Patchy ischemic retinal whitening in acute central 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 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.

Hyperreflective Vasculature: A Negative Prognostic Sign for Retinal Vein Occlusion on Near-Infrared Reflectance Imaging

BACKGROUND AND OBJECTIVE

To investigate the clinical significance of hyperreflective vasculature visualized on near-infrared reflectance (NIR) in patients with retinal vein occlusion (RVO).

METHODS

In this retrospective study, RVO patients with NIR imaging and at least 1-year follow-up, and without confounding disease, were included. Two blinded independent graders identified vascular hyperreflectivity (HR) by detection of whiter signals in vessels. Visual acuity (VA), macular thickness (MT), and number of administered anti-vascular endothelial growth factor (anti-VEGF) injections were assessed.

RESULTS

RVO patients with HR (n = 20) and without HR (n = 31) demonstrated similarity in age, sex, and class of RVO. At presentation, the HR group had higher MT (P = 0.002) but no difference in VA (P = 0.1018). At 1 year, patients with HR had worse VA (P = 0.001), decreased MT (P = 0.011), and received more anti-VEGF injections (P < 0.001).

CONCLUSION

RVO patients with HR on NIR had significantly worse visual outcomes. Vascular HR on NIR imaging may be a biomarker, portending worse visual prognoses in RVO. [Ophthalmic Surg Lasers Imaging Retina 2023;54:266-270.].

Imaging in retinal vascular disease: A review

Retinal vascular diseases represent a broad field of ocular pathologies. Retinal imaging is an important tool for diagnosis, prognosis and follow up of retinal vascular diseases. It includes a wide variety of imaging techniques ranging from colour fundus photography and optical coherence tomography to dynamic diagnostic options such as fluorescein angiography, and optical coherence tomography angiography. The newest developments in respective imaging techniques include widefield imaging to assess the retinal periphery, which is of especial interest in retinal vascular diseases. Automatic image analysis and artificial intelligence may support the image analysis and may prove valuable for prognostic purposes. This review provides a broad overview of the imaging techniques that have been used in the past, today and maybe in the future to stage and monitor retinal vascular disease with focus on the main disease entities including diabetic retinopathy, retinal vein occlusion, and retinal artery occlusion.

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.

Clinical Features of Central Retinal Vein Occlusion in Young Patients

Retinal vein occlusion (RVO) is the second most common retinal vascular disease. Central RVO (CRVO), in which obstruction occurs posterior to the lamina cribrosa due to various causes, manifests with extensive venous tortuosity, dilatation of blood vessels in the four quadrants, and retinal hemorrhage. The presence of macular edema decreases visual acuity in patients with CRVO, especially in elderly patients with hypertension, hyperlipidemia, and diabetes. In the last decade, treatment modalities for CRVO have improved, with anti-vascular endothelial growth factor agents being widely used as treatment. However, there are cases of refractory or recurrent macular edema. Moreover, CRVO also occurs in young patients. This article reviews previous studies and case reports and summarizes the differences in etiological factors, clinical manifestations, treatment, and prognosis between young and elderly patients. Due to the low incidence of CRVO in young patients, clinical data from these age groups are limited. Hence, further studies are warranted to explore the differences between age groups to improve individualization of treatment of young patients.

CENTRAL RETINAL VEIN OCCLUSION IN YOUNG PATIENTS: Clinical Characteristics and Prognostic Factors

PURPOSE

To investigate the clinical characteristics and prognostic factors of young patients with central retinal vein occlusion (CRVO).

METHODS

This retrospective cohort study involved treatment-naïve patients with CRVO. Medical records regarding basic demographics, predisposing factors, ocular characteristics, and treatments were reviewed and compared according to age at CRVO onset.

RESULTS

We enrolled 263 patients, of whom 69 were younger patients. Younger patients had higher prevalence of nontraditional risk factors including physical or psychological stress (P = 0.032), hematologic abnormalities (P = 0.003), and better visual acuity at baseline and last visit (all P < 0.001) and were unlikely to undergo intravitreal injections (47.8 vs. 68.6%, P < 0.001) during follow-up. Younger patients had higher prevalence of paracentral acute middle maculopathy (28.1 vs. 4.7%, P < 0.001). Older age (odds ratio = 1.165, P = 0.028), male sex (odds ratio = 7.074, P = 0.034), coexisting renal disease (odds ratio = 7.845, P = 0.050), and poor baseline visual acuity (odds ratio = 16.069, P = 0.002) were significant risk factors for poor visual outcomes in young CRVO patients.

CONCLUSION

Younger CRVO patients had a milder clinical course with fewer treatments and were more likely to have nontraditional risk factors than older patients.

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.

Association of Optical Coherence Tomography Angiography of Collaterals in Retinal Vein Occlusion With Major Venous Outflow Through the Deep Vascular Complex

Importance

Analysis of collateral vessel formation following retinal vein occlusion may advance our understanding of the venous outflow anatomy in the macula.

