Optic disk and retinal nerve fiber layer damage after transient central retinal artery occlusion: an experimental study in rhesus monkeys

Efficacy and safety of ultrasound combined with microbubbles for treating retinal artery occlusion in rats

Retinal artery occlusion (RAO) is an eye emergency that results in severe and permanent visual impairment. The effectiveness of conventional treatment on retinal artery recanalization and vision improvement is uncertain. Ultrasound combined with microbubbles (USMB) technology is a minimally invasive transvascular drug delivery technique that has been used to investigate the treatment of stroke, myocardial infarction ，and obstructive vascular disease. The aim of this study was to investigate the efficacy and safety of USMB in the treatment of RAO. RAO model was induced by photochemical thrombosis. Normal rat eyes were treated with ultrasound at different mechanical index (MI) of 0.2,0.4 and 0.8, to explore its safety. RAO rats were randomly divided into RAO group, RAO + USMB group and RAO + US (Ultrasound) group to explore the effectiveness of the USMB in the treatment of RAO. A set of relevant ophthalmic in vivo imaging techniques was used to explore the natural history of RAO model rats while assessing tolerance and efficacy to USMB treatment. We found that blocked retinal arteries recanalized within 4-24 h in the RAO model. Retinal edema peaks within 4-24 h and resolves within 3-7 days. Blood flow density (BFD) began to recover 4 h after model induction. USMB did not cause irreversible retinal damage when the MI was below 0.4. Treatment with USMB at an MI of 0.2 significantly reduced retinal edema in RAO rats 1 day after model induction and prevented further retinal atrophy. In addition, USMB significantly increased BFD in RAO rats within 4 h and promoted the recovery of visual function. USMB can be a safe and effective treatment for RAO with protective effects on the neuroretina.

Visual outcomes of central retinal artery occlusion: Exploring treatment strategies beyond the conventional time window

BACKGROUNDS/AIMS

Central retinal artery occlusion (CRAO) is a vision-devastating emergency. However, widely-acknowledged treatment consensus is lacking and prehospital delays commonly occur. Hence, we aimed to investigate the visual outcomes of conservative treatments (CT), local intra-arterial fibrinolysis (LIF) and hyperbaric oxygen (HBO) therapy for non-arteritic CRAO (NA-CRAO) patients beyond the conventional time window.

METHODS

This retrospective comparative study included 99 NA-CRAO patients followed up for over 6 months. The subjects were divided into three groups: the CT (50 patients), LIF (10 patients) and HBO group (39 patients). The primary endpoint was the best-corrected visual acuity (BCVA) change at 6 months compared to baseline. The secondary endpoint was the improvement in BCVA at 1 year and final visits.

RESULTS

No heterogeneity regarding demographics was identified. However, the HBO group had a more extended time-to-treatment period (median 6.0 days) and more advanced-stage CRAO cases (41 % stage III) than the CT (median 4.0 days, 14 % stage III) and LIF (median 0.6 days, 20 % stage III) groups. Despite this, the HBO group exhibited a significantly greater BCVA and a higher proportion of patients achieving significant vision improvement than those in the CT group at 6-, 12-month and final exams (51.3 % vs. 24.0 %, P < 0.05). The LIF appeared to improve outcomes more than CT over time without significance.

CONCLUSION

Our study provided a concurrent comparison across 3 approaches and demonstrated that HBO therapy beyond the time window remained more effective in improving vision than CT alone for NA-CRAO patients, which had not been proposed by prior studies.

Optical coherence tomography: implications for neurology

PURPOSE OF REVIEW

This article explores the role of optical coherence tomography (OCT) in neurology practice, particularly in diagnosing and monitoring conditions such as papilledema, optic neuritis, and retinal artery occlusion. OCT has been increasingly utilized as a noninvasive and effective tool for detecting and monitoring neuroaxonal damage in the visual pathway, which is important for early intervention and improved patient outcomes across a variety of neurologic conditions.

RECENT FINDINGS

OCT as an imaging modality continues to demonstrate its utility in quantifying optic nerve and retinal changes reflecting neuroaxonal injury, including, peripapillary retinal nerve fiber layer (pRNFL) thickness and macular ganglion cell layer thickness (or volume). This review focuses on recent evidence regarding the utilization of this modality in diagnosing, monitoring, and quantifying treatment responses in patients with papilledema, optic neuritis, and retinal artery occlusion. Advances in OCT technology, including deep learning algorithms, continue to enhance the diagnostic accuracy and predictive capabilities in the field of neuro-ophthalmology.

SUMMARY

In recent years, OCT has become an essential tool in neuro-ophthalmic assessment, offering precise structural and anatomical assessments that support diagnosis, treatment planning, and monitoring of conditions affecting the visual pathway. Ongoing advances in OCT technology are expected to further enhance its clinical utility.

Embolization of Ophthalmic Artery Induced By Ear Hyaluronic Acid Injection

Ear filling injection of hyaluronic acid (HA) is emerging as a new application of HA filling in clinical practice. However, its risks and complications have not been sufficiently investigated. Herein, we report a case of 25-year-old female with embolization of ophthalmic artery, a severe complication caused by ear filling of HA. Injection of HA at the triangular fossa immediately induced amaurosis and dizziness, and complete loss of light sensation in the right eye 10 min after injection. These symptoms did not resolve after emergency treatment, and she was sent to our hospital for treatment. A diagnosis of central retinal arterial occlusion (CRAO) was made, for which the patient received intravascular interventional therapy as an emergency treatment. Following surgery, the patient received a multifaceted treatment approach to promote nerve health, improve blood circulation, reduce edema, and enhance oxygen delivery through hyperbaric oxygen therapy. This treatment regimen restored light perception and resolved mottled skin discoloration. This case report expands our understanding of the potential mechanisms and anatomical factors involved in embolization associated with ear filler injections. Furthermore, it highlights the importance of prompt intervention, providing valuable insights for reducing the complication rate and improving patient outcomes following such procedures.Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Retina-Brain Homology: The Correlation Between Ophthalmic or Retinal Artery Occlusion and Ischemic Stroke

The retina's similar structure and function to the brain make it a unique visual "window" for studying cerebral disorders. Ophthalmic artery occlusion (OAO) or retinal artery occlusion (RAO) is a severe ophthalmic emergency that significantly affects visual acuity. Studies have demonstrated that patients with OAO or RAO face a notably higher risk of future acute ischemic stroke (AIS). However, ophthalmologists often overlook multidisciplinary approach involving the neurologist, to evaluate the risk of AIS and devise clinical treatment strategies for patients with OAO or RAO. Unlike the successful use of thrombolysis in AIS, the application of thrombolysis for OAO or RAO remains limited and controversial due to insufficient reliable evidence. In this review, we aim to summarize the anatomical and functional connections between the retina and the brain, and the clinical connection between OAO or RAO and AIS, compare and review recent advances in the effectiveness and safety of intravenous and intra-arterial thrombolysis therapy in patients with OAO or RAO, and discuss future research directions for OAO or RAO. Our goal is to advance the development of multidisciplinary diagnosis and treatment strategies for the disease, as well as to establish expedited pathways or thrombolysis guidelines for vascular intervention.

Marginal Full Thickness Blepharotomy for Management of Orbital Compartment Syndrome

PURPOSE

To assess the utility of a marginal full thickness blepharotomy (MFTB) for the treatment of orbital compartment syndrome.

METHODS

An experimental study design employing a cadaver model for orbital compartment syndrome was used to assess the efficacy of an MFTB. Elevated orbital compartment pressures were created in 12 orbits of 6 fresh cadaver heads. Intraocular pressure, as an analog of orbital pressure, was measured before and after inferior and superior MFTBs were performed. Statistical analysis was performed on the collected data to assess the efficacy of the procedure.

