Clinical Features of Combined Central Retinal Artery and Vein Occlusion

Normalized Reflectivity of Middle Limiting Membrane on SD-OCT: A Measure of Acute Ischemia in CRVO

PURPOSE

To validate the quantification of the prominent middle limiting membrane (PMLM) sign, a marker of mild-to-moderate acute ischemic damage on optical coherence tomography (OCT), by measuring middle limiting membrane (MLM) reflectivity in patients with central retinal vein occlusion (CRVO) and to investigate the prognostic impact of this measure.

METHODS

Spectral Domain (SD)-OCT B-scans of 30 patients with CRVO, either sole CRVO or combined central retinal artery and vein occlusion (CCRAVO), were analyzed retrospectively and graded as PMLM present or absent. Normalized MLM reflectivity was calculated as a ratio of the maximum reflectivity within a MLM target layer and the average reflectivity of the retinal pigment epithelium (RPE).

RESULTS

Discrimination between OCT B-scans graded as PMLM present or absent based on ROC analysis was far superior with normalized MLM reflectivity (AUC >0.90) than using MLM reflectivity without normalization (AUC = 0.70). Normalized MLM reflectivity was significantly higher in study eyes than healthy fellow eyes as well as in patients with CCRAVO versus sole CRVO. Although normalized MLM reflectivity correlated significantly with baseline and outcome BCVA, we found no significant difference comparing patients with ischemic CRVO versus non-ischemic CRVO.

CONCLUSIONS

Quantifying MLM reflectivity requires normalization due to shadowing, which is usually caused by retinal haemorrhages in CRVO. RPE reflectivity proved to be a suitable reference layer. Greater normalized MLM reflectivity as a measure of mild-to-moderate acute ischemic damage indicated a worse prognosis regarding visual function in CRVO, however, it allows no risk assessment regarding the development of capillary non-perfusion or anterior segment neovascularization.

Update on central retinal artery occlusion

The medical condition referred to as "central retinal artery occlusion" (CRAO) was first documented by Albrecht von Graefe in 1859. Subsequently, CRAO has consistently been identified as a serious medical condition that leads to substantial visual impairment. Furthermore, it is correlated with vascular complications that have the potential to affect crucial organs such as the brain and heart. A considerable amount of research has been extensively published on the various aspects of this topic, which is marked by notable debates and misconceptions, especially regarding its management and outcomes. The primary aim of this review article is to analyze the latest developments in the understanding of CRAO, which includes its causes, techniques for retinal imaging, systemic evaluation, and therapeutic strategies, such as vitrectomy. This review article offers readers a comprehensive learning experience to gain knowledge on the fundamental principles and recent advancements in CRAO.

Exploring laser-induced acute and chronic retinal vein occlusion mouse models: Development, temporal in vivo imaging, and application perspectives

Photodynamic venous occlusion is a commonly accepted method for establishing mouse models of retinal vein occlusion (RVO). However, existing model parameters do not distinguish between acute and chronic RVO subtypes. Large variations in laser energy seem to correlate with fluctuating retinopathy severity and high rates of venous recanalization during the acute phase, along with the variable levels of retinal perfusion during the chronic phase. After optimizing the modeling procedure and defining success and exclusion criteria, laser energy groups of 80mW, 100mW, and 120mW were established. Multimodal imaging confirmed that higher energy levels increased the incidence of retinal cystoid edema and intraretinal hemorrhage, exacerbated the severity of exudative retinal detachment, and reduced the venous recanalization rate. For the acute model, 100mW was considered an appropriate parameter for balancing moderate retinopathy and venous recanalization. Continuous imaging follow-up revealed that day 1 after RVO was the optimal observation point for peaking of retinal thickness and intensive occurrence of retinal cystic edema and intraretinal hemorrhage. After excluding the influence of venous recanalization on retinal thickness, acute retinal edema demonstrated a positive response to standard anti-vascular endothelial growth factor therapy, validating the clinical relevance of the acute RVO model for further study in pathogenic mechanisms and therapeutic efficacy. For the chronic model, the 120mW parameter with the lowest venous recanalization rate was applied, accompanied by an increase in both photocoagulation shots and range to ensure sustained vein occlusion. Imaging follow-up clarified non-ischemic retinopathy characterized by tortuosity and dilation of the distal end, branches, and adjacent veins of the occluded vein. These morphological changes are quantifiable and could be combined with electrophysiological functional assessment for treatment effectiveness evaluation. Moreover, the stable state of venous occlusion may facilitate investigations into response and compensation mechanisms under conditions of chronic retinal hypoperfusion.

COMBINED CENTRAL RETINAL VASCULAR OCCLUSION AS THE PRESENTING FEATURE IN β-THALASSEMIA WITH IRON DEFICIENCY ANEMIA

PURPOSE

To report a case of β-thalassemia trait with iron deficiency anemia presenting as a combined central retinal vein and artery occlusion.

METHODS

Case report. A 22-year-old woman presented with sudden-onset blurry vision in the left eye of 3-day duration.

