision occurred immediately after an uneventful scleral buckling procedure for retinal detachment in a 16-year-old female patient. Retinal imaging studies confirmed the occurrence of paracentral acute middle maculopathy, an ischemic condition characterized by infarction of the inner nuclear layer of the retina caused by hypoperfusion of the intermediate and deep capillary plexuses. Laboratory evaluation was only remarkable for sickle cell trait. Over a course of 3 months after the loss of vision, visual acuity improved from 20/1,000 to 20/20, and optical coherence tomography lesion resolved to a parafoveal area of inner and middle retinal layer thinning. Paracentral scotoma corresponding to the atrophic area persisted.

CONCLUSION

Dehydration because of the presurgical nil-per-os status and transient increase in intraocular pressure during the buckling surgery may have predisposed this patient with sickle cell trait to a sickling event that caused localized ischemia in the middle retina's end-capillaries. Avoiding long nil-per-os status, being mindful of transient intraocular pressure elevation during scleral buckling procedures, and presurgical hemoglobin electrophoresis in at-risk populations are recommended to prevent sickling attacks during retinal surgeries in individuals with sickle cell trait.

En face OCT analysis of Bietti's crystalline dystrophy

Objective

To describe the multimodal imaging features, including en face optical coherence tomography (OCT), of Bietti's crystalline dystrophy (BCD).

Methods

Wide field fundus photography, autofluorescence (FAF) imaging, and cross sectional and en face OCT were performed in a case of BCD. The level of the crystals in the retina were analyzed.

Results

A 42-year-old patient was referred for retinal evaluation with nyctalopia, photophobia and metamorphopsia. Retinal examination and wide field color fundus photography were remarkable for bilateral crystalline deposits in the posterior pole and midperipheral retina. Wide field FAF showed extensive nummular atrophy of the retinal pigment epithelium (RPE) in the macula and periphery. Spectral-domain (SD) OCT illustrated bilateral chorioretinal atrophy in the macula. En face SD OCT captured the hyperreflective crystals in various retinal layers, depending on the selected segmentation. The patient was diagnosed with BCD and genetic testing confirmed the diagnosis (CYP4V positive for two variants).

Conclusion

In this case report, we describe the multimodal imaging features of Bietti's Crystalline Dystrophy. Wide field FAF illustrated diffuse nummular RPE atrophy in the posterior pole and periphery and en face OCT captured the hyperreflective crystals in different layers of the retina.

PARACENTRAL ACUTE MIDDLE MACULOPATHY ASSOCIATED WITH SEVERE PLASMODIUM FALCIPARUM MALARIA

PURPOSE

To report a case of bilateral paracentral acute middle maculopathy lesions on spectral domain-optical coherence tomography(OCT) secondary to severe Plasmodium falciparum malaria.

METHODS

Retrospective case report. Spectral domain-OCT, ultra-widefield fluorescein angiography, and OCT angiography were performed and analyzed.

RESULTS

A 54-year-old healthy man presented with acute vision loss in both eyes few days after being diagnosed with severe Plasmodium falciparum malaria. Ophthalmoscopic examination was unremarkable, but near-infrared reflectance imaging showed patchy hyporeflective areas located at the terminal tips of the venous branches. Corresponding spectral-domain OCT demonstrated alternating bands of hyperreflectivity involving the inner nuclear layer, consistent with skip paracentral acute middle maculopathy lesions. Optical coherance tomography angiography illustrated corresponding flow signal loss at the level of the deep capillary plexus. Ultra-widefield fluorescein angiography showed peripheral retinal vein staining and capillary nonperfusion.

CONCLUSION

Paracentral acute middle maculopathy may be an OCT manifestation of malarial retinopathy associated with severe Plasmodium falciparum infection.

Retinal Findings and Cardiovascular Risk: Prognostic Conditions, Novel Biomarkers, and Emerging Image Analysis Techniques

Many retinal diseases and imaging findings have pathophysiologic underpinnings in the function of the cardiovascular system. Myriad retinal conditions, new imaging biomarkers, and novel image analysis techniques have been investigated for their association with future cardiovascular risk or utility in cardiovascular risk prognostication. An intensive literature search was performed to identify relevant articles indexed in PubMed, Scopus, and Google Scholar for a targeted narrative review. This review investigates the literature on specific retinal disease states, such as retinal arterial and venous occlusions and cotton wool spots, that portend significantly increased risk of future cardiovascular events, such as stroke or myocardial infarction, and the implications for personalized patient counseling. Furthermore, conditions diagnosed primarily through retinal bioimaging, such as paracentral acute middle maculopathy and the newly discovered entity known as a retinal ischemic perivascular lesion, may be associated with future incident cardiovascular morbidity and are also discussed. As ever-more-sophisticated imaging biomarkers and analysis techniques are developed, the review concludes with a focused analysis of optical coherence tomography and optical coherence tomography angiography biomarkers under investigation for potential value in prognostication and personalized therapy in cardiovascular disease.

Presumed Müller Cell Activation in Multiple Evanescent White Dot Syndrome

Purpose

The purpose of this study was to investigate the foveal changes occurring in multiple evanescent white dot syndrome (MEWDS) using multimodal imaging techniques with a specific focus on hyper-reflective dots (HRDs).

Methods

This was a retro-prospective observational study including 35 eyes with active MEWDS. Structural and en face optical coherence tomography (OCT) was performed, with follow-up visits at 2 weeks, 6 weeks, and 2 months from baseline. HRD percentage area (HRD % area) was calculated in a 600 µm fovea centered circle on en face OCT, after background subtraction and image binarization. HRD % area was compared with 23 fellow control eyes. Longitudinal changes in the HRD % areas were assessed using repeated-measure statistics.

Results

HRDs were observed as scattered hyper-reflective spots on the vitreoretinal interface on en face OCT images, colocalizing with HRDs or vertical hyper-reflective lines on structural OCT images. The baseline evaluation showed a significantly higher HRD % area in MEWDS eyes compared to fellow eyes (0.10 ± 0.03 vs. 0.08 ± 0.04, P = 0.01). The HRD % area correlated positively with LogMAR visual acuity and inversely with the duration of symptoms. Longitudinal analysis revealed a significant reduction in the HRD % area over time. There was no significant interaction between the rate of HRD disappearance and clinical or demographic factors at baseline.

Conclusions

As HRD potentially represents the end-feet projections of activated Müller cells on the retinal surface, this study supports the involvement of Müller cells in the pathogenesis of the disease. The findings highlight the potential of en face OCT imaging for monitoring the progression of MEWDS.

Henle fiber layer hemorrhage associated with combined central retinal vein occlusion and cilioretinal artery occlusion: a case report

BACKGROUND

The purpose of this study is to describe a patient who experienced simultaneous central retinal vein and cilioretinal artery occlusions, as well as perifoveal hemorrhage in the Henle fiber.

CASE PRESENTATION

A 67-year-old Iranian woman presented with a 3-day history of reduced vision in her left eye. Venous tortuosity and retinal hemorrhage were observed in the retina, together with whitened regions around the fovea, consistent with the diagnosis of central retinal vein occlusion in conjunction with cilioretinal artery occlusion. In structural and en face optical coherence tomography, star-shaped hemorrhages were observed around the fovea, which looked hyperreflective in the Henle fiber layer.

CONCLUSIONS

We present a case of central retinal vein occlusion exacerbated by cilioretinal occlusion and hemorrhage in the Henle fiber layer. The hemorrhage is most likely the result of increased intraluminal pressure in the deep capillary plexus.