RESULTS

Both procedures were found to significantly lower the orbital compartment pressure. MFTB of the inferior lateral eyelid decreased orbital compartment pressure by an average of 62.2 mm Hg (95% CI, 56.9-67.5). MFTB of the superior lateral eyelid following MFTB of the inferior lateral eyelid decreased the orbital compartment pressure by an additional average of 10.3 mm Hg (total average reduction of 72.5 mm Hg; 95% CI, 68.1-76.9).

CONCLUSIONS

Orbital compartment syndrome is a time-sensitive vision-threatening emergency that requires prompt diagnosis and intervention to prevent irreversible vision loss. The authors describe the MTFB, a simple one-step procedure that when performed correctly results in a significant decrease in orbital compartment pressure, making it a viable option when canthotomy and cantholysis fails or is unable to be performed.

A Case Series of Retinal Artery Occlusion: When Time Is of the Essence

This case series discusses the presentation, etiologies, and management of retinal artery occlusions in three patients. The first case was diagnosed as right eye central retinal artery occlusion (CRAO) secondary to a hypercoagulable state as the patient had been newly diagnosed with chronic myeloid leukemia. The second case had right branch retinal artery occlusion (RAO) secondary to a thromboembolic event following a percutaneous transluminal coronary angioplasty procedure. The third case involved a right eye CRAO secondary to vasospastic syndrome. The first case had good visual recovery as the patient presented to us within four hours of the onset. In contrast, the second and third cases presented after seven to eight hours, resulting in poor visual recovery. Though several measures have been devised to reverse the occlusion, the final visual prognosis still depends on the degree of occlusion and the time of presentation, as late presentation is usually associated with irreversible visual loss. Detection of RAO may require a multidisciplinary team approach, and proper and timely management may reverse the ischemic state of the retina.

Improved visual outcomes of central retinal artery occlusion with local intra-arterial fibrinolysis beyond the conventional time window

Local intra-arterial fibrinolysis (LIF) is a promising therapeutic option for CRAO. However, the narrow time window of 6 h has greatly limited the application of LIF. In this study, we explored the efficacy of LIF beyond the conventional time windows and compared the result with conservative therapy. This prospective study included 179 CRAO patients with baseline visual acuity (VA) ≤ 20/400 treated at Renmin Hospital of Wuhan University. The mean time from vision loss to presentation was 5.5 days. 58 patients received conventional standard therapy (CST) alone.121 patients underwent LIF. Main outcome was VA improvement ≥ 0.3 logMAR. Secondary outcome was a favorable VA outcome of 20/200 or better. Logistic regressions were performed to identify predictors of visual improvement. 43% patients in the LIF group experienced VA improvement versus 19% with CST (P = 0.002). LIF was associated with 4.0-fold higher likelihood of visual improvement compared to CST (P = 0.001). Poor baseline VA (light perception or no light perception) and shortened prothrombin time (PT) were associated with greater chance of visual improvement with LIF. However, LIF showed no significant advantage over CST for favorable VA outcomes. No major complications occurred. LIF beyond the therapeutic time window improved vision in functionally blind CRAO patients and showed better efficacy when compared with CST. PT may be a potential predictor of visual outcome after LIF. Our findings could complement existing time-based treatment guidelines and potentially allow for personalized decisions on the use of LIF beyond time windows.

BOB-ACG study: Pulse methylprednisolone to prevent bilateral ophthalmologic damage in giant cell arteritis. A multicentre retrospective study with propensity score analysis

INTRODUCTION

Giant cell arteritis (GCA) is complicated in 10 to 20% of cases by permanent visual ischemia (PVI). International guidelines advocate the use of intravenous pulse of methylprednisolone from 250 to 1000mg per day, for three days, followed by oral prednisone at 1mg/kg per day. The aim of this study is to assess whether this strategy significantly reduces the risk of early PVI of the second eye, compared with direct prednisone at 1mg/kg per day.

METHODS

We conducted a multicentre retrospective observational study over the past 15 years in 13 French hospital centres. Inclusion criteria included: new case of GCA; strictly unilateral PVI, prednisone at dose greater than or equal to 0.9mg/kg per day; for the intravenous methylprednisolone (IV-MP) group, total dose between 900 and 5000mg, close follow-up and knowledge of visual status at 1 month of treatment, or earlier, in case of contralateral PVI. The groups were compared on demographic, clinical, biological, iconographic, and therapeutic parameters. Statistical analysis was optimised using propensity scores.

RESULTS

One hundred and sixteen patients were included, 86 in the IV-MP group and 30 in the direct prednisone group. One patient in the direct prednisone group and 13 in the IV-MP group bilateralised, without significant difference between the two strategies (3.3% vs 15.1%). Investigation of the association between IV-MP patients and contralateral PVI through classical logistic regression, matching or stratification on propensity score did not show a significant association. Weighting on propensity score shows a significant association between IV-MP patients and contralateral PVI (OR=12.9 [3.4; 94.3]; P<0.001). Improvement in visual acuity of the initially affected eye was not significantly associated with IV-MP (visual acuity difference 0.02 vs -0.28 LogMar), even in the case of early management, i.e., within the first 48hours after the onset of PVI (n=61; visual acuity difference -0.11 vs 0.25 LogMar). Complications attributable to corticosteroid therapy in the first month were significantly more frequent in the IV-MP group (31.8 vs 10.7%; P<0.05).

DISCUSSION

Our data do not support the routine use of pulse IV-MP for GCA complicated by unilateral PVI to avoid bilateral ophthalmologic damage. It might be safer to not give pulse IV-MP to selected patients with high risks of glucocorticoids pulse side effects. A prospective randomised multicentre study comparing pulse IV-MP and prednisone at 1mg/kg per day is desirable.

Prevalence and risk factors of ischemic monocular vision loss and concurrent brain ischemia

INTRODUCTION

We performed a retrospective cohort study to identify predictors of concurrent asymptomatic brain ischemia in patients with ischemic monocular vision loss.

PATIENTS AND METHODS

An inpatient database research of admissions to the Helios University Hospital Wuppertal, Germany between 01/2016 and 12/2020 was conducted. Inclusion criteria were confirmed diagnosis of transient monocular vision loss (MVL), retinal artery occlusion (RAO), and magnetic resonance imaging (MRI) of the brain within 10 days of MVL. Silent brain ischemia (SBI) was defined as diffusion restrictions with corresponding reduced apparent diffusion coefficient in MRI and an absence of neurological deficits besides those complying with MVL in clinical examination. The prevalence and cardiovascular predictors of SBI were analyzed with logistic regression and an artificial neural network.

RESULTS

One hundred fourteen out of 475 patients treated with monocular vision loss were included in this study. The mean age was 67.7 ± 13.6 years. 48.2% were male and 47.4% had RAO. MRI scan of the brain was performed after 3.9 ± 2.3 days and detected SBI in 17%. Age ⩾67 years, cardiac etiology of MVL, and cerebral ischemia in medical history were revealed as predictors of SBI in MRI.

CONCLUSIONS

Patients older than 66 years, with a suspected cardiac embolism as the cause of RAO and previous cerebral ischemia, are more likely to present SBI in cerebral MRI. Therefore, MR imaging, particularly in these patients, can be useful.

Long-term Prognosis of Vision Loss Caused by Facial Hyaluronic Acid Injections and the Potential Approaches to Address This Catastrophic Event

BACKGROUND

Vision loss is a serious complication of hyaluronic acid (HA) filler injections, and long-term observations regarding the prognosis, particularly with angiography, are rare.

OBJECTIVES

This study aimed to investigate the long-term prognosis and living status of patients with visual defects due to HA filler injections.

METHODS

Nine patients with vision loss caused by HA filler injections and receiving different treatments were included and followed up for 2 to 6 years after their accident. Follow-ups, including outpatient ophthalmologic examinations, were performed.