RESULTS

Best-corrected visual acuity was 20/20 and 20/1000 in right and left eyes, respectively. Fundus examination of the left eye revealed optic disk edema, macular whitening with a cherry-red spot, markedly dilated and tortuous retinal veins, and hemorrhages both around the disk and extending into the macula and the periphery. Fundus fluorescein angiography showed delayed filling of retinal vasculature, dilated and tortuous retinal veins, and blocked fluorescence around and beyond the optic disk. Optical coherence tomography scan at presentation showed hyperreflective inner retinal layers with neurosensory detachment. Optical coherence tomography angiography showed that the vessel densities of superficial and deep capillary plexus were remarkably reduced. A diagnosis of β-thalassemia trait combined with iron deficiency anemia was made after hematologic workup. The patient was treated with a course of oral iron supplements, vasodilator (compound Xueshuantong), inhalation of a mixture of 5% carbon dioxide and 95% oxygen, and a nutritional agent (compound anisoine). Six months later, her visual acuity improved to 20/60 in the left eye with complete resolution of all clinical signs.

CONCLUSION

Combined central retinal vein and artery occlusion is a rare emergency leading to acute vision loss and can manifest in patients with β-thalassemia trait with iron deficiency anemia. Prompt diagnosis and early management is important to treat underlying systemic disorders and to prevent occurrence of a similar episode in fellow eye.

Simultaneous unilateral central retinal vein occlusion and branch retinal artery occlusion after Coronavirus Disease 2019 (COVID-19) mRNA vaccine

A 51-year-old non-obese woman presented with a one-week history of progressive blurry vision within the inferior visual field of her left eye. Her only relevant past medical history was long-standing hypothyroidism and recent vaccination against Coronavirus Disease 2019 (COVID-19) with an mRNA vaccine 12 days before the onset of symptoms. At examination, the anterior segment was unremarkable, but the retinal fundus revealed a central retinal vein occlusion associated with a branch retinal artery occlusion of the superior temporal branch in her left eye. Ancillary tests to rule out thrombophilia, hyperviscosity, hypercoagulability, or inflammation were negative. Ultrasound tests were also negative for a cardiac or carotid origin of the branch retinal artery occlusion. At two-month follow-up, no new retinal vascular occlusive events were observed. Although the best-corrected visual acuity at presentation was 8/10 in the left eye, the final best-corrected visual acuity remained 3/10.

Combined central retinal artery and vein occlusion following trabeculectomy

Retinal vascular events may occur as rare complications of glaucoma procedures due to various factors, including exacerbation of ischemia in patients with pre-existing vascular comorbidities, toxic effect of mitomycin-C, and decompression retinopathy. We present the case of a 47-year-old hypertensive male who underwent trabeculectomy for advanced glaucoma in his right eye. At 3 weeks postoperatively, he presented with a drop in visual acuity to light perception with a spike in intraocular pressure. On examination, there was increased bleb vascularity as well as rubeosis. Fundoscopy revealed findings consistent with both central retinal artery occlusion and central retinal vein occlusion. Combined central retinal artery and vein occlusion is a rare retinal vascular condition. Neovascular glaucoma can occur as a sequelae of the ischemic process in the retina. Despite treatment, there is a poor visual prognosis, with the affected eye usually becoming blind from optic atrophy and neovascularization.

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.

[A case of blindness caused by mucocele of frontal sinus]

A case of blindness caused by frontal sinus mucocele was reported. The patient presented with pain and swelling in his left eye and decreased visual acuity with only light sensation for 3 days. Orbital imaging examination suggested a mass of communication in the left frontal sinus and the upper quadrant of left orbit, which was considered as a mucinous cyst involving the left superior orbital wall, surrounding the left lacrimal gland, pushing down the left superior rectus muscle, squeezing the left eyeball and protruding forward and downward. The patient was diagnosed with a left frontal sinus cyst with infection and a left orbital subperiosteal abscess. After admission, frontal sinus drainage was performed urgently, but the vision loss in the left eye was not recovered.

Population-Based Incidence of Ocular Neovascularization Following Central Retinal Artery Occlusion in Olmsted County, Minnesota

Purpose

To determine the population-based incidence of ocular neovascularization (NV) following central retinal artery occlusion (CRAO) and systemic risk factors associated with its development.

Methods

Diagnosis of CRAO between January 1, 1976, and September 9, 2016, was identified using the Rochester Epidemiology Project, a medical records linkage system for all medical care provided to residents of Olmsted County, Minnesota. Records were reviewed to confirm the diagnosis of CRAO, and data were collected on ocular NV and associated systemic diseases.

Results

There were 89 patients with CRAO. Subsequent ocular neovascularization developed in 14 (16%) patients. Neovascularization of the iris (NVI) was present in 9/14 (64%) of these patients, neovascularization of the angle (NVA) in 10/14 (71%), neovascularization of the disc (NVD) in 2/14 (14%), and neovascularization elsewhere (NVE) in 1/14 (7%). Of these 14 patients with NV, 9 (64%) developed neovascular glaucoma (NVG). The mean time from CRAO diagnosis to NV was 82 days (range 22 to 268 days). Excluding the patients with proliferative diabetic retinopathy or CRAO caused by CRVO, the mean time to NV diagnosis was 80 days and the shortest time to NV diagnosis was 22 days. Diabetes mellitus was present in 64% of those with NV compared to 23% of those without NV (P = 0.003).

Conclusion

The population-based incidence of ocular neovascularization following CRAO is 16% and developed within 2 months in half the cohort. Patients with diabetes mellitus are at increased risk for NV complications.