Benefits of a Laser Chorioretinal Anastomosis Plus Ranibizumab vs Ranibizumab Alone for Central Retinal Vein Occlusion: 4-Year Results

PURPOSE

To evaluate what clinical gains can be achieved over conventional treatment with ranibizumab alone for central retinal vein occlusion (CRVO) when causal pathology is additionally addressed successfully with a laser-induced chorio-retinal anastomosis (L-CRA).

DESIGN

Two-year extension of prospective, randomized controlled clinical trial.

METHODS

A total of 58 patients with macular edema secondary to CRVO were randomized 1:1 to receive either an L-CRA (n = 29) or sham procedure (n = 29) at baseline and then monthly intravitreal ranibizumab 0.5 mg. Outcomes (best corrected visual acuity [BCVA], central subfield thickness [CST], injection requirements) were monitored in the monthly pro re nata (PRN) ranibizumab phase from months 7 to 48.

RESULTS

Injection requirements for patients with a functioning L-CRA (24 of 29) during the monthly PRN period from 7 to 24 months were a mean (95% CI) of 2.18 (1.57, 2.78) injections compared to 7.07 (6.08, 8.06) (P < .0001) for control (ranibizumab alone). These decreased further over the next 2 years to 0.29 (0.14, 0.61) compared to 2.20 (1.68, 2.88) (P < .001) for the third year and 0.25 (0.11, 0.56) and 1.84 (1.34, 2.54) for the fourth year (P < .001). Mean BCVA was statistically different at all follow-up time points from month 7 through month 48 for the group with the functioning L-CRA compared to the control monotherapy group. This improved to 14.06 letters at month 48 (P = .009). There was no difference in CST between any of the groups over the 48 months of follow-up.

CONCLUSION

For CRVO patients, addressing causal pathology in addition to conventional therapy improves BCVA and reduces injection requirements.

High Variation in Inner Retinal Reflectivity Predicts Poor Visual Outcome in Patients With Central Retinal Vein Occlusion: SCORE2 Report 21

Purpose

To assess the association of a novel spectral domain optical coherence tomography biomarker with 6-month visual acuity in in the Study of COmparative Treatments for REtinal Vein Occlusion 2.

Methods

Spectral domain optical coherence tomography volume scans were evaluated for inner retinal hyperreflectivity, quantified by optical intensity ratio (OIR) and OIR variation. Baseline visual acuity letter score (VALS), baseline OCT biomarkers, and month 1 OIR were correlated with VALS at month 6. Regression trees, a machine learning technique yielding readily interpretable models, were used to assess for variable interaction.

Results

Only baseline VALS correlated positively with month 6 VALS in multivariate regression. Regression trees detected a novel functional and anatomical interaction in a subgroup. Among patients with a baseline VALS worse than 43, those with an OIR variation at month 1 of more than 0.09 had a mean of 13 fewer letters of vision at 6 months compared with patients with an OIR variation of 0.09 or less.

Conclusions

Baseline VALS was the strongest predictor of month 6 VALS. Regression tree analysis detected an interaction effect, in which higher OIR variation at month 1 predicted worse 6-month VALS in patients with low VALS at baseline. OIR variation may serve as a predictor for poor visual outcome despite treatment of macular edema secondary to retinal vein occlusion in patients with poor vision at baseline.

Translational Relevance

Pixel heterogeneity in three-dimensional OCT data may serve as measure of disruption of the retinal laminations, and this factor may carry visually prognostic value.

Paracentral acute middle maculopathy immediately following internal carotid endovascular repair

Paracentral acute middle maculopathy (PAMM) can result from decreased perfusion to retinal and choroidal circulations meeting in the inner nuclear layer (INL) and outer plexiform layer (OPL). Although ischemia in these layers is rare, certain procedures place patients at risk for possible events, such as cardiopulmonary bypass, coronary angiography, and endovascular coil embolization. We report the case of a 70-year-old woman with a sudden-onset left paracentral scotoma following internal carotid endovascular repair. Currently no treatment or preventive technique is available. Additional ischemic events can occur if a preventable cause is not identified.

Paracentral Acute Middle Maculopathy as a Specific Sign of Arteritic Anterior Ischemic Optic Neuropathy

PURPOSE

The purpose of this study is to assess the diagnostic accuracy of paracentral acute middle maculopathy (PAMM) in the setting of anterior ischemic optic neuropathy (AION) to distinguish arteritic (A-AION) from nonarteritic (NA-AION) type.

DESIGN

Retrospective cross-sectional diagnostic evaluation.

METHODS

PAMM was evaluated by 3 physicians blinded to diagnosis using macular spectral-domain optical coherence tomography. We studied 45 patients with AION. Of those, 28 had NA-AION and 17 had A-AION. The study was conducted in the Department of Ophthalmology at the Hospital of Marseille-Assistance Publique, France, from January 1, 2018, to March 31, 2022.

RESULTS

PAMM were only found in the A-AION group (N = 4) (P = .0143). As a distinctive sign of A-AION, we found a specificity of 100% (95% IC, 88.06%-100%) and a positive predictive value of 100%. In contrast, sensitivity and negative predictive value were lower, 19.1% (95% IC, 5.5-42.0) and 63.0% (95% CI, 58.1-67.7), respectively.

CONCLUSIONS

The PAMM finding is highly specific for A-AION in the setting of AION. According to our results, macular spectral-domain optical coherence tomography looking for PAMM should be performed with any patient presenting with AION.

Recent Advances in Clinical Applications of Imaging in Retinal Diseases

Many diseases that cause visual impairment, as well as systemic conditions, manifest in the posterior segment of the eye. With the advent of high-speed, high-resolution, reliable, and noninvasive imaging techniques, ophthalmologists are becoming more dependent on ocular imaging for disease diagnosis, classification, and management in clinical practice. There are rapid advances on the indications of multimodal retinal imaging techniques, including the application of ultra-widefield fundus angiography, fundus autofluorescence, optical coherence tomography, as well as optical coherence tomography angiography. This review summarizes and highlights the clinical applications, latest indications, and interpretations of multimodal imaging in age-related macular degeneration, polypoidal choroidal vasculopathy, diabetic macular edema, central serous chorioretinopathy, diabetic retinopathy, retinal vein occlusion, and uveitis.

Paracentral Acute Middle Maculopathy As the Presenting Sign of Ischemic Cardiomyopathy

Paracentral acute middle maculopathy (PAMM) is a type of ischemic maculopathy affecting intermediate and deep retinal capillary plexuses. A typical presentation is acute onset scotoma with or without vision loss. It is characterized by greyish-white parafoveal lesions. Sometimes very subtle lesions can be missed on clinical examination. The main diagnostic modality is spectral domain optical coherence tomography (SD-OCT) wherein focal or multifocal lesions are seen as bands of hyperreflectivity in the inner nuclear and outer plexiform layers. This entity can be associated with systemic microvascular diseases. Here, we report an interesting case of PAMM as the only presenting sign in a patient with ischemic cardiomyopathy, highlighting the necessity for a thorough systemic examination in such patients.