RESULTS

In the follow-up observation, all patients had reintegrated into society and work. The prognosis was similar for all hyaluronidase treatments, including retrobulbar injections and superselective ophthalmic artery thrombolysis. The facial appearance was not remarkably affected, and only 3 patients reported slight scarring. Ptosis disappeared in all the patients, and slight strabismus was found in 5 patients. However, vision improvement was very limited, even in the patients whose occluded retinal central artery received reperfusion.

CONCLUSIONS

This long-term follow-up showed that the patients with vision loss caused by HA filler injections could reintegrate into society after treatment. Although the embolization of the retinal central artery led to reperfusion, vision was not restored, which further demonstrated the difficulty of recovering vision with the current treatment and the importance of prophylaxis. Autohydrolysis of HA by incorporating hyaluronidase-containing stimuli-responsive nanoparticles and a dual-pipe syringe are potential future approaches to address this catastrophic event.

Thrombolysis in central retinal artery occlusion: a retrospective observational study

BACKGROUND

There is no evidence-based therapy for non-arteritic central retinal artery occlusion (NA-CRAO). Intravenous thrombolysis (IVT) with alteplase in a time window < 4.5 h may lead to a favorable outcome. Purpose of this study was to investigate the feasibility, efficacy and safety of IVT in patients classified as functionally blind.

METHODS

We conducted a retrospective observational study of NA-CRAO-patients. All patients underwent an ophthalmological and neurological examination including cerebral magnetic resonance imaging (MRI) for assessment of additional stroke lesions. Patients were treated either conservatively or with IVT within 4.5 h. Visual acuity (VA) was evaluated in logMAR and a categorical analysis was performed.

RESULTS

Thirty-seven patients were included in the study, 21 patients in the conservative treatment group (CTG) and 16 patients in the IVT group. The median logMAR visual acuity at admission and discharge was similar in both groups. The medium symptom to treatment time in the IVT group was 158.0 min. 3 patients (19%) of the IVT group showed a favorable outcome, all CTG patients remained at the level of functional blindness. No serious adverse events were observed after IVT. MRI showed additional acute stroke in over one-third of the patients (n = 14).

CONCLUSIONS

Early intravenous thrombolysis therapy according to the current stroke protocol n a time window up to 4.5 h after the onset of symptoms was feasible and might be a potential treatment option for NA-CRAO. Patients with NA-CRAO are at very high risk of ischemic stroke and MRI should be done in all patients for optimized treatment and secondary stroke prevention. A prospective randomized study is required.

The Possible Protective Effects of Ondansetron and Tropisetron on Optic Nerve Crush Injury in Rats

BACKGROUND

This study aimed to evaluate the potential neuroprotective effect of cyclosporine - a calcineurin inhibitor-, ondansetron, and tropisetron-5-hydroxytryptamine (serotonin) 3 receptor (5-HT3R) antagonists-, on optic nerve crush (ONC) injury in rats. Moreover, underlying signaling activities of their beneficial neuroprotective effects were studied.

METHODS

Adult male rats were treated with the intravitreal administration of cyclosporine (1.6 mM), ondansetron (100 nM), and tropisetron (100 nM) immediately after the induction of ONC. Subsequently, on 7th day after surgery, the rats' retinas were extracted, and the expression of apoptotic regulators (Bax and Bcl-2) and calcineurin were studied by western blot analysis.

RESULTS

The induction of ONC injury was associated to higher expression of Bax and calcineurin, while Bcl-2 expression was considerably decreased in these animals. Intravitreal treatment with cyclosporine (1.6 mM), ondansetron (100 nM), and tropisetron (100 nM) significantly attenuated the increased expression of Bax and calcineurin. Moreover, the treatment with these agents resulted in an elevated expression of Bcl-2 in the retina.

CONCLUSION

Our findings indicate that cyclosporine, ondansetron, and tropisetron protect against ONC injury in rats, possibly via the suppression of apoptosis and modulation of calcineurin activity directly and via 5-HT3 receptors. Moreover, immunoblotting showed that tropisetron was more effective as opposed to ondansetron. Further studies are needed to evaluate the precise mechanism behind cyclosporine, ondansetron, and tropisetron activities.

Redefining the Koizumi model of mouse cerebral ischemia: A comparative longitudinal study of cerebral and retinal ischemia in the Koizumi and Longa middle cerebral artery occlusion models

Cerebral and retinal ischemia share similar pathogenesis and epidemiology, each carrying both acute and prolonged risk of the other and often co-occurring. The most used preclinical stroke models, the Koizumi and Longa middle cerebral artery occlusion (MCAO) methods, have reported retinal damage with great variability, leaving the disruption of retinal blood supply via MCAO poorly investigated, even providing conflicting assumptions on the origin of the ophthalmic artery in rodents. The aim of our study was to use longitudinal in vivo magnetic resonance assessment of cerebral and retinal vascular perfusion after the ischemic injury to clarify whether and how the Koizumi and Longa methods induce retinal ischemia and how they differ in terms of cerebral and retinal lesion evolution. We provided anatomical evidence of the origin of the ophthalmic artery in mice from the pterygopalatine artery. Following the Koizumi surgery, retinal responses to ischemia overlapped with those in the brain, resulting in permanent damage. In contrast, the Longa method produced only extensive cerebral lesions, with greater tissue loss than in the Koizumi method. Additionally, our data suggests the Koizumi method should be redefined as a model of ischemia with chronic hypoperfusion rather than of ischemia and reperfusion.

Perioperative Care of the Patient with Eye Pathologies Undergoing Nonocular Surgery

The authors reviewed perioperative ocular complications and implications of ocular diseases during nonocular surgeries. Exposure keratopathy, the most common perioperative eye injury, is preventable. Ischemic optic neuropathy, the leading cause of perioperative blindness, has well-defined risk factors. The incidence of ischemic optic neuropathy after spine fusion, but not cardiac surgery, has been decreasing. Central retinal artery occlusion during spine fusion surgery can be prevented by protecting eyes from compression. Perioperative acute angle closure glaucoma is a vision-threatening emergency that can be successfully treated by rapid reduction of elevated intraocular pressure. Differential diagnoses of visual dysfunction in the perioperative period and treatments are detailed. Although glaucoma is increasingly prevalent and often questions arise concerning perioperative anesthetic management, evidence-based recommendations to guide safe anesthesia care in patients with glaucoma are currently lacking. Patients with low vision present challenges to the anesthesia provider that are becoming more common as the population ages.

Retinal and optic nerve magnetic resonance diffusion-weighted imaging in acute non-arteritic central retinal artery occlusion

OBJECTIVES

Diffusion weighted imaging hyperintensity (DWI-H) has been described in the retina and optic nerve during acute central retinal artery occlusion (CRAO). We aimed to determine whether DWI-H can be accurately identified on standard brain magnetic resonance imaging (MRI) in non-arteritic CRAO patients at two tertiary academic centers.

MATERIALS AND METHODS

Retrospective cross-sectional study that included all consecutive adult patients with confirmed acute non-arteritic CRAO and brain MRI performed within 14 days of CRAO. At each center, two neuroradiologists masked to patient clinical data reviewed each MRI for DWI-H in the retina and optic nerve, first independently then together. Statistical analysis for inter-rater reliability and correlation with clinical data was performed.

RESULTS

We included 204 patients [mean age 67.9±14.6 years; 47.5% females; median time from CRAO to MRI 1 day (IQR 1-4.3); 1.5 T in 127/204 (62.3%) and 3.0 T in 77/204 (37.7%)]. Inter-rater reliability varied between centers (κ = 0.27 vs. κ = 0.65) and was better for retinal DWI-H. Miss and error rates significantly differed between neuroradiologists at each center. After consensus review, DWI-H was identified in 87/204 (42.6%) patients [miss rate 117/204 (57.4%) and error rate 11/87 (12.6%)]. Significantly more patients without DWI-H had good visual acuity at follow-up (p = 0.038).