Objective

To determine the location of collateral vessels with optical coherence tomography (OCT) angiography imaging.

Design, Setting, and Participants

Observational retrospective cohort study. Collateral vessel formation was studied with OCT angiography (OCTA) in patients with retinal vein occlusion (RVO). The study took place at 2 retinal practices (Vitreous Retina Macula Consultants of New York and Stein Eye Institute, University of California, Los Angeles), with patient records retrieved from March 2015 to August 2017. Data analysis was completed in November 2017.

Exposures

Collaterals identified with fundus photography and/or fluorescein angiography were analyzed with OCTA to determine their course through the superficial vascular plexus (SVP) and the deep vascular complex (DVC).

Main Outcomes and Measures

Collateral vessel pathways through the SVP and DVC were analyzed with cross-sectional and en face OCT and OCTA segmentation and color-coded volume renderings prepared from raw OCTA voxel data.

Results

From 23 eyes (22 branch and 1 hemispheric retinal vein occlusion ) of 23 patients (mean [SD] age, 73 [11] years), 101 collateral vessels were identified and analyzed (mean [SD], 4.4 [2.0]; range, 2-9 collateral per eye). On OCTA, the collaterals appeared as curvilinear dilated flow signals that connected veins across the horizontal raphe or veins on opposite sides of an occluded venous segment within the same retinal hemisphere. Of the 101 collaterals analyzed, all showed greater flow signal in the DVC, and all had some portion of their course identified within the DVC. No collaterals were found exclusively in the SVP. Volume renderings for 3 cases confirmed qualitatively that retinal collateral vessels course through the retina predominantly at the level of the DVC.

Conclusions and Relevance

Based on a limited number of cases, all collateral vessels associated with retinal vein occlusion were found to course through the DVC. The absence of collaterals isolated to the SVP supports a serial arrangement of the SVP and DVC, with venous drainage predominantly coursing through the DVC.

Misery Perfusion, Diffusive Oxygen Shunting and Interarterial Watershed Infarction Underlie Oxygenation-Based Hypoperfusion Maculopathy

PURPOSE

To describe and explain the entire range of acute ischemic macular damage that follows panretinal hypoperfusion from central retinal artery or vein occlusion.

DESIGN

Perspective article.

METHODS

To correlate the fundoscopic, fluorescein angiographic, oximetric, and optical coherence tomographic (OCT) features developing within the posterior inner retina following incremental reductions in arteriovenous perfusion pressure across the retinal circulation.

RESULTS

The spectrum of acute oxygenation-based hypoperfusion maculopathy (OHM) is consistent with that predictable from a modified Krogh cylinder model of tissue oxygenation. Diffusive oxygen shunting plays a significant role in the "artery-dominated" generation of ischemic signs during misery perfusion. Three major grades of OHM severity can be discerned according to the predominant oxygenation status of ganglion cells within the superficial inner retina, whether this is normoxic (OHM1), hypoxic (OHM2), or anoxic (OHM3). Densely opaque axoplasmic sentinels are arranged along normoxic/hypoxic interfaces in OHM2. In OHM1 and OHM2, relative hypermetabolism and interarterial watershed infarction of fundal interneurons (WIFI) underpin subtle middle-retinal opacification with periarterial sparing. The fundal signs are optimally displayed en face using autofluorescence imaging whereas cross-sectional OCT reveals Paques' plaque formation.

CONCLUSIONS

An exquisite and supremely accessible exhibition of classical oxygen physiopathology unfolds in eyes with panretinal hypoperfusion courtesy of the transparent ocular media and the pattern of macular neuroretinal opacification that evolves as upstream tissues extract oxygen to the detriment of tissues downstream. Recent attempts to overrule the simple conceptual framework embodied in WIFI have no plausible anatomical nor physiological basis. Overreliance on OCT can result in misdiagnosis.

Paracentral Acute Middle Maculopathy and the Ischemic Cascade Associated With Retinal Vascular Occlusion

PURPOSE

To analyze the spectrum of ischemia associated with paracentral acute middle maculopathy (PAMM) in eyes with acute retinal vascular occlusion and to describe an ischemic cascade.

DESIGN

A retrospective observational case series.

METHODS

Patients presenting with PAMM secondary to acute retinal vascular occlusion were identified. Analysis of multimodal imaging was performed at baseline and at follow-up visits to elucidate the patterns and progression of ischemia within the retinal layers.

RESULTS

Multimodal retinal imaging from 16 eyes of 16 patients with acute retinal vascular occlusion associated with PAMM was studied. Analysis of en face optical coherence tomography (OCT) segmentation of the inner nuclear layer (INL) identified distinct patterns of PAMM correlating with the severity of ischemia and not the type of occlusion. A perivenular fern-like PAMM pattern was associated with better visual outcomes (average final visual acuity was 20/25). This pattern was noted to sequentially progress in 2 cases to a diffuse globular PAMM pattern in the INL, or to a pattern of ischemia involving both the middle and inner retinal layers with commensurate vision loss. Globular patterns of PAMM or ischemia involving both the middle and inner retina correlated with poorer visual outcomes (average final visual acuity was counting fingers at 5.5 ft). These various patterns of ischemia developed in eyes with retinal vascular occlusions in which blood flow through the retinal capillary plexuses was present but was significantly reduced and delayed.