Quantitative approaches in multimodal fundus imaging: State of the art and future perspectives

When it first appeared, multimodal fundus imaging revolutionized the diagnostic workup and provided extremely useful new insights into the pathogenesis of fundus diseases. The recent addition of quantitative approaches has further expanded the amount of information that can be obtained. In spite of the growing interest in advanced quantitative metrics, the scientific community has not reached a stable consensus on repeatable, standardized quantitative techniques to process and analyze the images. Furthermore, imaging artifacts may considerably affect the processing and interpretation of quantitative data, potentially affecting their reliability. The aim of this survey is to provide a comprehensive summary of the main multimodal imaging techniques, covering their limitations as well as their strengths. We also offer a thorough analysis of current quantitative imaging metrics, looking into their technical features, limitations, and interpretation. In addition, we describe the main imaging artifacts and their potential impact on imaging quality and reliability. The prospect of increasing reliance on artificial intelligence-based analyses suggests there is a need to develop more sophisticated quantitative metrics and to improve imaging technologies, incorporating clear, standardized, post-processing procedures. These measures are becoming urgent if these analyses are to cross the threshold from a research context to real-life clinical practice.

Retinal ischemic cascade: New insights into the pathophysiology and imaging findings

Retinal ischemia gives rise to a complex spectrum in which the cumulative profile of ischemia of the middle and inner retina can be highly variable. We reviewed the current knowledge on paracentral acute middle maculopathy (PAMM) pathophysiology and accompanying risk factors, the middle and inner retinal vasculature and blood flow, and the vulnerability of the middle retina in vaso-occlusive disorders. The inner nuclear layer (INL) is easily affected by slight degrees of retinal hypoperfusion and ischemia. INL infarction starts at perivenular sites, manifesting as skip PAMM lesions and a fern-like appearance in cross-sectional and en face views, respectively. With horizontal progression, INL infarction may develop into diffuse globular PAMM. If vertical progression occurs, the entire middle and inner portions of the retina can be affected. Transmural infarction of the middle and inner retina would be at the end of this spectrum. This gradient of ischemic progression resembles an ischemic cascade. We review the evidence supporting the term "retinal ischemic cascade," which encompasses a broad continuum of manifestations with roots in middle retinal infarction. With this terminology, variations in spatial and temporal progression and resolution of ischemia can also be delivered; it further enables addressing the possible associations between the middle and inner retinal ischemic patterns.

Association of Resolved Paracentral Acute Middle Maculopathy Lesions with Diabetic Retinopathy

Purpose

To evaluate the association between paracentral acute middle maculopathy (PAMM) lesions and diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA).

Methods

Thirteen diabetic patients without DR, 13 patients with mild nonproliferative DR (NPDR), 18 patients with moderate-to-severe NPDR, and 20 patients with proliferative DR (PDR) were included in this retrospective study. For each patient, 6 mm × 6 mm macular OCTA scans of both eyes were reviewed for the presence of acute and resolved PAMM lesions.

Results

Among diabetic patients with and without DR, 49 (94.9%) and 7 (53.8%) patients demonstrated small resolved PAMM lesions, respectively. The odds ratio for the presence of resolved PAMM lesions in the eye with DR compared to the eye of diabetic patient without DR was 21.8 (P < 0.001, 95% confidence interval 7.0-67.8). In the mild NPDR group, moderate-to-severe NPDR group, and the PDR group, 11 (84.6%), 18 (100.0%), and 20 (100.0%) patients demonstrated resolved PAMM lesions, respectively. There was a statistically significant increasing prevalence of PAMM lesions as the severity of DR increased (P < 0.001).

Conclusion

Small resolved PAMM lesions are a common form of ischemic retinal lesions in DR.

Clinical and Morphologic Characteristics of Perivenular Fernlike Leakage on Ultrawide-field Fluorescein Angiography

PURPOSE

To analyze the spectrum of the perivenular fernlike leakage on ultrawide-field fluorescein angiography (UWFA) and discuss its potential implications in the current understanding of the retinal venous outflow.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Eyes presenting with fernlike patterns of dye leakage on UWFA were included in this study.

METHODS

Analysis of the clinical characteristics and multimodal imaging findings using UWFA and wide-angle swept-source OCT-angiography (SS-OCTA).

MAIN OUTCOME MEASURES

The disease spectrum, anatomic origin, and clinical implications of this fernlike leakage.

RESULTS

Multimodal retinal images from 40 eyes of 29 patients with fernlike leakage on UWFA were studied. The underlying etiologies included a wide range of inflammatory disorders, including pars planitis (18 eyes) and central retinal vein occlusion (2 eyes). On UWFA, the fernlike leakage originated from the retinal capillaries and venules directly adjacent to the veins and spared the periarterial zone. This perivenular fernlike leakage involved the far periphery in all cases and progressed more diffusely and centripetally in cases with more severe intraocular inflammation. On wide-angle SS-OCTA, the impairment of deep capillary plexus (DCP) flow signals precisely colocalized with the perivenular fernlike leakages identified on UWFA.

CONCLUSIONS

The fernlike leakage on UWFA refers to the distinctive perivenular dye leakage that originates from the retinal capillaries and venules. Multimodal imaging correlation suggests that the predominant impairment is at the level of the DCP. The axial symmetry of the fernlike leakage with the veins and sparing of the periarterial zone may support the dominant venous role of the DCP.

Paracentral Acute Middle Maculopathy Revealing a Giant Aortic Aneurysm

BACKGROUND

This report describes a case with paracentral acute middle maculopathy revealing a giant aortic aneurysm.

CASE DESCRIPTION

A 41-year-old man presented with unilaterally unexplained sudden vision loss in the left eye. Fundoscopy revealed a slightly pale r -26etinal reflex in the superior retinal hemifield. SDOCT revealed blurred boundaries between retinal segments and prominent edema in the middle retinal layers. OCTA revealed decreased vascular density in the deep capillary plexus. FA showed low arterial circulation mainly in the superior retinal hemifield. Humphrey VFT revealed an inferior altitudinal defect in the left eye, implying a related circulatory disturbance in the corresponding region.A thorough systemic work-up, including a cardiovascular etiological investigation, revealed giant aortic aneurysm in the ascending aorta, necessitating emergency surgery.

CONCLUSION

This report highlights the importance of a systemic etiological investigation in patients with PAMM to rule out any potential cardiovascular issues.

PARACENTRAL ACUTE MIDDLE MACULOPATHY IN CENTRAL RETINAL VEIN OCCLUSION COMPLICATING AMYLOID LIGHT-CHAIN AMYLOIDOSIS

PURPOSE

To describe a case of paracentral acute middle maculopathy associated with central retinal vein occlusion in a patient affected by amyloid light-chain amyloidosis.

METHODS

One patient with confirmed diagnosis of amyloid light-chain amyloidosis, displaying paracentral acute middle maculopathy and central retinal vein occlusion, was recruited. The patient underwent complete ophthalmologic examination and multimodal imaging, including: fundus autofluorescence, fluorescein angiography, indocyanine green angiography, spectral-domain optical coherence tomography, and optical coherence tomography angiography.

RESULTS

Fundus autofluorescence showed a ferning pattern, corresponding to linear hypofluorescence in late-phase indocyanine green angiography and delayed venous filling, detected by fluorescein angiography. Structural optical coherence tomography revealed a hyper-reflective line located in the outer plexiform layer, corresponding to the prominent middle limiting membrane, along with several placoid lesions. Optical coherence tomography angiography found that the superficial capillary plexus was preserved, whereas vessel density was reduced in both the deep capillary plexus and the choriocapillaris. After 1 year of follow-up, the patient achieved an almost complete morphological recovery.