CONCLUSIONS

In this real-world case series, differences in agreement and interpretation accuracy among neuroradiologists limited the role of DWI-H in diagnosing acute CRAO on standard MRI. DWI-H was identified in 42.6% of patients and was more accurately detected in the retina than in the optic nerve. Further studies are needed with standardized novel MRI protocols.

Central Retinal Artery Occlusion: Current Practice, Awareness and Prehospital Delays in Switzerland

Background and Purpose

Central retinal artery occlusion (CRAO) often leads to permanent monocular blindness. Hence, early recognition and rapid re-perfusion is of paramount importance. This study aims to describe prehospital pathways in CRAO compared to stroke and study the knowledge about CRAO.

Methods

(1) Description of baseline characteristics, prehospital pathways/delays, and acute treatment (thrombolysis/thrombectomy vs. standard of care) of patients with CRAO and ischemic stroke registered in the Swiss Stroke Registry. (2) Online survey about CRAO knowledge amongst population, general practitioners (GPs) and ophthalmologists in Eastern Switzerland.

Results

Three hundred and ninety seven CRAO and 32,816 ischemic stroke cases were registered from 2014 until 2019 in 20 Stroke Centers/Units in Switzerland. In CRAO, 25.6% arrived at the hospital within 4 h of symptom onset and had a lower rate of emergency referrals. Hence, the symptom-to-door time was significantly longer in CRAO compared to stroke (852 min. vs. 300 min). The thrombolysis/thrombectomy rate was 13.2% in CRAO and 30.9% in stroke. 28.6% of the surveyed population recognized CRAO-symptoms, 55.4% of which would present directly to the emergency department in contrast to 90.0% with stroke symptoms. Almost 100% of the ophthalmologist and general practitioners recognized CRAO as a medical emergency and 1/3 of them considered IV thrombolysis a potentially beneficial therapy.

Conclusions

CRAO awareness of the general population and physician awareness about the treatment options as well as the non-standardized prehospital organization, seems to be the main reason for the prehospital delays and impedes treating CRAO patients. Educational efforts should be undertaken to improve awareness about CRAO.

INTRAVENOUS THROMBOLYTIC THERAPY FOR ACUTE NONARTERITIC CENTRAL RETINAL ARTERY OCCLUSION. A REVIEW

Central retinal artery occlusion (CRAO) is a form of acute ischemic stroke. It is a critical condition that often leads to severe visual loss or blindness and can be a harbinger of further cerebrovascular events. Due to the lack of scientific data, there are no effective evidence-based forms of therapy for this condition. None of the conservative therapies have proven effective. The results of some previously published studies suggest a benefit of intravenous thrombolytic therapy in the same regimen as in the treatment of ischemic stroke. This work aims to present an overview of published clinical studies focused on the use of intravenous thrombolysis for CRAO, evaluate its efficacy and safety, and propose an optimal diagnostic and therapeutic algorithm for acute management of CRAO. Summary statistics of patient data from relevant studies indicate that a significant visual acuity improvement was achieved by a total of 45 % of patients receiving alteplase within 4.5 hours of symptoms onset. The occurrence of adverse events in this time window was not significant. Intravenous thrombolytic therapy in CRAO thus appears to be effective and safe. However, we still lack data from adequate prospective randomized controlled trials to confirm this conclusion. To date, two randomized trials are being conducted. The intravenous thrombolysis administration, patient monitoring, etiologic workup, and setting of effective secondary prevention should be ensured at the centre of highly specialized cerebrovascular care. Urgent transport of the CRAO patient to the nearest centre is essential.

Efficacy of Intra-Arterial Thrombolysis for Acute Central Retinal Artery Occlusion: A Meta-Analysis

INTRODUCTION

The best management strategy still remains strong controversy for acute nonarteritic central retinal artery occlusion (CRAO). We thus performed a meta-analysis to determine the efficacy of intra-arterial thrombolysis (IAT) for visual improvement according to different times from symptom onset.

METHODS

We searched EMBASE, PubMed, and Web of Science for relevant studies assessing efficiency of IAT in patients with CRAO compared with standard therapy. Fixed-effects and random-effects models were performed.

RESULTS

Five eligible studies including 459 patients with acute CRAO were pooled in the meta-analysis. In all, 219 (47.7%) received IAT, and the mean time from symptom onset to IAT was 13 h. The pooled analysis demonstrates odds ratio (OR) for the procedure of IAT and any visual improvement to be 1.520 (95% confidence intervals [CIs] 1.258-1.837; p < 0.001). Subgroup analyses further indicated that the CRAO patients who received IAT achieved any visual improvement more easily within 6 h from symptom onset (OR = 1.703, 95% CI 1.219-2.381; p = 0.002), but not those beyond 6 h (OR = 1.260, 95% CI 0.973-1.632; p = 0.080).

CONCLUSION

Our meta-analysis of available published data supports IAT to be an alternative treatment option for CRAO patients within 6 h from symptom onset.

[Orbital Trauma]

Orbital trauma is a common medical emergency with potentially sight-threatening complications. Due to the confined orbital conditions, any direct injury or space-consuming lesion may cause serious tissue damage. Possible complications are orbital fractures, foreign body injuries, development of orbital compartment syndrome and traumatic optic neuropathy. Clinical signs include periorbital hematoma or emphysema, subconjunctival hemorrhage, proptosis, decreased ocular mobility, decreased vision, increased intraocular pressure and relative afferent pupillary defect. Ophthalmic status and low-dose CT-imaging provide key information regarding the therapeutic decision. Treatment options include surgical exploration, reconstruction or decompression or a conservative approach with anti-inflammatory or anti-glaucomatous medication. Rapid interdisciplinary diagnostics and therapy is critical for early detection and prevention of irreversible functional loss respectively. Considering the frequent association with life-threatening comorbidities diagnosis may be complicated.

Trauma der Orbita

Die Behandlung orbitaler Verletzungen gehört zum Alltag der medizinischen Akutversorgung. Bei 10 – 25% aller Gesichtsverletzungen ist die Orbita beteiligt. Dieser Beitrag gibt einen Überblick über die möglichen Pathologien nach Orbitatrauma sowie das primärdiagnostische Vorgehen und die therapeutischen Optionen.

The Effects of Hyperbaric Oxygen Therapy in Patients with Central Retinal Artery Occlusion - A Retrospective Study, Systematic Review and Meta-analysis

Purpose

Central retinal artery occlusion (CRAO) is a vision-threatening condition with a potentially poor visual prognosis. Many different treatment modalities are suggested but controversy remains regarding effectiveness of these treatments. The purpose of this study is to perform a systematic review and meta-analysis in addition to analyzing retrospective data at our own tertiary care center regarding effectiveness of hyperbaric oxygen therapy (HBOT) in treatment of CRAO.

Methods

The PubMed, Scopus, and the Cochrane Library are searched from the date of database inception to September 2021 to conduct a review based on the PRISMA (preferred reporting items for systematic review and meta-analysis), evaluating the role of HBOT in visual recovery of CRAO patients. In addition, a retrospective chart review of patients clinically diagnosed with CRAO at our university-based hospital (University of Texas Health, San Antonio, TX, USA) from year 2011 to 2021 was conducted.

Results

After a review of 376 articles, three articles met the inclusion criteria for meta-analysis, where a total of 207 patients received HBOT versus 89 patients that did not receive any form of oxygen therapy. Analysis of these results demonstrate that HBOT in CRAO patients does not enhance the final visual outcome (p = 0.83). Similar conclusion was also drawn from retrospective analysis of 48 patients (15 HBOT versus 33 controls) at our tertiary care center, where no visual benefit was observed in the HBOT group.