CONCLUSIONS

This study describes OCT findings suggestive of an ischemic cascade in eyes with retinal vascular occlusion. The middle retina at the level of the deep capillary plexus, especially at the venular pole, may be more vulnerable to ischemic injury.

Optical coherence tomography angiography

Optical coherence tomography (OCT) was one of the biggest advances in ophthalmic imaging. Building on that platform, OCT angiography (OCTA) provides depth resolved images of blood flow in the retina and choroid with levels of detail far exceeding that obtained with older forms of imaging. This new modality is challenging because of the need for new equipment and processing techniques, current limitations of imaging capability, and rapid advancements in both imaging and in our understanding of the imaging and applicable pathophysiology of the retina and choroid. These factors lead to a steep learning curve, even for those with a working understanding dye-based ocular angiography. All for a method of imaging that is a little more than 10 years old. This review begins with a historical account of the development of OCTA, and the methods used in OCTA, including signal processing, image generation, and display techniques. This forms the basis to understand what OCTA images show as well as how image artifacts arise. The anatomy and imaging of specific vascular layers of the eye are reviewed. The integration of OCTA in multimodal imaging in the evaluation of retinal vascular occlusive diseases, diabetic retinopathy, uveitis, inherited diseases, age-related macular degeneration, and disorders of the optic nerve is presented. OCTA is an exciting, disruptive technology. Its use is rapidly expanding in clinical practice as well as for research into the pathophysiology of diseases of the posterior pole.

Mystery of Retinal Vein Occlusion: Vasoactivity of the Vein and Possible Involvement of Endothelin-1

Retinal vein occlusion (RVO) is a common vascular disease of retina; however, the pathomechanism leading to RVO is not yet clear. In general, increasing age, hypertension, arteriosclerosis, diabetes mellitus, dyslipidemia, cardiovascular disorder, and cerebral stroke are systemic risk factors of RVO. However, RVO often occur in the unilateral eye and sometimes develop in young subjects who have no arteriosclerosis. In addition, RVO show different variations on the degrees of severity; some RVO are resolved without any treatment and others develop vision-threatening complications such as macular edema, combined retinal artery occlusion, vitreous hemorrhage, and glaucoma. Clinical conditions leading to RVO are still open to question. In this review, we discuss how to treat RVO in practice by presenting some RVO cases. We also deliver possible pathomechanisms of RVO through our clinical experience and animal experiments.

[Abnormal retinal artery perfusion and optical coherence tomography angiography]

INTRODUCTION

To analyze optical coherence tomography angiography (OCT-A) findings in patients with impaired retinal artery perfusion secondary to occlusion of the central retinal artery or its branches, cilioretinal artery occlusion or retinal vein occlusion (RVO).

METHODS

In this retrospective observational study of patients with impaired retinal artery perfusion, we recorded the results of clinical examination and multimodal imaging, including fluorescein angiography, spectral-domain (SD)-OCT, and OCT-A (Optovue) of the central 10 degrees with measurement of vascular density.

RESULTS

The files of 10 patients were analyzed (5 men, mean age: 63 years), including 3 retinal artery occlusions, 4 cilioretinal artery occlusions, isolated or combined with central retinal vein occlusion (CRVO), and 3 RVO with an arterial component. SD-OCT showed hyper-reflectivity of the inner nuclear layer consistent with paracentral acute middle maculopathy (PAMM) in the acute stage (8 eyes) resulting in retinal atrophy as early as the following month. OCT-A revealed capillary dropout in all patients with various degrees, the deep capillary plexus seemed to be more involved than the superficial plexus. A fern-like pattern was observed on en-face OCT in 4 eyes, outlining venular contours. Vascular density was significantly diminished (whole en-face density in the deep capillary plexus: 50.39 vs. 56.21 in the control group, P=0.001). On fluorescein angiography, reperfusion was observed in half of the eyes.

CONCLUSION

OCT-A can be very useful in patients with a transitory arterial occlusion by revealing involvement of the superficial and deep capillary plexus. It may enable a retrospective diagnosis in the case of reperfusion.

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

PURPOSE

To assess the spectrum of perivenular ischemia in eyes with retinal vascular obstruction (typically central or hemicentral retinal vein obstruction) using en face optical coherence tomography (OCT).

DESIGN

Retrospective observational case series.