CONCLUSION

Multimodal imaging described in depth the morphological features of a case of combined paracentral acute middle maculopathy and central retinal vein occlusion in a patient affected by amyloid light-chain amyloidosis.

Macular Vascular Imaging and Connectivity Analysis Using High-Resolution Optical Coherence Tomography

Purpose

To characterize macular blood flow connectivity in vivo using high-resolution optical coherence tomography (HighRes OCT).

Methods

Cross-sectional, observational study. Dense (6-µm interscan distance) perifoveal HighRes OCT raster scans were performed on healthy participants. To mitigate the limitations of projection-resolved OCT-angiography, flow and structural data were used to observe the vascular structures of the superficial vascular complex (SVC) and the deep vascular complex. Vascular segmentation and rendering were performed using Imaris 9.5 software. Inflow and outflow patterns were classified according to vascular diameter and branching order from superficial arteries and veins, respectively.

Results

Eight eyes from eight participants were included in this analysis, from which 422 inflow and 459 outflow connections were characterized. Arteries had direct arteriolar connections to the SVC (78%) and to the intermediate capillary plexus (ICP, 22%). Deep capillary plexus (DCP) inflow derived from small-diameter vessels succeeding ICP arterioles. The most prevalent outflow pathways coursed through superficial draining venules (74%). DCP draining venules ordinarily merged with ICP draining venules and drained independently of superficial venules in 21% of cases. The morphology of DCP draining venules in structural HighRes OCT is distinct from other vessels crossing the inner nuclear layer and can be used to identify superficial veins.

Conclusions

Vascular connectivity analysis supports a hybrid circuitry of blood flow within the human parafoveal macula.

Translational Relevance

Characterization of parafoveal macular blood flow connectivity in vivo using a precise segmentation of HighRes OCT is consistent with ground-truth microscopy studies and shows a hybrid circuitry.

AUTOFLUORESCENT TIMELINE OF SPOTS AND DOTS IN MULTIPLE EVANESCENT WHITE DOT SYNDROME

PURPOSE

To describe the recovery timeline of spots and dots in multiple evanescent white dot syndrome.

METHODS

Sequential multimodal retinal imaging including fundus autofluorescence and cross-sectional and en face optical coherence tomography was performed to track the development and resolution of spots and dots in a case of multiple evanescent white dot syndrome.

RESULTS

En face optical coherence tomography showed that the spots are the result of ellipsoid zone loss and are hyperautofluorescent due to unmasking of the underlying retinal pigment epithelium autofluorescence. Conversely, the dots are hyperreflective with cross-sectional and en face optical coherence tomography and hyperautofluorescent, which we propose may be due to accumulation of degenerated photoreceptor material including fluorophores with autofluorescent capability such as precursors of A2E. The earlier resolution of the hyperautofluorescent spots allowed for later detection of the hyperautofluorescent dots.

CONCLUSION

This case report illustrates the different recovery timelines of spots and dots in multiple evanescent white dot syndrome. Although both lesion types are hyperautofluorescent, the mechanism of autofluorescence is distinctive and may be explained by their contrasting pathoanatomy.

PARACENTRAL ACUTE MIDDLE MACULOPATHY FOLLOWING ORAL INTAKE OF SUMATRIPTAN

PURPOSE

The purpose of this report was to describe a case with paracentral acute middle maculopathy after oral intake of sumatriptan.

METHODS

Case presentation.

RESULTS

One patient showed typical findings on fundoscopic examination and optical coherence tomography consistent with paracentral acute middle maculopathy following oral intake of sumatriptan.

CONCLUSION

Sumatriptan may be a trigger for paracentral acute middle maculopathy.

A multi-scale/multi-physics model for the theoretical study of the vascular configuration of retinal capillary plexuses based on OCTA data

The retinal tissue is highly metabolically active and is responsible for translating the visual stimuli into electrical signals to be delivered to the brain. A complex vascular structure ensures an adequate supply of blood and oxygen, which is essential for the function and survival of the retinal tissue. To date, a complete understanding of the configuration of the retinal vascular structures is still lacking. Optical coherence tomography angiography has made available a huge amount of imaging data regarding the main retinal capillary plexuses, namely the superficial capillary plexuses (SCP), intermediate capillary plexuses (ICP) and deep capillary plexuses (DCP). However, the interpretation of these data is still controversial. In particular, the question of whether the three capillary plexuses are connected in series or in parallel remains a matter of debate. In this work, we address this question by utilizing a multi-scale/multi-physics mathematical model to quantify the impact of the two hypothesized vascular configurations on retinal hemodynamics and oxygenation. The response to central retinal vein occlusion (CRVO) and intraocular pressure (IOP) elevation is also simulated depending on whether the capillary plexuses are connected in series or in parallel. The simulation results show the following: (i) in the in series configuration, the plexuses exhibit a differential response, with DCP and ICP experiencing larger pressure drops than SCP; and (ii) in the in parallel configuration, the blood flow redistributes uniformly in the three plexuses. The different vascular configurations show different responses also in terms of oxygen profiles: (i) in the in series configuration, the outer nuclear layer, outer plexiform layer and inner nuclear layer (INL) are those most affected by CRVO and IOP elevation; and (ii) in the in parallel configuration the INL and ganglion cell layer are those most affected. The in series results are consistent with studies on paracentral acute middle maculopathy, secondary to CRVO and with studies on IOP elevation, in which DCP and ICP and the retinal tissues surrounding them are those most affected by ischemia. These findings seem to suggest that the in series configuration better describes the physiology of the vascular retinal capillary network in health and disease.

Paracentral Acute Middle Maculopathy and the Ischemic Cascade: Toward Interventional Management

PURPOSE

To present select cases of paracentral acute middle maculopathy (PAMM) demonstrating progressive vascular occlusion and the ischemic cascade and illustrate scenarios in which therapeutic intervention may be considered.

DESIGN

Perspective.

METHODS

Review and interpretation of selected literature, with perspective on the evaluation and management of patients with PAMM lesions. Multimodal imaging of 3 illustrative cases of PAMM are presented, including cross-sectional and en face optical coherence tomography (OCT), with progressive vascular occlusion and evidence of the ischemic cascade noted in 2 of the cases.

RESULTS

All 3 cases showed evidence of PAMM at baseline, including perivenular PAMM in 2 cases. Progression from a mild central retinal vein occlusion (CRVO) to a more severe CRVO was noted in the first case, while the second case progressed from an incomplete to complete central retinal artery occlusion (CRAO). In the third case, there was resolution of PAMM lesions associated with partial CRAO after the patient began taking aspirin.

CONCLUSIONS

Perivenular PAMM can be the only presenting sign of retinal vascular occlusion. In such cases, it is important to differentiate between partial CRVO and incomplete CRAO as the underlying cause. We provide guidance on making this important distinction, which plays a critical role in directing the nature and urgency of the systemic work-up. In patients with PAMM caused by partial retinal arterial occlusion, a benign empirical approach, such as low-dose aspirin (81 mg), may be reasonable to reduce the likelihood of subsequent vision loss from progression to complete arterial occlusion. A clinical trial, however, is necessary to support such a strategy.