Conclusions

HBOT does not appear to improve final visual outcome and concerns remain regarding adverse reactions such as barotrauma and generalized seizures. Large, randomized studies are required for further understanding of the role of HBOT in treatment of CRAO.

Epidemiology of Ocular Manifestations in Autoimmune Disease

The global prevalence of autoimmune diseases is increasing. As a result, ocular complications, ranging from minor symptoms to sight-threatening scenarios, associated with autoimmune diseases have also risen. These ocular manifestations can result from the disease itself or treatments used to combat the primary autoimmune disease. This review provides detailed insights into the epidemiological factors affecting the increasing prevalence of ocular complications associated with several autoimmune disorders.

Diterpene Ginkgolides Meglumine Injection inhibits apoptosis induced by optic nerve crush injury via modulating MAPKs signaling pathways in retinal ganglion cells

ETHNOPHARMACOLOGICAL RELEVANCE

Diterpene Ginkgolides Meglumine Injection (DGMI) is made of extracts from Ginkgo biloba L, including Ginkgolides A, B, and K and some other contents, and has been widely used as the treatment of cerebral ischemic stroke in clinic. It can be learned from the "Compendium of Materia Medica" that Ginkgo possesses the effect of "dispersing toxin". The ancient Chinese phrase "dispersing toxin" is now explained as elimination of inflammation and oxidative state in human body. And it led to the original ideas for today's anti-oxidation studies of Ginkgo in apoptosis induced by optic nerve crush injury.

AIM OF THE STUDY

To investigate the underlying molecular mechanism of the DGMI in retinal ganglion cells (RGCs) apoptosis.

MATERIALS AND METHODS

TUNEL staining was used to observe the anti-apoptotic effects of DGMI on the adult rat optic nerve injury (ONC) model, and flow cytometry and hoechst 33,342 staining were used to observe the anti-apoptotic effects of DGMI on the oxygen glucose deprivation (OGD) induced RGC-5 cells injury model. The regulation of apoptosis and MAPKs pathways were investigated with Immunohistochemistry and Western blotting.

RESULTS

This study demonstrated that DGMI is able to decrease the conduction time of F-VEP and ameliorate histological features induced by optic nerve crush injury in rats. Immunohistochemistry and TUNEL staining results indicated that DGMI can also inhibit cell apoptosis via modulating MAPKs signaling pathways. In addition, treatment with DGMI markedly improved the morphological structures and decreased the apoptotic index in RGC-5 cells. Mechanistically, DGMI could significantly inhibit cell apoptosis by inhibiting p38, JNK and Erk1/2 activation.

CONCLUSION

The study shows that DGMI and ginkgolides inhibit RGCs apoptosis by impeding the activation of MAPKs signaling pathways in vivo and in vitro. Therefore, the present study provided scientific evidence for the underlying mechanism of DGMI and ginkgolides on optic nerve crush injury.

Thrombolysis for Central Retinal Artery Occlusion in 2020: Time Is Vision!

BACKGROUND

Acute nonarteritic central retinal artery occlusion (CRAO) is an eye stroke with poor visual prognosis and no proven effective therapies. Given advances in acute stroke care, thrombolysis in CRAO merits critical re-examination. We review the evidence for intravenous (IV) and intra-arterial (IA) tissue plasminogen activator (tPA) in CRAO management.

EVIDENCE ACQUISITION

MEDLINE, Scopus, and Cochrane online databases were systematically searched from 1960 to present, for reports of acute IV or IA therapy with alteplase or tenecteplase in nonarteritic CRAO patients. English language case reports, case series, interventional studies, or randomized controlled trials were included. The study type, age and number of subjects, the regimen administered, the time since symptoms' onset, visual outcome, and safety reports were noted.

RESULTS

Use of IV thrombolysis with alteplase was reported in 7 articles encompassing 111 patients, with 54% of them receiving IV tPA within 4.5 hours of symptom onset, and none developing symptomatic intracranial or ocular hemorrhage. Six studies described IA alteplase administration, with only 18 of a total of 134 patients (13.4%) treated within the first 6 hours after visual loss. The reported adverse events were minimal. Visual outcomes post-IV and IA thrombolysis were heterogeneously reported; however, most studies demonstrated benefit of the respective reperfusion therapies when administered very early. We found no reports of tenecteplase administration in CRAO.

CONCLUSIONS

In 2020, nonarteritic CRAO patients should theoretically receive the same thrombolytic therapies, in the same time window, as patients with acute cerebral ischemia. Eye stroke and teleeye stroke code encounters must include an expert ophthalmologic evaluation to confirm the correct diagnosis and to evaluate for ocular signs that may help guide IV tPA administration or IA management. Future research should focus on developing feasible retinal penumbra imaging studies that, similar to cerebral tissue viability or perfusion imaging, can be incorporated into the thrombolysis decision-making algorithm.

Retinal emboli after cervicopetrous junction internal carotid artery pseudoaneurysm stenting

Purpose

To describe acute and chronic retinal ischemic changes following an internal carotid artery pseudoaneurysm stenting procedure, and to review current evidence for risk factors and management of post-procedural retinal ischemic events.

Observation

A 50-year-old man presented with a 3-month history of pulsatile tinnitus, headache, and intermittent blurry vision. A CT angiogram of head and neck showed bilateral cervicopetrous internal carotid artery (ICA) pseudoaneurysms. The patient underwent successful repair with angioplasty and stenting of the flow-limiting high-grade (>95%) stenosis of his left high cervical ICA. On post-operative day 1, the patient reported monocular vision loss with a large central scotoma. He was found to have a central macular area of retinal whitening and multiple areas of perivascular retinal whitening on exam, concerning for retinal artery occlusions secondary to peri-procedural emboli. Dual antiplatelet therapy was started and a stroke evaluation was performed. Two months later, his visual acuity in the affected eye was counting fingers and his left eye fundus examination was notable for multiple areas of scattered hemorrhages, microaneurysms, and retinal exudates in the distribution of prior retinal ischemia. OCT imaging revealed atrophic changes in the left macula. Subsequently, the patient completed stage-2 repair of the left ICA pseudoaneurysm followed by uncomplicated repair of the right ICA. Four months later, his left eye visual acuity and retinal findings remained stable.

Conclusions and Importance

Post-procedure retinal emboli and ischemia are important, vision threatening possible ocular complications for patients undergoing carotid vascular and endovascular procedures.

Evaluation of the change in retinal thickness after femtosecond laser-assisted laser in situ keratomileusis and photorefractive keratectomy

PURPOSE OF THE STUDY

To investigate the change in individual retinal layer thickness by spectral-domain optical coherence tomography (SD-OCT) in eyes underwent femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and photorefractive keratectomy (PRK).

METHODS

In patients who underwent PRK and FS-LASIK, changes in the thickness of all retinal layers in the foveal, parafoveal, and perifoveal regions were evaluated by SD-OCT automated segmentation analysis at pre-operatively and different time points post-operatively.

RESULTS

Seventy-one eyes of 71 patients (38 patients in PRK, 33 patients in LASIK) were included. In the pre-operative period, mean spherical equivalent (SE), mean keratometry, axial length, and segmentation values of the retinal layers were similar (P> .05). In the PRK group, the pre-operative measurements of individual retinal layers did not show a statistically significant difference compared to the post-operative measurements on the 1st day, 1st week, and 1st month. In the FS-LASIK group, the mean inner nuclear layer (INL) thickness one day after the surgery was significantly higher than that before surgery in the foveal (21.22 ± 4.66 µm vs 19.03 ± 4.50 µm, P= .013) and parafoveal regions (41.98 ± 3.70 µm vs 40.56 ± 3.49 µm, P= .044).