METHODS

Eyes with recent retinal vascular occlusion illustrating paracentral acute middle maculopathy (PAMM) in a perivenular fern-like pattern with en face OCT were evaluated in this study. Multimodal retinal imaging including en face OCT segmentation of the inner nuclear layer was performed in all patients. Color fundus photography and fluorescein angiography (FA) images were used to create a vascular overlay of the retinal veins vs the retinal arteries to map the distribution of PAMM with en face OCT analysis.

RESULTS

Multimodal retinal imaging was performed in 11 eyes with acute retinal vascular obstruction. While 7 eyes demonstrated obvious findings of retinal vein obstruction (5 with central and 2 with hemicentral retinal vein occlusion), 4 eyes were unremarkable at presentation. En face OCT analysis demonstrated a spectrum of perivenular PAMM illustrating a fern-like pattern with sparing of the periarteriolar area in all cases.

CONCLUSION

En face OCT may illustrate a remarkable perivenular pattern of PAMM in eyes with retinal vascular obstruction even in the absence of significant funduscopic findings. Perivenular PAMM with en face OCT demonstrates a wide spectrum of variation with narrow fern-like perivenular lesions at the mildest end and more diffuse lesions with only periarterial sparing at the most severe end of the spectrum. Arterial hypoperfusion secondary to outflow obstruction from a central retinal vein obstruction appears to be the most common cause of this presentation, although primary arterial hypoperfusion may also be an etiology.

Assessment of ischemia in acute central retinal vein occlusion from inner retinal reflectivity on spectral domain optical coherence tomography

Purpose

To determine the relationship between different spectral domain optical coherence tomography (SD-OCT) signs of retinal ischemia in acute central retinal vein occlusion (CRVO) and whether they predict anterior segment neovascularization (ASNV).

Design

Retrospective, observational study.

Subjects

Thirty-nine consecutive patients with acute CRVO and 12 months of follow-up.

Methods

We graded baseline SD-OCTs for increased reflectivity of the inner retina, loss of definition of inner retinal layers, presence of a prominent middle-limiting membrane (p-MLM) sign, and presence of paracentral acute middle maculopathy (PAMM). Graders were masked with respect to all clinical information.

Results

The intraclass correlation coefficients (ICCs) of grading–regrading by graders 1 and 2 were 0.8104, 95% confidence interval (CI) (0.6686, 0.8956), and 0.7986, 95% CI (0.6475, 0.8892), respectively. The intragrader coefficients of repeatability (COR) for graders 1 and 2 were 0.94 and 0.92, respectively. The ICC of graders 1 compared with 2 was 0.8039, 95% CI (0.6544, 0.8916). The intergrader COR was 0.80. SD-OCT grades of baseline ischemia were not associated with baseline visual acuity (VA), central subfield mean thickness (CSMT), or relative afferent pupillary defect; 12-month VA, CSMT, change in VA, change in CSMT, number of antivascular endothelial growth factor injections or corticosteroid injections, or proportion of eyes developing ASNV. SD-OCT grades of ischemia did not correlate with the proportion of eyes having the p-MLM sign or PAMM. PAMM and p-MLM are milder signs of ischemia than increased reflectivity of the inner retinal layers. Eyes with PAMM can evolve, losing PAMM and gaining the p-MLM sign.

Conclusion

Grading of ischemia from SD-OCT in acute CRVO was repeatable within graders and reproducible across graders for the graders in this study. SD-OCT signs of ischemia are not correlated with each other and do not reliably predict subsequent ASNV. Close monitoring of eyes with acute CRVO continues to be the safest method to avoid missing ASNV and neovascular glaucoma.

MACULAR PERIVENOUS RETINAL WHITENING AND PRESUMED RETINO-CILIARY SPARING IN A RECURRENT CENTRAL RETINAL VEIN OCCLUSION ASSOCIATED WITH THE ANTIPHOSPHOLIPID SYNDROME AND CRYOGLOBULINEMIA

PURPOSE

Macular perivenous retinal whitening results from hypoperfusion-induced ischemia of the middle retina that can occur in central retinal vein occlusion (CRVO). We describe an unusual case of recurrent CRVO with macular perivenous retinal whitening and retino-ciliary venous sparing in the setting of 2 prothrombotic diseases, antiphospholipid syndrome and Type II cryoglobulinemia.

METHODS

A 50-year-old man presented with intermittent loss of vision in his right eye related to a recurrent CRVO. Color photography, optical coherence tomography, and fluorescein angiography were performed and compared with those obtained during a previous CRVO that occurred 6 years earlier in the same eye.

RESULTS

On presentation, visual acuity was hand motion in the right eye, 20/30 in the left eye. Funduscopic examination of the right eye showed vascular tortuosity, scattered retinal hemorrhages, and retinal whitening in the macula. Optical coherence tomography showed hyperreflectivity of the middle layers of the retina that correlated with the areas of retinal whitening. A discrete area of retinal sparing was noted in the superonasal macula that, on fluorescein angiography, corresponded to the distribution of a single retino-ciliary vein. A review of retinal imaging obtained during the patient's previous CRVO showed similar but more subtle findings of retino-ciliary sparing. Laboratory testing revealed antiphospholipid syndrome and Type II cryoglobulinemia. As the patient's CRVO progressed and subsequently stabilized after treatment in the following months, this area of venous sparing remained the only functional, nonischemic retinal tissue in his macula. Presumably, this vein possessed privileged and uncompromised blood flow by circumventing the occluded venous circulation.