Total venous nature of retinal deep capillary plexus inferred by continuity of prominent middle limiting membrane sign in optical coherence tomography

This study aimed to theoretically identify the vascular nature of the deep capillary plexus (DCP) by examining patients presenting with both paracentral acute middle maculopathy (PAMM) and prominent middle limiting membrane (p-MLM) sign and p-MLM sign alone in spectral-domain optical coherence tomography (SD-OCT). A retrospective review of the medical records of patients with retinal vein or artery occlusion from two tertiary medical centers was performed. Consecutive patients with a clinical diagnosis of all categories of retinal artery occlusion (RAO) and retinal vein occlusion (RVO) (branch or central and ischemic or non-ischemic) who had undergone SD-OCT imaging from January 2015 to May 2020 were recruited and their p-MLM signs and PAMM lesions were assessed. We included 118 patients who presented with p-MLM sign with or without PAMM lesions. Amon them, 40 were female and 78 were male, with a mean age of 61.1 years. Of the 109 patients with both p-MLM sign and PAMM lesions, 23 had branch RAO, two had branch RVO, 67 had central RAO, 13 had central RVO, and four had a combination of central RAO and central RVO. All nine patients with the p-MLM sign alone had central RVO accompanied by cystoid macular edema. In all the enrolled patients, the hyperreflective lines of the p-MLM sign were continuous, regardless of the type of PAMM lesions. In conclusion, when PAMM and p-MLM sign are examined together, further proof regarding the possible complete venous nature of the vasculature of the retinal DCP might be speculated.

Vascular Microanatomy of Small Resolved Paracentral Acute Middle Maculopathy Lesions

PURPOSE

To study microvascular characteristics of small resolved paracentral acute middle maculopathy (PAMM) lesions in fellow eyes of patients with unilateral retinal vein occlusion (RVO).

DESIGN

Prospective cross-sectional study.

PARTICIPANTS

Patients with prior unilateral branch or central RVO and OCT evidence of resolved PAMM in the fellow, otherwise normal, eye were recruited prospectively and imaged with OCT angiography (OCTA).

METHODS

The resolved PAMM lesions were identified as focal areas of inner nuclear layer thinning over an anteriorly displaced outer plexiform layer (OPL). En face OCTA projections showing the location and size of the resolved PAMM lesions were created using 2 OPL segmentation lines with -9-μm and 0-μm offsets, and the cumulative distribution was evaluated. Anterior to the resolved PAMM lesions, vessels in the superficial vascular plexus were traced to identify small arterioles supplying the affected areas.

MAIN OUTCOME MEASURES

Cumulative spatial distribution on small resolved PAMM lesions.

RESULTS

From 24 fellow eyes of 24 patients with unilateral RVO (15 men and 9 women; mean age, 62.1 ± 13.6 years), 152 resolved PAMM lesions were identified. Of these lesions, 130 (85.5%) were found within the perifoveal region, and only 12 (7.9%) were found within the temporal quadrant. Of 28 lesions analyzed, the arteriole supplying the affected area was a single side branch of a larger vessel, with only 3 supplied by a terminal branch.

CONCLUSIONS

Small resolved PAMM lesions in fellow eyes of patients with unilateral RVO are most prevalent in perifoveal regions supplied by side branches of low-order retinal arteries.

Identification and Characterization of Epivascular Glia Using En Face Optical Coherence Tomography

PURPOSE

The purpose of this study was to describe the clinical features of epivascular glia (EVG) using en face optical coherence tomography (OCT).

DESIGN

Retrospective cross-sectional study.

METHODS

Single-institution en face OCT images were reviewed. Eyes displaying EVG were captured with manual internal limiting membrane (ILM) segmentation and analyzed with customized segmentation . A random age- and sex-matched control group was selected to determine relative epiretinal membrane (ERM) prevalence.

RESULTS

Characteristic hyper-reflective ILM plaques with dendrite-like radiations were identified using en face OCT and displayed vascular predilection. A total of 161 eyes with EVG (the EVG group) and 2,315 eyes without EVG (control group) were identified from a total cohort of 1,298 patients (or 2,476 eyes). The prevalence of EVG was 161 of 2,476 eyes (6.5%) and 119 of 1,298 patients (9.2%) in the cohort. Mean age was 79.3 ± 10.7 years old in the EVG group and 55.9 ± 24.6 years old in the control group (P <.001). An advanced posterior vitreous detachment (PVD) stage was more common in the EVG group (grade 3: 41.7%; grade 4: 48.6%) than in the control group (grade 3: 18.5%; grade 4: 26.9%; P <.001). Contractile ERM was present in 71 of 161 eyes (44.1%) with EVG compared to 30 of 161 eyes (18.6%) in a random age- and sex-matched control cohort without EVG (P <.001).

CONCLUSIONS

EVG previously described with histopathology and scanning electron microscopy can be identified using en face OCT. In this study, these lesions were associated with older age, pseudophakia, and advanced PVD, supporting the role of Müller cell activation through ILM breaks triggered by PVD, a pathogenic mechanism proposed by previous studies.

PARACENTRAL ACUTE MIDDLE MACULOPATHY ASSOCIATED WITH PHOSPHODIESTERASE-5 INHIBITOR THERAPY

PURPOSE

To present an atypical case of paracentral acute middle maculopathy occurred upon awakening in the morning within hours after phosphodiesterase-5 (PDE-5) inhibitor consumption at bedtime.

METHODS

Multimodal retinal imaging findings, including fluorescein angiography, spectral domain optical coherence tomography, optical coherence tomography angiography, and microperimetry of a particular case of paracentral acute middle maculopathy lesion that follow the distribution of the cilioretinal artery.

RESULTS

A 52-year-old healthy man presented with an acute paracentral scotoma in his left eye upon awakening in the morning, after the use of a PDE-5 inhibitor pill the previous night. Spectral domain optical coherence tomography illustrated a hyperreflective band-like lesion at the level of the inner nuclear layer, consistent with a diagnosis of paracentral acute middle maculopathy, along the course of the cilioretinal artery that appeared normally perfused with fluorescein angiography. Optical coherence tomography angiography showed a perfusion deficit and capillary pruning of the retinal deep capillary plexus, with preserved intermediate capillary plexus, that colocalized with the paracentral scotoma confirmed with microperimetry.

CONCLUSION

To our knowledge, this is the first report of paracentral acute middle maculopathy after the use of PDE-5 inhibitor. Nocturnal arterial hypotension exacerbated by the vasodilatory effect of the PDE-5 inhibitor may have caused transient cilioretinal artery hypo/nonperfusion and insufficiency. Paracentral acute middle maculopathy may represent the earliest form of ischemia in the central macular region, occurring after a milder vascular insult.

En Face Optical Coherence Tomography Imaging of Foveal Dots in Eyes With Posterior Vitreous Detachment or Internal Limiting Membrane Peeling

Purpose

To analyze the morphology of foveal hyperreflective dots (HRD) identified with en face optical coherence tomography (OCT) and evaluate the effects of internal limiting membrane (ILM) peeling and posterior vitreous detachment (PVD) on the number of these lesions.

Methods

Retrospective cross-sectional study of patients with OCT angiography and en face OCT. Using en face OCT, superficial HRD lying on the foveal floor were measured and quantitated in eyes with ILM peel and in the fellow nonsurgical eyes. Eyes with foveal PVD were also compared to fellow eyes without foveal PVD. High-magnification en face OCT was also performed to better understand the morphology of HRD in the fovea.

Results

Eyes that underwent ILM peel (n = 10) displayed fewer HRD (P = 0.012) compared to control fellow nonoperated eyes. In eyes with foveal PVD, the mean number of HRD was numerically greater, but without statistical significance, compared to the contralateral eye without foveal PVD. High-magnification en face OCT illustrated HRD with irregular shapes and fine cilia-like or dendriform extensions. Average length of HRD was between 15 to 21 µm in all four groups.