CONCLUSIONS

The findings of our study suggest that the increase of INL thickness may be due to temporary structural and circulatory changes of the retina that may occur in the suction phase in the FS-LASIK procedure.

Structural and Functional Imaging of the Retina in Central Retinal Artery Occlusion - Current Approaches and Future Directions

Central retinal artery occlusion (CRAO) is a form of acute ischemic stroke which affects the retina. Intravenous thrombolysis is emerging as a compelling therapeutic approach. However, it is not known which patients may benefit from this therapy because there are no imaging modalities that adequately distinguish viable retina from irreversibly infarcted retina. The inner retina receives arterial supply from the central retinal artery and there is robust collateralization between this circulation and the outer retinal circulation, provided by the posterior ciliary circulation. Fundus photography can show canonical changes associated with CRAO including a cherry-red spot, arteriolar boxcarring and retinal pallor. Fluorescein angiography provides 2-dimensional imaging of the retinal circulation and can distinguish a complete from a partial CRAO as well as central versus peripheral retinal non-perfusion. Transorbital ultrasonography may assay flow through the central retinal artery and is useful in the exclusion of other orbital pathology that can mimic CRAO. Optical coherence tomography provides structural information on the different layers of the retina and exploratory work has described its utility in determining the time since onset of ischemia. Two experimental techniques are discussed. 1) Retinal functional imaging permits generation of capillary perfusion maps and can assay retinal oxygenation and blood flow velocity. 2) Photoacoustic imaging combines the principles of optical excitation and ultrasonic detection and - in animal studies - has been used to determine the retinal oxygen metabolic rate. Future techniques to determine retinal viability in clinical practice will require rapid, easily used, and reproducible methods that can be deployed in the emergency setting.

Activation of Cytosolic Calpain, Not Caspase, Is Underlying Mechanism for Hypoxic RGC Damage in Human Retinal Explants

Purpose

Activation of proteolytic enzymes, calpains and caspases, have been observed in many models of retinal disease. We previously demonstrated calpain activation in monkey retinal explants cultured under hypoxia. However, cellular responses are often species-specific. The purpose of the present study was to determine whether calpains or caspase-3 was involved in retinal ganglion cell (RGC) damage caused by hypoxia/reoxygenation in human retinal explants. The explant model was improved by use of an oxygen-controlled chamber.

Methods

Human and monkey retinal explants were cultured under hypoxic conditions in an oxygen-controlled chamber and then reoxygenated. Calpain inhibitor SNJ-1945 was maintained throughout the culture period. Immunohistochemistry and immunoblotting were performed for calpains 1 and 2, calpastatin, α-spectrin, calpain-specific α-spectrin breakdown product at 150 kDa (SBDP150), caspase-3, and apoptosis-inducing factor (AIF). Propidium iodide (PI) staining measured membrane disruption, and TUNEL staining detected DNA fragmentation.

Results

Activation of calpains in nerve fibers and increases of PI-positive RGCs were observed in retinal explants incubated for 16-hour hypoxia/8-hour reoxygenation. Except for autolysis of calpain 2, SNJ-1945 ameliorated these changes. In longer incubations under 24-hour hypoxia/16-hour reoxygenation, TUNEL-positive cells appeared, although activated caspase-3 and truncated AIF were not observed. DNA fragmentation was inhibited by SNJ-1945.

Conclusions

An improved human retinal explant model showed that calpains, not caspase-3, were involved in cell damage induced by hypoxia/reoxygenation. This finding could be relevant for patient treatment with a calpain inhibitor if calpain activation is documented in human retinal ischemic diseases.

Management of Central Retinal Artery Occlusion: A Scientific Statement From the American Heart Association

PURPOSE

Central retinal artery occlusion (CRAO) is a form of acute ischemic stroke that causes severe visual loss and is a harbinger of further cerebrovascular and cardiovascular events. There is a paucity of scientific information on the appropriate management of CRAO, with most strategies based on observational literature and expert opinion. In this scientific statement, we critically appraise the literature on CRAO and provide a framework within which to consider acute treatment and secondary prevention.

METHODS

We performed a literature review of randomized controlled clinical trials, prospective and retrospective cohort studies, case-control studies, case reports, clinical guidelines, review articles, basic science articles, and editorials concerning the management of CRAO. We assembled a panel comprising experts in the fields of vascular neurology, neuro-ophthalmology, vitreo-retinal surgery, immunology, endovascular neurosurgery, and cardiology, and document sections were divided among the writing group members. Each member received an assignment to perform a literature review, synthesize the data, and offer considerations for practice. Multiple drafts were circulated among the group until consensus was achieved.

RESULTS

Acute CRAO is a medical emergency. Systems of care should evolve to prioritize early recognition and triage of CRAO to emergency medical attention. There is considerable variability in management patterns among practitioners, institutions, and subspecialty groups. The current literature suggests that treatment with intravenous tissue plasminogen activator may be effective. Patients should undergo urgent screening and treatment of vascular risk factors. There is a need for high-quality, randomized clinical trials in this field.

Endovascular Hyaluronidase Application Through Superselective Angiography to Rescue Blindness Caused by Hyaluronic Acid Injection

BACKGROUND

Blindness is a rare but catastrophic complication of facial hyaluronic acid (HA) injection. Although various means to rescue visual impairment have been employed, no consensus regarding effective treatment has yet been reached. We organized a multidisciplinary team to address this emergency situation by means of endovascular hyaluronidase application.

OBJECTIVES

The aim of this study was to investigate the direct delivery of hyaluronidase to ophthalmic artery occlusion through endovascular cannulation to resolve HA-induced blindness.

METHODS

Four patients with visual impairments caused by HA filler embolization were subjected to sequential treatments. Through superselective angiography, a microcatheter was introduced along a guidewire from the femoral artery to the ophthalmic artery to directly deliver hyaluronidase to the HA embolism. The safety and efficiency of this treatment were systematically analyzed.

RESULTS

Selective cerebral angiography demonstrated that the endovascular application of hyaluronidase significantly alleviated occlusion in 3 patients. One patient showed slight visual improvement, whereas the other patients showed no improvement in their visual function during a follow-up period of more than 3 months. One patient suffered from cerebral infarction in the left middle cerebral artery during the intervention surgery. Moreover, 2 patients showed multiple lacunar cerebral infarctions after the operation, whereas none exhibited symptoms of hemiplegia during follow-up.

CONCLUSIONS

Although the endovascular application of hyaluronidase could partially recanalize the occluded branches of the ophthalmic artery, it had limited effects on restoring vision. Considering the risks of vascular intervention surgery, this approach should be considered with caution.

LEVEL OF EVIDENCE: 5

Conservative treatments for acute nonarteritic central retinal artery occlusion: Do they work?

Acute central retinal arterial occlusion has a very poor visual prognosis. Unfortunately, there is a dearth of evidence to support the use of any of the so-called "conservative" treatment options for CRAO, and the use of thrombolytics remains controversial. In this review, we address a variety of these "conservative" pharmacologic treatments (pentoxifylline, isosorbide dinitrate, and acetazolamide) and nonpharmacologic approaches (carbogen, hyperbaric oxygen, ocular massage, anterior chamber paracentesis, laser embolectomy, and hemodilution) that have been proposed as potential treatments of this condition. We conclude that the available evidence for all treatments is insufficient to conclude that any treatment will influence the natural history of this disorder. Management of CRAO patients should instead focus on reducing the risk of subsequent ischemic events, including cerebral stroke. Certain patients may be considered for acute treatment with thrombolytics, although further research must clarify the efficacy, safety, and optimal use of these therapies.