CONCLUSION

Macular perivenous retinal whitening should be considered in the differential diagnosis of retinal whitening and occurs in CRVO secondary to hypoperfusion-induced middle retinal ischemia. To our knowledge, this case represents the first description of retino-ciliary venous sparing of the retina in CRVO.

Cotton Wool Spots after Anti-Vascular Endothelial Growth Factor Therapy for Macular Edema Associated with Central Retinal Vein Occlusion

PURPOSE

To report a case series, whereby we encountered a transient increase in retinal cotton wool spots (CWS) following anti-vascular endothelial growth factor (anti-VEGF) therapy for the treatment of macular edema secondary to central retinal vein occlusion (CRVO).

METHODS

Eighteen eyes were treated with intravitreal aflibercept (IVA), and 5 were treated with intravitreal ranibizumab (IVR). Fundus photographs obtained 1 month after initial IVA or IVR injections were retrospectively evaluated for the presence of CWS.

RESULTS

Twenty-one (91.3%) patients had the following systemic diseases: hypertension, diabetes mellitus without retinopathy, dyslipidemia, or chronic renal failure requiring dialysis. One month after treatment, reduced macular edema was observed in 21 (91.3%) eyes. Initial injections facilitated complete resolution in 14 eyes, and CWS gradually became fainter with additional injections.

CONCLUSION

Some eyes with CRVO-related macular edema can show a transient increase in CWS after initial anti-VEGF therapy; however, macular edema, retinal hemorrhage, and visual acuity were improved in almost every case.

Optical Coherence Tomography Angiography and En Face Optical Coherence Tomography Features of Paracentral Acute Middle Maculopathy

PURPOSE

To characterize the optical coherence tomography (OCT) angiography, en face OCT, and microperimetry features of paracentral acute middle maculopathy in both the acute phase and after resolution, and to propose a classification of distinct subtypes of this entity.

DESIGN

Retrospective observational case series.

METHODS

Clinical histories, high-resolution digital color imaging, spectral-domain OCT images, fluorescein angiography, OCT angiography images, and en face OCT images of 16 patients with paracentral acute middle maculopathy were evaluated. Microperimetry was available in 6 patients.

RESULTS

The most common referring diagnoses were isolated branch retinal arterial occlusion (5/16), combined central retinal vein and cilioretinal artery occlusion (4/16), and isolated central retinal vein occlusion (4/16). All patients demonstrated hyperreflective plaque-like lesions at the level of the inner nuclear layer on spectral-domain OCT, with no fluorescein angiographic correlate. OCT angiography demonstrated variable areas of capillary dropout within the superficial and deep retinal capillary plexi in these areas. En face OCT highlighted confluent areas of middle retina hyperreflectivity corresponding to these lesions. Three distinct en face OCT patterns were observed: arteriolar, fern-like, and globular. Microperimetry demonstrated relative scotomas mapping to the area of middle retinal hyperreflectivity seen on en face OCT.

CONCLUSIONS

Paracentral acute middle maculopathy may be best evaluated with the use of en face OCT imaging, which corresponds to subjective and objective visual field defects. En face OCT appearance may be used to classify paracentral acute maculopathy into distinct subtypes.

Evidence for an enduring ischaemic penumbra following central retinal artery occlusion, with implications for fibrinolytic therapy

The rationale behind hyperacute fibrinolytic therapy for cerebral and retinal arterial occlusion is to rescue ischaemic cells from irreversible damage through timely restitution of tissue perfusion. In cerebral stroke, an anoxic tissue compartment (the "infarct core") is surrounded by a hypoxic compartment (the "ischaemic penumbra"). The latter comprises electrically-silent neurons that undergo delayed apoptotic cell death within 1-6 h unless salvaged by arterial recanalisation. Establishment of an equivalent hypoxic compartment within the inner retina following central retinal artery occlusion (CRAO) isn't widely acknowledged. During experimental CRAO, electroretinography reveals 3 oxygenation-based tissue compartments (anoxic, hypoxic and normoxic) that contribute 32%, 27% and 41% respectively to the pre-occlusion b-wave amplitude. Thus, once the anoxia survival time (≈2 h) expires, the contribution from the infarcted posterior retina is irreversibly extinguished, but electrical activity continues in the normoxic periphery. Inbetween these compartments, an annular hypoxic zone (the "penumbra obscura") endures in a structurally-intact but functionally-impaired state until retinal reperfusion allows rapid recovery from electrical silence. Clinically, residual circulation of sufficient volume flow rate generates the heterogeneous fundus picture of "partial" CRAO. Persistent retinal venous hypoxaemia signifies maximal extraction of oxygen by an enduring "polar penumbra" that permeates or largely replaces the infarct core. On retinal reperfusion some days later, the retinal venous oxygen saturation reverts to normal and vision improves. Thus, penumbral inner retina, marginally oxygenated by the choroid or by residual circulation, isn't at risk of delayed apoptotic infarction (unlike hypoxic cerebral cortex). Emergency fibrinolytic intervention is inappropriate, therefore, once the duration of CRAO exceeds 2 h.