Conclusions

HRD decreased in eyes with ILM peeling by en face OCT compared with fellow nonoperated eyes and exhibited a glial cell-like morphology and size closely resembling the white dot fovea described previously using scanning electron microscopy. HRD may represent processes of activated retinal glia, possibly Muller cells, that traverse defects in the ILM.

Clinical Characteristics of Paracentral Acute Middle Maculopathy in Eyes with Retinal Vascular Occlusion Diseases in Chinese Patients

Aim

To investigate the incidence and clinical characteristics of paracentral acute middle maculopathy (PAMM) and its relationship with prominent middle limiting membrane (p-MLM) sign in eyes with retinal artery occlusion (RAO) or retinal vein occlusion (RVO) in a Chinese clinical setting.

Methods

In this retrospective observational study from January 2015 to May 2020, multimodal imaging data of 807 eyes including 555 consecutive patients with RVO or 252 consecutive patients with RAO were reviewed. All patients were scanned using the spectrum-domain optical coherence tomography (OCT), and some of them underwent color fundus photography, fundus fluorescence angiography, en face OCT, and OCT angiography.

Results

PAMM was detected in 49 eyes of 49 RAO patients and 29 eyes of 29 RVO patients. The mean ages at presentation were 64.49 ± 13.90 years and 54.00 ± 18.48 years in RAO and RVO patients (P=0.006), respectively. Eyes with RAO were more prone to develop PAMM (19.44% [49/252] vs. 5.23% [29/555]; P < 0.001). Of the 78 eyes with PAMM, 24 eyes (7 eyes with RVO and 17 eyes with RAO) were found with p-MLM sign. An interesting phenomenon that had been overlooked before was that the hyperreflective line of the p-MLM sign was usually continuous, regardless of the type of PAMM lesion.

Conclusions

This series is the largest to date to describe the clinical characteristics of PAMM and p-MLM sign in Chinese patients. The incidence of PAMM and p-MLM sign in patients with RAO was relatively higher than that in patients with RVO. These signs alone probably represent milder ischemia and prompt us to carry out a comprehensive and meticulous examination to prevent the further development of the disease. In addition, the hyperreflective line of the p-MLM sign was usually continuous, which could support the totally venous nature of the retinal deep capillary plexus to some extent.

Spatial distribution of diabetic capillary non-perfusion

OBJECTIVE

To evaluate the distribution of capillary non-perfusion (CNP) in superficial and deep capillary plexuses (SCP and DCP) in eyes with diabetic retinopathy (DR).

METHODS

In this retrospective case series, macular optical coherence tomography angiography (OCTA) images were obtained from eyes with DR without diabetic macular edema (DME). The area of CNP in SCP and DCP was delineated using an automated approach after excluding the foveal avascular zone (FAZ) and major retinal vessels. The distribution and spatial correlation of the CNP in each layer were analyzed.

RESULTS

Forty-three eyes of 27 patients with DR with a mean age of 59.10 ± 9.05 years were included. The mean CNP area in SCP was statistically significantly higher than DCP (0.722 ± 0.437 mm² vs. 0.184 ± 0.145 mm² , respectively, p < .001). There was a statistically significant association between mean BCVA (0.28 ± 0.21 logMAR) and CNP area in DCP (p = .01). After automated subtraction of CNP areas in DCP from SCP, 25.43 ± 15.05% of CNP areas in the DCP had co-localized CNP areas in SCP. The CNP percentage was statistically significantly different between the concentric rings on foveal center, both in SCP and in DCP (both p < .001) showing a decreasing trend from the outer ring toward the center.

CONCLUSION

In DR, SCP is more ischemic than DCP. This is in contrast to the previously described oxygenation-dependent ischemic cascade following acute retinal vascular occlusions. This study provides further insight into the retinal ischemia in DR.

PARACENTRAL ACUTE MIDDLE MACULOPATHY AFTER ENDOVASCULAR COIL EMBOLIZATION

PURPOSE

To describe two cases of paracentral acute middle maculopathy (PAMM) that occurred unilaterally after endovascular coil embolization.

METHODS

Medical records including ophthalmic examinations of two PAMM cases were retrospectively reviewed.

RESULTS

The first case was a 64-year-old woman with hyperlipidemia and chronic sinusitis. The second case was a 49-year-old man with hypertension, hyperlipidemia, tension headache, and vertigo. Both cases exhibited paracentral scotomas just after endovascular coil embolization. Ophthalmoscopy showed multiple faint white-yellow lesions in each affected eye. Optical coherence tomography showed hyper-reflective bands that were mainly observed in the inner nuclear layer and corresponded to the PAMM lesions. Optical coherence tomography angiography revealed variable degrees of abnormal vasculature from slight dilation, decreased visualization, to nonvisualization in the superficial capillary plexuses and similar capillary changes in deep capillary plexuses.

CONCLUSION

We described two cases with PAMM that occurred after endovascular coil embolization, which was a new precursor cause of PAMM. Our results demonstrate that optical coherence tomography angiography is especially useful for not only diagnosis, but also for follow-up evaluations in patients with PAMM.

Widefield en face optical coherence tomography monitoring of the peri-venular fern-like pattern of paracentral acute middle maculopathy

Purpose

To demonstrate the ability of widefield en face swept source optical coherence tomography (OCT) imaging to monitor peri-venular fern-like patterns of paracentral acute middle maculopathy (PAMM) associated with retinal arterial occlusions.

Observations

The peri-venular fern-like pattern of PAMM was diagnosed on the 12 × 12 mm en face structural OCT images from three patients. Fluorescein angiography images were unremarkable. Over time, all three patients demonstrated significant improvement in visual acuity with resolution of their peri-venular PAMM.

Conclusions

The peri-venular fern-like pattern of PAMM is usually associated with retinal vein occlusions, but we identified three cases with this pattern in eyes with presumed incomplete retinal arterial occlusions. Our cases support the ischemic cascade theory that begins within the deep capillary plexus and ascends in the retina depending on the severity of the ischemic event. Using the 12 × 12 mm en face structural OCT images, we are able to demonstrate a wider area of ischemia in PAMM compared with the traditional 6 × 6 mm scans.

Prevalence of subclinical retinal ischemia in patients with cardiovascular disease - a hypothesis driven study

BACKGROUND

Cardiovascular disease is the leading cause of mortality and disability worldwide. A noninvasive test that can detect underlying cardiovascular disease has the potential to identify patients at risk prior to the occurrence of adverse cardiovascular events. We sought to determine whether an easily observed imaging finding indicative of retinal ischemia, which we term 'retinal ischemic perivascular lesions' (RIPLs), could serve as a biomarker for cardiovascular disease.

METHODS

We reviewed optical coherence tomography (OCT) scans of individuals, with no underlying retinal pathology, obtained at UC San Diego Health from July 2014 to July 2019. We identified 84 patients with documented cardiovascular disease and 76 healthy controls. OCT scans were assessed for evidence of RIPLs. In addition, the 10-year atherosclerotic cardiovascular disease (ASCVD) risk calculator was used to risk-stratify the subjects into four different categories.

