Retinal vein occlusion (RVO) guideline: summary (2023)

Central retinal vein occlusion

Non-ischemic CRVO may resolve without complications. Macular edema (MO) is the most common complication of CRVO and anti-VEGF treatment has been successful in improving vision in eyes with MO secondary to CRVO.

However, 30% of eyes with non-ischemic CRVO can convert to ischemic CRVO within 3 years. Rapid anti-VEGF therapy does not completely prevent deterioration of retinal nonperfusion in the eyes with CRVO [9]. Anti-VEGF therapy in eyes with ischemic CRVO continues to carry the risk of neovascularization and should be closely monitored after discontinuation of anti-VEGF therapy.

occlusion of a retinal vein

In patients with a recent onset of mild visual impairment due to MO secondary to BRVO, it may be useful to monitor disease progression during the first three months of follow-up. However, in some patients presentation may be delayed, and in others with significant visual impairment at the time of presentation, only 18-41% of eyes spontaneously improve in visual acuity, suggesting that visual acuity does not improve to 6/10 on average. 12. In these cases, early treatment may be warranted.

Associations and risk factors

The most common associations of RVO are associated with an increased risk of atherosclerosis and are not significantly associated with systemic venous occlusion or its known risk factors. The main associations of RVO can therefore be defined as risk factors for atherosclerosis and the rest are conditions that cause hyperviscosity or slow or turbulent flow through retinal veins.

Diabetes is no more common in patients with RVO than in the general population. However, testing for diabetes is helpful in diagnosing RVO to detect undiagnosed diabetes. The NICE recommended target HbA1C for type 2 diabetes without hypoglycaemia is 48 mmol/mol (6.5%) (NICE NG28, 2015, updated 2021).

Anti-phospholipid antibody testing is not recommended for RVO isolated from other recognized clinical associations with anti-phospholipid syndrome (APS). There is currently no high quality evidence to support the use of anticoagulants or antiplatelet agents in the treatment of RVO [10]. Finding a thrombophilic abnormality in a patient with RVO does not change treatment options or prognosis.

Cardiovascular morbidity and mortality

The systemic diseases for which a patient with RVO may be at higher risk are:

• Stroke: Conflicting reports from associations have been noted (see below) [11,12,13,14].

• One study found cardiovascular disease under the age of 70 [13], but not in another report [5].

• Peripheral venous disease is observed in (13/439) 3% before the diagnosis of CRVO [15].

This does not necessarily mean that CRVO poses a risk for these conditions, but rather that RVO and these conditions share common risk factors, such as hypertension and diabetes. There is no clear evidence that a different therapeutic approach for medical risk factors after RVO is justified than is already recommended.

RVO in younger patients (<50 years)

RVO can occur in young patients with an estimated global prevalence of 0.26% in people aged 30-39 and 0.44% in people aged 40-49.16]. The need for intravitreal anti-VEGF for MO is lower in young patients with CRVO [17,18]. However, at least 20% of patients develop poor vision with severe neovascular complications [19].

Medical investigations of retinal vein occlusions

The main benefit of medical testing in RVO is to improve health by treating the commonly associated risk factors of atherosclerosis, hypertension, diabetes and lipid abnormalities.

Summary of the recommended medical examinations in the eye clinic:

• medical history

• measurement of blood pressure

• Estimation of serum glucose level

• Request lab tests for FBC and ESR

Further evaluation of possible comorbidities, including further medical examination, is probably best done by the patient's physician, who can then organize further management and support measures, such as smoking cessation.

The decision to continue estrogen-containing therapies in a woman with RVO must be made on a case-by-case basis.

Retinal imaging in RVO

• OCT is recommended for the diagnosis, monitoring and assessment of treatment response to MO secondary to RVO

• FA/OCTA is recommended to assess retinal non-perfusion to help identify eyes with ischemic CRVO

Ophthalmic management of CRVO

• Intravitreal injections of approved anti-VEGF or dexamethasone implants are the recommended treatment for MO secondary to CRVO, based on physician and patient choice, taking into account frequency of treatment, risk of IOP elevation, and formation of cataract.