Optical coherence tomography predicts visual outcome in acute central retinal vein occlusion

PURPOSE

To investigate the clinical features of central retinal vein occlusion (CRVO) in relation to the presence of a prominent middle limiting membrane (p-MLM) sign on presenting optical coherence tomography, which may suggest macular ischemia and poor visual outcome.

METHODS

Fifty consecutive eyes with acute CRVO of <1 month of symptom duration before presentation were retrospectively reviewed. A hyperreflective line located in the outer plexiform layer (p-MLM) in optical coherence tomography was used as a sign of acute ischemia. Cases with p-MLM were grouped and compared with the group of eyes with no p-MLM sign (non-MLM group) for clinical features including visual acuities, central fovea thickness, and CRVO types.

RESULTS

Among the 50 eyes, 14 (28%) eyes showed a p-MLM sign, 21 (42%) eyes did not, and others had equivocal findings. Eyes with p-MLM sign presented worse initial and final best-corrected visual acuity compared with the non-MLM group (1.10 ± 0.72 vs. 0.47 ± 0.49 logMAR in the initial best-corrected visual acuity, P = 0.007; and 1.08 ± 0.86 vs. 0.32 ± 0.41 logMAR in the final best-corrected visual acuity, P = 0.044) in patients with a follow-up duration of 6 months or longer. The p-MLM group eyes showed a higher tendency toward being classified as ischemic type CRVO (57.1 vs. 4.8%, P = 0.001).

CONCLUSION

Central retinal vein occlusion showing p-MLM on optical coherence tomography had worse visual outcome with higher incidence of being classified into ischemic type CRVO.

Paracentral acute middle maculopathy in nonischemic central retinal vein occlusion

PURPOSE

To better characterize a novel spectral-domain optical coherence tomography (OCT) presentation, termed paracentral acute middle maculopathy, to describe this finding in patients with nonischemic central retinal vein occlusion (CRVO), and to support a proposed pathogenesis of intermediate and deep retinal capillary ischemia.

DESIGN

Retrospective observational case series.

METHODS

Clinical histories, high-resolution digital color imaging, red-free photography, fluorescein angiography, near-infrared reflectance, and spectral-domain OCT images of 484 patients with acute CRVO from 2 centers were evaluated for the presence of coexisting paracentral acute middle maculopathy.

RESULTS

Of 484 patients diagnosed with CRVO, 25 (5.2%) demonstrated evidence of concurrent paracentral acute middle maculopathy. Patients averaged 51 years of age and presented with complaints of paracentral scotomas. All patients demonstrated hyper-reflective plaquelike lesions at the level of the inner nuclear layer by spectral-domain OCT and showed corresponding dark-gray lesions on near-infrared reflectance and perivenular deep retinal whitening on color fundus photography. There was no fluorescein angiographic correlate to these lesions. On follow-up spectral-domain OCT imaging, the lesions had resolved into areas of inner nuclear layer atrophy with persistence of scotomas.

CONCLUSIONS

Paracentral acute middle maculopathy refers to characteristic hyper-reflective spectral-domain OCT lesions involving the middle layers of the retina at the level of the inner nuclear layer that may develop in response to ischemia of the intermediate and deep capillary plexuses. This series is the largest to describe this spectral-domain OCT finding to date, and it is the first to associate it with nonischemic CRVO.

Krogh cylinders in retinal development, panretinal hypoperfusion and diabetic retinopathy

The volume of cells that a length of capillary supplies with O(2) is called a Krogh cylinder. This geometric 'tissue unit' was named after the Danish zoophysiologist and Nobel laureate August Krogh who made important discoveries in the fields of external and internal respiration in the first half of the last century. Krogh's ideas concerning tissue O(2) distribution can be extrapolated to retinal oxygenation by larger vessels (including arterioles, arteries and even veins) and by vessel groups within higher-order 'microvascular units' (including the choroid). During retinal development, for example, the difference in pO(2) levels within arteries and capillaries determines Krogh cylinders of different radius and establishes the periarterial capillary-free zone of His. The O(2) supply to the venous end of a tissue unit may be compromised during periods of reduced perfusion, increased O(2) consumption or hypoxaemia, resulting in an 'anoxic corner' of the Krogh cylinder. A funnel of hypometabolic (and therefore hypoxia-tolerant) cells will likely intervene between the necrotic cells and unaffected cells located closer to the O(2) source. Macular perivenular whitening heralds anoxic corners and/or hypoxic funnels owing to hypoperfusion within second-order microvascular units. In eyes with extensive retinal capillary closure from diabetes, Krogh cylinders surround the medium-sized arteries and veins that form arteriovenous shunts while traversing the midperipheral retina. These isolated tissue units incorporate an outer sheath of hypoxic cells within which vascular endothelial growth factor is upregulated. This 'angiogenic sheath' expands following retinal detachment; it corresponds to the hypoxia-tolerant funnel within capillary-based tissue units and to the cerebral penumbra after stroke.