FINDINGS

Patients with documented cardiovascular disease had higher number of RIPLs compared to healthy controls (2.8 vs 0.8, p < 0.001). After adjusting for age, sex, smoking history, systolic blood pressure and triglycerides, cholesterol and hemoglobin A1C levels, each RIPL was associated with an odds ratio of having cardiovascular disease of 1·60 (1.09-2>37). The number of RIPLs in individuals with intermediate and high 10-year ASCVD risk scores was higher than in those with low ASCVD risk scores (1.7 vs 0.64, p = 0.02 and 2.9 vs 0.64, p 0.002, respectively).

INTERPRETATION

The presence of RIPLs, which are anatomical markers of prior retinal ischemic infarcts, is suggestive of coexisting cardiovascular disease. RIPLs detection, obtained from routine retinal scans, may thus provide an additional biomarker to identify patients at risk of developing adverse cardiovascular events.

FUNDING

None.

Multimodal imaging for paracentral acute maculopathy; the diagnostic role of en face OCT

Background

To describe the features of multimodal imaging and the diagnostic role of en face OCT in the paracentral acute middle maculopathy (PAMM) spectrum.

Methods

In this observational case series, 5 eyes of 5 patients with acute PAMM were identified. Demographic characteristics as well as data regarding the underlying disease, presenting visual acuity (VA) and ophthalmic examination results were recorded. All patients underwent multimodal imaging within 3 days after symptom onset.

Results

The mean age of patients was 52.2 (range, 33–67) years. Systemic comorbidities including diabetes mellitus and hypertension were identified in two patients. Except for one patient diagnosed with isolated PAMM, other patients had signs of retinal vascular disease such as a cilioretinal artery or branch retinal artery obstruction, non-ischemic central retinal vein occlusion, or a combination of these vascular disorders. The central vision was preserved in two cases; however, the remaining cases presented with profound VA reduction. Different patterns of PAMM including arterial, globular, and fern-like were observed in en face OCT at deep capillary plexus (DCP) level. En face OCT images could precisely delineate the margin of the PAMM area. Optical coherence tomography angiography (OCTA) showed decreased vascular density in DCP. Unresolved projection artifact by conventional OCTA software was observed in DCP and choriocapillaris slabs in all cases.

Conclusion

En face structural OCT in PAMM can delineate the area of ischemia and the degree of foveal involvement. Unresolved projection artifact by conventional OCTA software in the PAMM area can be seen in DCP and choriocapillaris layers.

Volume Rendering of Dense B-Scan Optical Coherence Tomography Angiography to Evaluate the Connectivity of Macular Blood Flow

Purpose

To characterize macular blood flow connectivity using volume rendering of dense B-scan (DB) optical coherence tomography angiography (OCTA) data.

Methods

This was a prospective, cross-sectional, observational study. DB OCTA perifoveal scans were performed on healthy subjects using the Spectralis HRA+OCT2. A volumetric projection artifact removal algorithm and customized filters were applied to raw OCTA voxel data. Volume rendering was performed using a workflow on Imaris 9.5 software. Vascular graphs were obtained from angiographic data using the algorithm threshold-loops. Superficial arteries and veins were identified from color fundus photographs and connections between adjacent arteries and veins displayed using the shortest path algorithm. Connective pathway locations were analyzed with cross-sectional OCT and OCTA to determine their course through the superficial vascular complex (SVC) and the deep vascular complex (DVC).

Results

Fourteen eyes from seven subjects (mean age: 28 ± 5 years; 3 women) were included in this analysis. One hundred and twenty-six vascular connections were analyzed. In all cases, the shortest path connections between superficial arteries and veins coursed through the DVC. We did not identify shortest path connections confined to the SVC.

Conclusions

Volumetric analysis of vascular connectivity supports a predominantly in-series arrangement of blood flow between the SVC and DVC within the human perifoveal macula.

Plexus-specific retinal vascular anatomy and pathologies as seen by projection-resolved optical coherence tomographic angiography

Optical coherence tomographic angiography (OCTA) is a novel technology capable of imaging retinal vasculature three-dimensionally at capillary scale without the need to inject any extrinsic dye contrast. However, projection artifacts cause superficial retinal vascular patterns to be duplicated in deeper layers, thus interfering with the clean visualization of some retinal plexuses and vascular pathologies. Projection-resolved OCTA (PR-OCTA) uses post-processing algorithms to reduce projection artifacts. With PR-OCTA, it is now possible to resolve up to 4 distinct retinal vascular plexuses in the living human eye. The technology also allows us to detect and distinguish between various retinal and optic nerve diseases. For example, optic nerve diseases such as glaucoma primarily reduces the capillary density in the superficial vascular complex, which comprises the nerve fiber layer plexus and the ganglion cell layer plexus. Outer retinal diseases such as retinitis pigmentosa primarily reduce the capillary density in the deep vascular complex, which comprises the intermediate capillary plexus and the deep capillary plexus. Retinal vascular diseases such as diabetic retinopathy and vein occlusion affect all plexuses, but with different patterns of capillary loss and vascular malformations. PR-OCTA is also useful in distinguishing various types of choroidal neovascularization and monitoring their response to anti-angiogenic medications. In retinal angiomatous proliferation and macular telangiectasia type 2, PR-OCTA can trace the pathologic vascular extension into deeper layers as the disease progress through stages. Plexus-specific visualization and measurement of retinal vascular changes are improving our ability to diagnose, stage, monitor, and assess treatment response in a wide variety of optic nerve and retinal diseases. These applications will be further enhanced with the continuing improvement of the speed and resolution of the OCT platforms, as well as the development of software algorithms to reduce artifacts, improve image quality, and make quantitative measurements.

Paracentral acute middle maculopathy: from diagnosis toward clinical perspectives

In this review of literature, we reviewed the current state of knowledge on paracentral acute middle maculopathy (PAMM). The diversity of clinical manifestations, a variety of related cardiovascular and ocular conditions, as well as reported idiopathic cases, allow considering PAMM as a distinct clinical phenomenon or a syndrome. Taking into account already described and potential associations with systemic and ocular morbidity, PAMM may apply for a place of an important clinical biomarker not only for ocular but for systemic disorders in a broad cohort of patients. However, the understanding of the pathophysiology of PAMM and of its actual clinical significance is far from complete, and further studies are warranted.

Comparison of lamina cribrosa properties and the peripapillary vessel density between branch retinal vein occlusion and normal-tension glaucoma

PURPOSE

To compare the properties of the lamina cribrosa (LC) and the peripapillary vessel density between branch retinal vein occlusion (BRVO) and normal-tension glaucoma (NTG), using swept-source optical coherence tomography and optical coherence tomography angiography.

METHODS

This retrospective study included 21 eyes of 21 patients with BRVO and 43 eyes of 43 patients with NTG who were treated from June 2016 to September 2017. The anterior LC depth (ALCD) and LC thickness (LCT) at the mid-superior, central, and mid-inferior levels; the mean difference in ALCD; and the peripapillary vessel density in the superficial and deep capillary plexuses and the choriocapillaris were compared between groups.

RESULTS

ALCD at the mid-superior, central, and mid-inferior levels was significantly greater in the NTG group (P < 0.05), while LCT was comparable between the groups. The mean difference in ALCD was significantly greater in the BRVO group (P = 0.03). The peripapillary vessel density in the superotemporal segment of the superficial capillary plexus was significantly lower in the BRVO group, while the density in all segments of the choriocapillaris was significantly lower in the NTG group (P < 0.05 for all).

CONCLUSIONS

Our findings demonstrate that BRVO and NTG have different LC structures and peripapillary vessel densities.

