New concepts on acute ocular ischemia

Non-arteritic anterior ischaemic optic neuropathy (NA-AION) and COVID-19 vaccination

A woman in her 50s presented with diminution of vision in her left eye (OS) 4 days after COVISHIELD^TM vaccination. She had been diagnosed with non-arteritic anterior ischaemic optic neuropathy (NA-AION) of right eye (OD) 8 months earlier. The present episode revealed a best-corrected visual acuity (BCVA) of 20/50 in OD and 20/20 in OS with grade 1 relative afferent pupillary defect. Fundus evaluation showed pale disc in OD and temporal disc oedema in OS. Humphrey’s visual field analysis showed incomplete inferior altitudinal defect in OD and a centro-caecal scotoma in OS. Systemic investigations were normal. OS was diagnosed with NA-AION. She was started on oral aspirin 75 mg. At 1-month follow-up, disc oedema of OS had resolved with BCVA maintaining at 20/20. The patient was lost to follow-up later. The relationship between the vaccine and the ocular event is temporal with no causal association.

Optical coherence tomography angiography characteristics and correlated factors with visual acuity in retinal arterial occlusion

PURPOSE

To reveal the characteristics of vascular changes in retinal arterial occlusion (RAO) using optical coherence tomography angiography (OCTA) and determine the correlated factors with best-corrected visual acuity (BCVA).

METHODS

This retrospective study recruited 54 RAO patients and 27 healthy individuals. Ophthalmic examinations including BCVA and OCTA were performed in all the patients and individuals. The OCTA outcomes were analyzed using SPSS software, and the characteristics of vascular changes and BCVA-related factors were summarized.

RESULTS

The vessel density in all areas except fovea of both superficial capillary plexus (SCP) and deep capillary plexus (DCP) was significantly reduced in RAO eyes compared with the fellow eyes and normal control eyes (P < 0.05). The vessel density of DCP in all areas except fovea was significantly reduced in the fellow eyes compared with that in the normal control eyes as well (P < 0.05). The retinal thickness in fovea was significantly increased in RAO eyes compared with that in the fellow eyes and normal control eyes (P < 0.05), without any differences in other areas between the RAO eyes and the other two groups (P > 0.05). The retinal thickness in whole area and retinal thickness in fovea were correlated with BCVA, respectively (whole area: r = 0.295, P = 0.030; fovea: r = 0.322, P = 0.018).

CONCLUSIONS

OCTA is a fast, noninvasive, and effective examination means for RAO that can display the vascular density and retinal thickness quantitatively and distinctly. RAO patients had reduced vascular density in both eyes and increased foveal retinal thickness in RAO eyes, showing a correlation with BCVA.

Usefulness of orbital colour Doppler ultrasound in vascular-related monocular vision loss

Acute, painless, monocular vision loss (APMVL) usually has a vascular aetiology. We conducted a prospective observational study from 2011 to 2018 to analyse the added value of colour Doppler imaging to assess orbital vessel blood flow in the diagnosis of APMVL. The study included 67 patients (39 [58.2%] men; mean age, 65.9 years [SD 13.7]) with APMVL evaluated at the Neurosonology Laboratory within the first 5 days of symptom onset, who were classified as having either transient or persistent monocular blindness. The blood flow in the ophthalmic and central retinal arteries was assessed using colour Doppler ultrasound with a linear 7.5-MHz transducer. Thirty-three (49.3%) patients presented transient monocular blindness, with reduced blood flow in either the ophthalmic or central retinal artery. The group with persistent vision loss included 24 cases of central retinal artery occlusion (CRAO) and 10 cases of ischaemic optic neuropathy (35.8% and 14.9%, respectively, of the total sample). These patients were older and had a higher prevalence of hypertension and mild carotid atherosclerosis. Orbital colour Doppler ultrasound (OCDUS) clarified the mechanism/cause of the ischaemia in 11 (16.4%) patients and showed abnormal flow in 46 (68.7%) patients, confirming the vascular origin in 19 (57.6%) of the transient monocular blindness cases. Lower peak systolic velocity was observed in patients with CRAO (p < 0.001), and a velocity < 10 cm/s in the central retinal artery was independently associated with the diagnosis of CRAO. OCDUS can be helpful in confirming the vascular cause and identifying the aetiology of APMVL.

Transient Monocular Visual Loss: When Is It an Emergency?

BACKGROUND

Patients who experienced transient monocular vision loss (TMVL) commonly present to the emergency department for evaluation. Although multiple etiologies can cause TMVL, it is most important to identify patients with retinal ischemia and those with vasculitis (giant cell arteritis) as the cause of TMVL. Patients with transient retinal ischemia have the same risk of cardiovascular events and death as patients who experienced transient brain ischemia. Patients with giant cell arteritis are at imminent risk of visual loss.

CASE REPORT

A 65-year-old man noticed three separate episodes of sudden onset of blurry vision in one eye. Ophthalmologic examination was normal but, as his symptoms were compatible with transient retinal ischemic attack, urgent investigations were initiated. He had normal inflammatory markers but computed tomography angiogram of the brain and neck demonstrated a large plaque in the ipsilateral internal carotid artery. Double anti-platelet therapy was started and stenting of the involved carotid artery was performed. The patient was symptom-free at the last follow-up. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Patients with retinal ischemia as the etiology of TMVL are at high risk of cardiovascular events and death. Their risk of cerebrovascular accidents is highest within 48 h from the episode of TMVL, thus they should have an urgent ophthalmologic examination and, if it is unrevealing, inflammatory markers should be checked and an urgent stroke prevention protocol should be initiated. Appropriate management with medical or surgical interventions significantly reduces morbidity and mortality in these patients.

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.