Central retinal vein occlusion with cilioretinal infarction from branch flow exclusion and choroidal arterial steal

PURPOSE

The first definitive study of retinal vein occlusion complicated by infarction within the territory of one or more cilioretinal arteries was published in 1976. Many individual cases and further case series have been reported in the interim, but the nature of the interrelationship is still under debate.

METHODS

A review was undertaken of the relevant clinical and fundus fluorescein angiographic characteristics of this combined retinal vascular disorder together with the pathophysiological mechanisms currently presented in the literature to explain their association. Scientific publications up to 2008 were evaluated by one of the authors of the original report.

RESULTS

There are broad similarities between publications in their descriptions of the clinical features, but significant differences of detail and interpretation are also evident. Most of the mechanisms so far proposed to account for cilioretinal infarction after central or hemisphere retinal vein occlusion do not withstand critical scrutiny. Two related hypotheses are expounded that appear to satisfactorily elucidate this interrelationship -- branch flow exclusion and branch flow diversion (otherwise termed "choroidal arterial steal").

CONCLUSION

In eyes with a cilioretinal supply, the probability that cilioretinal infarction will complicate retinal vein occlusion increases with increasing severity of venous obstruction and the more distally the cilioretinal artery arises from the posterior ciliary arterial tree. A distal branch point also facilitates observation of dye front reciprocation within the artery. Indicators of the degree of venous obstruction that may be necessary to instigate cilioretinal infarction include very prolonged dye transit times in the central retinal circulation, exaggerated venous cyanosis and tortuosity, perivenous cotton-wool sentinels, and macular perivenular whitening.

Retinal pathology of pediatric cerebral malaria in Malawi

Introduction

The causes of coma and death in cerebral malaria remain unknown. Malarial retinopathy has been identified as an important clinical sign in the diagnosis and prognosis of cerebral malaria. As part of a larger autopsy study to determine causes of death in children with coma presenting to hospital in Blantyre, Malawi, who were fully evaluated clinically prior to death, we examined the histopathology of eyes of patients who died and underwent autopsy.

Methodology/Principal Findings

Children with coma were admitted to the pediatric research ward, classified according to clinical definitions as having cerebral malaria or another cause of coma, evaluated and treated. The eyes were examined by direct and indirect ophthalmoscopy. If a child died and permission was given, a standardized autopsy was carried out. The patient was then assigned an actual cause of death according to the autopsy findings. The eyes were examined pathologically for hemorrhages, cystoid macular edema, parasite sequestration and thrombi. They were stained immunohistochemically for fibrin and CD61 to identify the components of thrombi, β-amyloid precursor protein to detect axonal damage, for fibrinogen to identify vascular leakage and for glial fibrillary acidic protein to detect gliosis. Sixty-four eyes from 64 patients were examined: 35 with cerebral malaria and 29 with comas of other causes. Cerebral malaria was distinguished by sequestration of parasitized erythrocytes, the presence and severity of retinal hemorrhages, the presence of cystoid macular edema, the occurrence and number of fibrin-platelet thrombi, the presence and amount of axonal damage and vascular leakage.

Conclusions/Significance

We found significant differences in retinal histopathology between patients who died of cerebral malaria and those with other diagnoses. These histopathological findings offer insights into the etiology of malarial retinopathy and provide a pathological basis for recently described retinal capillary non-perfusion in children with malarial retinopathy. Because of the similarities between the retina and the brain it also suggests mechanisms that may contribute to coma and death in cerebral malaria.

Central retinal vein occlusion associated with cilioretinal artery occlusion

PURPOSE

To describe the clinical characteristics and pathogenesis of central retinal vein occlusion (CRVO) associated with cilioretinal artery occlusion (CLRAO).

METHODS

The study included 38 patients (38 eyes) who had CRVO associated with CLRAO and were seen in our clinic from 1974 to 1999. At their first visit to our clinic, all patients provided a detailed ophthalmic and medical history and underwent comprehensive ophthalmic evaluation, color fundus photography, and fluorescein fundus angiography. At each follow-up visit, the same ophthalmic evaluations were performed, except for fluorescein fundus angiography.