Optic nerve head anatomy in myopia and glaucoma, including parapapillary zones alpha, beta, gamma and delta: Histology and clinical features

The optic nerve head can morphologically be differentiated into the optic disc with the lamina cribrosa as its basis, and the parapapillary region with zones alpha (irregular pigmentation due to irregularities of the retinal pigment epithelium (RPE) and peripheral location), beta zone (complete RPE loss while Bruch's membrane (BM) is present), gamma zone (absence of BM), and delta zone (elongated and thinned peripapillary scleral flange) within gamma zone and located at the peripapillary ring. Alpha zone is present in almost all eyes. Beta zone is associated with glaucoma and may develop due to a IOP rise-dependent parapapillary up-piling of RPE. Gamma zone may develop due to a shift of the non-enlarged BM opening (BMO) in moderate myopia, while in highly myopic eyes, the BMO enlarges and a circular gamma zone and delta zone develop. The ophthalmoscopic shape and size of the optic disc is markedly influenced by a myopic shift of BMO, usually into the temporal direction, leading to a BM overhanging into the intrapapillary compartment at the nasal disc border, a secondary lack of BM in the temporal parapapillary region (leading to gamma zone in non-highly myopic eyes), and an ocular optic nerve canal running obliquely from centrally posteriorly to nasally anteriorly. In highly myopic eyes (cut-off for high myopia at approximately -8 diopters or an axial length of 26.5 mm), the optic disc area enlarges, the lamina cribrosa thus enlarges in area and decreases in thickness, and the BMO increases, leading to a circular gamma zone and delta zone in highly myopic eyes.

[Delays in the management of ocular complications of giant cell arteritis: A retrospective monocentric study of 33 patients]

INTRODUCTION

Ocular complications of giant cell arteritis (GCA) can lead to irreversible bilateral blindness and represent a therapeutic emergency. Recommendations for the management of GCA have recently been updated. The objective of the study was to evaluate delays in appropriate management of the ocular complications of GCA and its determinants.

METHOD

Retrospective, monocentric study, conducted over the period January 2013-November 2018. All consecutive patients with a final diagnosis of GCA and related visual impairment (permanent visual loss and/or alteration of visual field) were included.

RESULTS

Thirty-three patients were included (women: 21, men: 12; mean age at diagnosis: 79). Twenty-seven patients (82%) presented with symptoms suggestive of ACG prior to the visual complication, ranging from a few weeks to several months. Seventeen patients (52%) had a known biological inflammatory syndrome (median CRP at 64 mg/L) prior to hospital consultation. The median time from the onset of permanent ophthalmologic manifestations to appropriate corticosteroid management was 3 days (range: 0-134). Two of the 21 patients who consulted an out-of-hospital ophthalmologist received corticosteroid therapy before referral to hospital. Three patients (9%) were treated within 24 h of the onset of the disorders.

CONCLUSION

There is a significant delay in the appropriate management of ophthalmological complications of ACG and deviations from current recommendations. Numerous actions must therefore be taken to improve the visual prognosis of patients with ACG, both preventively (i.e. early diagnosis and treatment of ACG before the possible occurrence of visual complications), and curatively (rapid recognition and immediate treatment of ocular complications). These elements support the relevance of specific fast-track pathways for GCA.

Subclinical inner retinal layer thickness changes in the fellow eyes of patients with unilateral central retinal artery occlusion: a pilot study

PURPOSE

To investigate microstructural changes in the macular inner retinal layers over time in the fellow eyes of patients with unilateral central retinal artery occlusion (CRAO).

METHODS

Spectral-domain optical coherence tomography scans of 16 patients with CRAO were performed at initial examination (1st day), at 1st month, at 3rd month, at 6th month, and the central macular thickness (CMT) and inner retinal layer thicknesses in the fellow eyes of the patients were compared between each visit. The thicknesses of retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), and inner nuclear layer (INL) were calculated in 9 quadrants according to the definition by the Early Treatment Diabetic Retinopathy Study.

RESULTS

CMT decreased over a 6-month period, but the difference was insignificant among visits (p = 0.072). Also, there were no significant differences in the thicknesses of RNFL and GCL among visits (p > 0.05 for all quadrants). But there was thinning in the parafoveal superior and perifoveal superior quadrants of the IPL (p = 0.007, p = 0.01) and in the parafoveal temporal quadrant of the INL (p = 0.033) within 6 months of follow-up in the fellow eyes of the patients with CRAO.

CONCLUSION

This study demonstrated subclinical alterations of the macular inner retinal layers over time in the fellow eyes of CRAO patients.

Arterial Occlusions to the Eye: From Retinal Emboli to Ocular Ischemic Syndrome

: Abstract: A loss or lack of blood supply to the eye can result in acute loss of vision. The site of ischemia may be at the level of the retinal arterioles, the central retinal artery, or further back at the ophthalmic and internal carotid artery. Recognizing the symptoms and signs are important to help prevent permanent ischemic and irreversible blindness. The objective of this review article is to provide the general ophthalmologists with information on how to recognize the symptoms and to best manage these patients. The management is to investigate for the cause of the transient monocular visual loss and to apply secondary prevention to address atherosclerotic risk factors to prevent further ischemic events like a stroke.

Efficacy of vertical lid split versus lateral canthotomy and cantholysis in the management of orbital compartment syndrome

Purpose: To compare the efficacy of the vertical lid split (VLS) to the standard lateral canthotomy and cantholysis (LC/C) for orbital compartment syndrome (OCS) in the cadaveric model.Methods: Simulated OCS was achieved in seven fresh frozen cadaveric orbits. Orbital pressure (OP) was monitored in one control orbit and six interventional orbits. Initial OP was recorded before three right orbits underwent lateral canthotomy with superior and inferior cantholysis, and three left orbits underwent vertical lid split of the upper and lower eyelids. In all 7 orbits, OP was recorded for a total of 16 min. The main outcome measure was the amount of OP reduction at timed intervals.Results: Beginning OP in the control orbit was 109 mmHg, and average initial OP of the LC/C and VLS orbits were 90 and 103 mmHg, respectively. The control orbit maintained high OP without intervention. One minute after LC/C, OP decreased an average of 58.7 mmHg (65.2%; range 48-65 mmHg). One minute following VLS, OP decreased an average of 63 mmHg (61.0%; range 39-102 mmHg). At 16 min, OP reduction in the LC/C orbits averaged 65.3 mmHg (72.6%; range 56-71 mmHg), and OP reduction in the VLS orbits averaged 78 mmHg (75.5%; range 54-121 mmHg). Both interventions produced a comparable reduction in OP.Conclusions: Vertical lid split was found to be as effective as LC/C in reducing OP. The technical simplicity of the VLS lends itself well to utilization by physicians who are unfamiliar with eyelid surgery.

Novel Application of Point-of-Care Ocular Ultrasound in a Left Central Retinal Artery Occlusion

Central retinal artery occlusion represents a vision-threatening entity in those presenting with monocular painless vision loss, especially in the elderly and those with cardiovascular comorbidities. While confirmation of this diagnosis requires consultation with an ophthalmologist, prompt recognition is the crucial action of the emergency physician to help reverse retinal ischemia and save vision. Here we describe the case of a central retinal artery occlusion identified on point-of-care ocular ultrasound and confirmed by fluorescein angiography.

Intra-Arterial Thrombolysis for Central Retinal Artery Occlusion

Introduction

Central retinal artery occlusion is an ophthalmic emergency which typically causes acute, painless visual loss. Several conservative treatment options are practiced with little benefit. Thrombolysis as a therapeutic option has gathered interest as well as controversy. This paper aims at reviewing the relevant literature to assess the efficacy and safety of intra-arterial thrombolysis for acute central retinal artery occlusion.

Methods

A review of the literature was conducted. Keywords included “intra-arterial thrombolysis” or “intra-arterial fibrinolysis” in combination with “central retinal artery occlusion” or “CRAO”. A Cochrane Database search was performed for randomised control trials, systematic reviews and meta-analyses using the same keywords.