PAMM and the ischemic cascade associated with radiation retinopathy

Purpose

To report a case of paracentral acute middle maculopathy (PAMM) and evidence of the ischemic cascade documented with spectral domain optical coherence tomography (SD-OCT) following radiation treatment of a choroidal melanoma.

Observations

A healthy young patient was evaluated for an asymptomatic choroidal nevus in the left eye. Fundus examination was remarkable for a choroidal melanocytic lesion that measured 1.8 mm in thickness by initial B-scan ultrasound. Clinical examination 6 months later showed growth of the tumor at several margins with new subretinal fluid, and a B-scan measured thickness of 1.9 mm. The lesion was diagnosed as a small choroidal melanoma and treated with gamma knife radiation with a dose of 3000 cGy. Sixteen months later, examination showed signs of radiation retinopathy including cotton wool spots and PAMM via SD-OCT and OCT angiography and evidence of the ischemic cascade (i.e., alternating zones of middle and combined middle and inner retinal layer infarction).

Conclusions

Radiation retinopathy can include signs of microvascular damage and ischemia including lesions such as cotton wool spots and PAMM. A case is presented in this report of radiation retinopathy with OCT evidence of PAMM and the ischemic cascade.

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.

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.

Paracentral Acute Middle Maculopathy as a Presenting Sign of CRAO in Sickle Cell Disease Treated with Tissue Plasminogen Activator

PURPOSE

We report the case of a 27-year-old monocular woman with history of sickle cell disease who received intra-arterial tissue plasminogen activator (tPA) after presenting with acute painless vision loss secondary to incomplete central retinal artery occlusion presenting as paracentral acute middle maculopathy (PAMM) in her left eye.

METHODS

Ultra-widefield fundus photography, ultra-widefield fluorescein angiography, en face ocular coherence tomography (OCT), and ocular coherence tomography angiography (OCTA) were obtained and reviewed, followed by cerebral angiography and infusion of intra-arterial tissue plasminogen activator (tPA).

RESULTS

A patient with a history of sickle cell disease presented with new onset of a dense central scotoma and visual acuity diminished to 20/200 from baseline 20/20 in her left eye. Fluorescein angiogram was non-diagnostic. OCT revealed perifoveal hyperreflective bands in the inner nuclear layer in a pattern characteristic of PAMM. The patient received intra-arterial tPA through her left ophthalmic artery shortly after presentation, resulting in a gradual restoration of visual acuity to 20/20 in the three months following the procedure.

CONCLUSIONS

This is the first report describing the use of intra-arterial tPA to treat incomplete central retinal artery occlusion presenting as a PAMM lesion in a patient with sickle cell disease.

Relationship Between Nerve Fiber Layer Hemorrhages and Outcomes in Central Retinal Vein Occlusion

Purpose

To evaluate the depth and pattern of retinal hemorrhage in acute central retinal vein occlusion (CRVO) and to correlate these with visual and anatomic outcomes.

Methods

Retinal hemorrhages were evaluated with color fundus photography and fluorescein angiography at baseline and follow-up. Snellen visual acuity (VA), central foveal thickness (CFT), extent of retinal ischemia, and development of neovascularization were analyzed.

Results

108 eyes from 108 patients were evaluated. Mean age was 63.6 ± 16.1 years with a predilection for the right eye (73.1%). Average follow-up was 17.2 ± 19.2 months. Mean VA at baseline was 20/126 and 20/80 at final follow-up. Baseline (P = 0.005) and final VA (P = 0.02) in eyes with perivascular nerve fiber layer (NFL) hemorrhages were significantly worse than in eyes with deep hemorrhages alone. Baseline CFT was greater in the group with perivascular hemorrhages (826 ± 394 µm) compared to the group with deep hemorrhages alone (455 ± 273 µm, P < 0.001). The 10 disc areas of retinal ischemia was more common in patients with perivascular (80.0%) and peripapillary (31.3%) versus deep hemorrhages alone (16.1%, P < 0.001). Neovascularization of the iris was more common, although this differrence was not significant, in the groups with peripapillary (14.3%) and perivascular (2.0%) NFL versus deep hemorrhages alone (0.0%).

Conclusions

NFL retinal hemorrhages at baseline correlate with more severe forms of CRVO, with greater macular edema, poorer visual outcomes, and greater risk of ischemia and neovascularization. This may be related to the organization of the retinal capillary plexus. The depth and pattern of distribution of retinal hemorrhages in CRVO may provide an easily identifiable early biomarker of CRVO prognosis.

Henle fibre layer haemorrhage: clinical features and pathogenesis

BACKGROUND

To describe the clinical presentation and characteristic imaging features of deep retinal haemorrhages primarily located in the Henle fibre layer (HFL) of the macula. The spectrum of aetiologies and a comprehensive theory of pathogenesis are presented.

METHODS

This is a retrospective, multicentre case series evaluating eyes with retinal haemorrhage in HFL. Clinical features, underlying aetiology, systemic and ocular risk factors, visual acuity, and multimodal imaging including fundus photography and cross-sectional and en face optical coherence tomography (OCT) are presented.

RESULTS

Retinal haemorrhages localised to HFL in 33 eyes from 23 patients were secondary to acute blunt trauma to the head (n=2), eye (n=1) and trunk (n=1), ruptured intracranial aneurysm (Terson's syndrome, n=3), general anaesthesia (n=1), epidural anaesthesia (n=1), hypertension with anaemia (n=1), decompression retinopathy (n=1), postvitrectomy with intraocular gas (n=1), retinal vein occlusion (n=7), myopic degeneration (n=2), macular telangiectasia type 2 (n=1), and polypoidal choroidal vasculopathy (n=1). Defining clinical features included deep retinal haemorrhage with feathery margin and petaloid pattern radiating from the fovea. OCT demonstrated characteristic hyper-reflectivity from the haemorrhage delineated by obliquely oriented fibres in the Henle layer. Spontaneous resolution of HFL haemorrhage occurred after 3 months in 15 patients with follow-up.

CONCLUSION

The characteristic petaloid-shaped, deep intraretinal haemorrhage with a feathery margin localised to HFL is associated with various disorders. The terminology 'Henle fiber layer hemorrhage (HH)' is proposed to describe the clinical and OCT findings, which may result from abnormal retinal venous pressure from systemic or local retinovascular disorders affecting the deep capillary plexus or from choroidal vascular abnormalities.

PARACENTRAL ACUTE MIDDLE MACULOPATHY IN A CASE OF HIGH-FLOW DIRECT CAROTID CAVERNOUS FISTULA

PURPOSE

To report a case of paracentral acute middle maculopathy in a patient with high-flow carotid cavernous fistula.

METHODS

A case report of a 53-year-old male patient who sustained an iatrogenic high-flow carotid cavernous fistula and secondary paracentral acute middle maculopathy.

RESULTS

At review 1-week postembolization of the carotid cavernous fistula, there was no significant improvement in visual acuity, tests of optic nerve function, external ophthalmoplegia, and ptosis. Spectral domain optical coherence tomography was performed, which revealed hyperreflectivity of the parafoveal plexiform layers of the right eye with ill-defined margins straddling the inner nuclear layer.

CONCLUSION

We suggest that spectral domain optical coherence tomography be performed in cases of high-flow direct carotid cavernous fistula where the best-corrected visual acuity is reduced out of keeping with other ophthalmic manifestations.