RESULTS

Of 38 eyes, 30 had nonischemic CRVO, 5 had ischemic CRVO, and 3 had nonischemic hemi-CRVO. Patients with nonischemic CRVO were significantly younger (mean age +/- SD: 45.3 +/- 16.0 years) than those with ischemic CRVO (72.3 +/- 9.2 years; P = 0.001) and those with nonischemic hemi-CRVO (64.7 +/- 7.5 years; P = 0.018). At least one third of the patients gave a definite history of episode(s) of transient visual blurring before the onset of constant blurred vision. Initially, the ophthalmoscopic and fluorescein angiographic findings were similar to those seen in CRVO and hemi-CRVO, except that all these eyes had retinal infarct in the distribution of the cilioretinal artery; its size and site varied widely. Fluorescein angiography typically showed only transient hemodynamic block and not the typical CLRAO. During follow-up, visual acuity improved markedly in nonischemic CRVO (P < 0.001) and nonischemic hemi-CRVO but deteriorated in ischemic CRVO. Retinopathy resolved spontaneously in 22 eyes with nonischemic CRVO (mean duration +/- SD: 42.0 +/- 101.0 months), in 2 eyes with ischemic CRVO (15.4 +/- 4.5 months), and in 1 eye with nonischemic hemi-CRVO. Retinociliary collaterals developed in 30% of eyes with nonischemic CRVO, in 40% of eyes with ischemic CRVO, and in 66% of eyes with nonischemic hemi-CRVO.

CONCLUSION

CRVO associated with CLRAO constitutes a distinct clinical entity. The pathogenesis of CLRAO in CRVO is due to transient hemodynamic blockage of the cilioretinal artery caused by a sudden sharp rise in intraluminal pressure in the retinal capillary bed (due to CRVO) above the level of that in the cilioretinal artery.

[Therapy refractory blepharoconjunctivitis in a 90 year old patient]

Sebaceous gland carcinoma can clinically mimic benign conditions such as chalazion and blepharoconjunctivitis. This carcinoma should be histologically excluded for every unilateral, recalcitrant chalazion and every unilateral, therapy refractory blepharitis. Autosomal dominant Muir-Torre syndrome should be considered in patients who develop sebaceous gland carcinoma of the ocular adnexa. In this case, the sebaceous gland carcinoma is combined with visceral carcinoma.

Systolodiastolic variations of blood flow during central retinal vein occlusion: exploration by dynamic angiography

BACKGROUND/AIM

In patients with acute central retinal vein occlusion (CRVO), dynamic angiography may reveal the presence of pulsatile flow (termed here pulsatile venular outflow, PVO) within first order veins (that is, the large veins). The main goal of this study was to investigate the mechanism underlying PVO.

METHODS

10 patients with CRVO and PVO were included. Quantitative and qualitative analysis of venous flow on dynamic angiograms allowed the correlation, temporally, of second and first order vein flow on the one hand, and venous flow and systolic cycle on the other.

RESULTS

Analysis of the time-velocity curve showed that (1) the onset of arterial systole preceded the onset of PVO by less than 0.08 seconds (n = 5); (2) PVO onset was simultaneous to the time of onset of minimal flow (Vmin) in first order veins (n = 10); (3) the time of onset of maximal flow (Vmax) in first order veins occurred 0.20-0.44 seconds after the onset of PVO (n = 6).

CONCLUSIONS

During CRVO with severe reduction in blood flow, the presence of PVO is the result of the existence of a distinct haemodynamic regimen in first and second order veins. These data support the hypothesis that second order veins flow is synchronous with the arterial flow, while the delayed peak flow in first order veins may reflect the consequences of the delayed IOP curve and/or of intermittent venous compression.

Visual outcomes in children in Malawi following retinopathy of severe malaria

AIM

To investigate whether retinal changes in children with severe malaria affect visual acuity 1 month after systemic recovery.

METHODS

All children with severe malaria admitted to a research ward in Malawi during one malaria season were examined by direct and indirect ophthalmoscopy. Visual acuity was tested in those attending follow up by Cardiff cards, Sheridan-Gardiner single letters, or Snellen chart.

RESULTS

96 (68%) children attended follow up, of whom 83 (86%) had visual acuity measured. Cardiff cards were used in 47 (57%) children, and Sheridan-Gardiner letters or Snellen chart in 29 (35%). There was no significant difference in the mean logMAR visual acuity between groups with or without macular whitening (0.14 versus 0.16, p = 0.55). There was no trend for worse visual acuity with increasing severity of macular whitening (p = 0.52) including patients in whom the fovea was involved (p = 0.32). Six (4.2%) children had cortical blindness after cerebral malaria, and all six had other neurological sequelae. Ophthalmoscopy during the acute illness revealed no abnormalities in four of these children.

CONCLUSION

Retinal changes in severe malaria, in particular macular whitening, do not appear to affect visual acuity at 1 month. This supports the hypothesis that retinal whitening is due to reversible intracellular oedema in response to relative hypoxia, caused by sequestered erythrocytes infected by Plasmodium falciparum. Impaired visual functioning after cerebral malaria is not attributable to retinal changes and appears to be a cortical phenomenon.