Results

Twenty-eight studies were identified which included case reports, case series, case-control studies and 1 randomised control trial: the European Assessment Group for Lysis in the Eye Study. Improvement in vision was measured using different methods and at different time points. The findings of these studies generally favour an effect towards intra-arterial thrombolysis however there are many limitations. Additionally, the European Assessment Group for Lysis in the Eye Study showed lack of effect in intra-arterial thrombolysis vs conservative measures.

Conclusion

Current evidence is not sufficient to recommend intra-arterial thrombolysis due to the variability of visual improvement within retrospective studies, heterogeneity in treatment regimens between studies and adverse effects. Intra-arterial thrombolysis may have a role in patients presenting early, particularly if they have monocular vision, after discussion of the risks and benefits. Further high-quality trials assessing the clinical efficacy of intra-arterial thrombolysis may shed more light on this topic.

Effect of vitrectomy with intrasurgical regulation of intraocular pressure in a rabbit model of central retinal artery occlusion

Central retinal artery occlusion (CRAO) is an ophthalmic emergency that causes severe and permanent visual impairment. The effects of conventional treatments on recanalizing retinal arteries and improving visual outcome are equivocal. This study was designed to determine the possible benefits of pars plana vitrectomy (PPV) with intrasurgical regulation of intraocular pressure using intraocular vascular counterpulsation (IVT). CRAO was induced by 532-nm argon green laser activation of auricular intravenous injected rose bengal, a photosensitive dye, in the central retinal arteries (CRA) of eighty-four New Zealand white albino rabbits. CRAO rabbits were randomly assigned to photocoagulation, vitrectomy and counterpulsation groups. Depending on the time intervals between surgery and CRAO induction, vitrectomy and counterpulsation groups were further divided into 2 h (2h), 6 h (6h) and 24 h (24h) subgroups. The proportion of eyes with complete recanalization was significantly higher in the 2h counterpulsation subgroup after three days (P = 0.032) and in all counterpulsation subgroups after one week (P = 0.020). After one month, the 2h and 6h counterpulsation subgroups showed greater oscillatory potential (OPs) responses (F = 3.519, P = 0.049). The 2h counterpulsation subgroup also exhibited greater b-wave amplitude in photopic 3.0 Flicker(F = 4.530, P = 0.044). Histologic evaluation revealed less destruction in the inner retina for the 2h and 6h counterpulsation subgroups. Expression of HSP70 was higher in the 2h and 6h counterpulsation subgroups (F = 48.915,P < 0.001). Levels of HSP90 were lower in all counterpulsation subgroups (F = 30.065,P < 0.001). Levels of TNF-α were lower in the 2h counterpulsation subgroup (F = 14.762,P < 0.001). These results indicate that PPV with IVT was effective to recanalize retinal arteries after CRAO. Early intervention provided better morphologic and functional prognosis for inner retina. The protective effect was related with higher retinal levels of HSP70 and lower levels of HSP90 and TNF-α.

Visual outcomes after traumatic retrobulbar hemorrhage are not related to time or intraocular pressure

BACKGROUND

The paucity of literature regarding the role of time and intraocular pressure (IOP) when treating ocular compartment syndrome (OCS) has resulted in limited guidance for emergency physicians (EP).

OBJECTIVES

Our goals were to investigate the ideal time frame for lateral canthotomy, to understand the relationship between IOP and visual outcome, and to determine the impact of EP performance on visual acuity (VA).

METHODS

The study population included patients presenting over an 18-year period with traumatic retrobulbar hemorrhage (RBH) treated with lateral canthotomy. Efficacy was evaluated using visual outcome and IOP. Patients were grouped by time from injury and arrival to canthotomy. Procedures completed in the emergency department (ED) and by EPs were evaluated regarding visual outcome.

RESULTS

Sixty cases of RBH treated with lateral canthotomy were identified. Over two-thirds (43/60, 71.7%) were discharged with baseline vision. Lateral canthotomy lowered IOP from a median of 50.0 mmHg (IQR: 40.5, 61) preprocedure to 23.0 mmHg (IQR: 18, 27) post-procedure (p-value = 0.000001). No correlation was found between time, IOP, location, specialty of clinician, and visual outcome.

CONCLUSION

Lateral canthotomy is an effective at lowering IOP. Our data suggest that using time and IOP to predict procedural outcome is flawed. If OCS is suspected, lateral canthotomy should be considered and can be effectively performed by EPs. Neither the time of injury to ED presentation nor degree of IOP elevation should be factored into the decision of when to perform the procedure.

An Anatomical Feasibility Study for Revascularization of the Ophthalmic Artery. Part II: Intraorbital Segment

INTRODUCTION

Distal ophthalmic artery (OpA) aneurysms are a rare subset of vascular lesions with lack of optimal treatment. The management of these aneurysms may require complete occlusion of the parent vessel, carrying a risk of permanent visual impairment due to individual variations of extracranial collateral flow to the intraorbital ophthalmic artery (iOpA).

OBJECTIVE

To test the feasibility of a superficial temporal artery (STA) to iOpA bypass to prevent acute ischemic retinal injury. Two different transorbital corridors (superomedial and posterolateral approaches) for this bypass were evaluated.

METHODS

Each approach was carried out in 10 specimens each (n = 20). The corridors were compared to achieve the optimal exposure of the iOpA until the central retinal artery origin was visualized. An end-to-end anastomosis was performed from STA-to-iOpA. The arterial caliber and length at the anastomotic sites, required donor artery length, and intraorbital surgical area were measured.

RESULTS

STA-iOpA bypasses were performed in all specimens. For the posterolateral transorbital approach, the mean caliber of STA was 1.8 ± 0.2 mm, and that of iOpA was 1.7 ± 0.5 mm. The required STA graft length was 78.3 ± 1 mm with lateral iOpA transposition of 8.2 ± 1.1 mm. For the superomedial approach, the average STA length required for an intraorbital bypass was 130.8 ± 14.0 mm. The mean calibers of iOpA and STA were 1.5 ± 0.1 mm and 1.5 ± 0.1 mm, respectively.

CONCLUSIONS

This study demonstrates the feasibility of a novel revascularization technique of the iOpA using 2 different transorbital approaches. These techniques can be used in the management of intraorbital lesions such as OpA aneurysms, tumoral infiltrations, or intraoperative injuries.

Animal Models Used to Simulate Retinal Artery Occlusion: A Comprehensive Review

Purpose

To present an overview of animal models of retinal artery occlusion (RAO).

Methods

Through a systematic literature search in PubMed and Embase, papers describing methods of inducing RAO in animal models were included. The identified methodologic approaches were presented in a narrative synthesis and compared with RAO in humans.

Results

In total, 83 papers reporting on 88 experiments were included. Six different species were used with rodents and monkeys being the most common, and a minority were performed using cats, dogs, rabbits, or pigs. The anatomy of pigs and monkeys resemble that of humans most closely. The two most frequently used methods were laser-induced occlusion or ligation of the arteries. Other methods included raised intraocular pressure, arterial clamping, administration of vasoconstricting agents, the use of an occluder, embolization, and endovascular approaches to induce occlusion. In general, occlusions lasted for only 30 to 90 minutes, often followed by reperfusion.

Conclusions

Although a broad range of methods have previously been used, they all have limitations. Preferably, the methods should imitate the human disease as closely as possible and avoid damaging other structures. Therefore, monkeys followed by pigs are to be preferred and ligation or clamping may be a suitable model in larger animals as there is a potential to isolate and occlude the retinal artery only. Being less invasive, laser-induced occlusion is another suitable approach.

Translational Relevance

This review aims at assisting researchers in deciding on the most ideal experimental setting, and thereby increase the translational value to human disease.