• Just over a third of patients require only three anti-VEGF injections to reach maximum VA, while another third require six consecutive anti-VEGF injections. It is recommended to start treatment according to the dose, i.e. H. monthly anti-VEGF treatment until maximal stable VA is reached.

• As part of PRN therapy, it is recommended that these patients be monitored at 4 to 8 week intervals and treated appropriately to achieve optimal visual outcomes.

• Delaying the start of treatment by up to 6 months resulted in smaller visual improvements compared to starting treatment immediately. It is therefore imperative that patients begin treatment as soon as the diagnosis is made, unless the treating physician and/or patient chooses to delay treatment.

• Patients with VA <6/96 should be carefully considered for further treatment in those eyes whose visual acuity or central subfield thickness of the OCT does not improve after three injections at monthly intervals. Treatment is not recommended if no response occurs after six injections. Several factors, such as the degree of macular ischemia, structural damage to the fovea and other confounding factors, should be considered in deciding whether to continue treatment after initial therapy in this patient population.

• In patients treated with intravitreal dexamethasone, monitoring and possible monitoring of intraocular pressure and the risk of developing cataracts should be considered.

• There is also no evidence that a combination of macular lattice laser or pan-retinal photocoagulation and intravitreal anti-VEGF or steroids is beneficial in MO secondary to CRVO.

Treatment of macular edema in ischemic central venous occlusion

• Eyes with posterior pole nonperfusion greater than 10 DA should not be excluded from intravitreal therapy.

• In eyes with a vision of 6/96 or worse (eyes excluded from clinical trials), anti-VEGF should still be considered if significant MO is present, as reasonable improvements in vision may still occur. However, if the edema resolves after an anti-VEGF study without improvement in visual acuity, it is recommended to stop after three injections.

• In eyes with ischemic CRVO, a one to two month observation for neovascularization is recommended in the first year after discontinuation of anti-VEGF therapy.

• In eyes undergoing dexamethasone implantation, early detection of iris neovascularization is critical to treatment.

Management of ischemic central retinal vein occlusion and anterior segment neovascularization

• Monitor ischemic CRVO monthly for new iris and/or angular vessels [6] unless there are specific risk factors.

• Vascular endothelial growth factor inhibitors (anti-VEGF agents) can be used as adjuvants for panretinal photocoagulation in patients with anterior segment neovascularization secondary to ischemic CRVO.20].

• Initiate anti-VEGF therapy at the first sign of new iris or angular vessels, followed by adequate panretinal photocoagulation, either on the same day (before anti-VEGF therapy) or within 1-2 weeks.

Management of established neovascular glaucoma

• If the eye has visual potential, intraocular pressure should be controlled with topical antihypertensive drugs, surgery, or cycloablative procedures. In addition, long-term regression of NVI and NVA seems to offer an opportunity to maintain ocular comfort.

Further follow-up in eyes with significant ischemia

• Monthly follow-up is recommended during the first 6 months and after 6 months, follow-up should be every 3 months for a year.

• Subsequent follow-up for all patients depends on the treatment undertaken and complications in the earlier period, but is usually not necessary after 3 years in uncomplicated cases.

• The development of intervertebral discs + spontaneous resolution of the MO indicates a good outcome and should lead to discharge from clinical surveillance after 6 months, provided no other complications arise.

BRVO Ophthalmic Management

• The recommended treatment for MO due to BRVO is an approved anti-VEGF or dexamethasone implant, based on physician choice, taking into account frequency of treatment, risk of IOP elevation and cataract formation, and under subject to consultation with the patient.

• If laser photocoagulation is considered, it should be performed in eyes with MO secondary to BRVO of at least 3 months and a visual acuity of 6/12 or worse and without significant macular bleeding and with a fluorescein angiogram showing capillary perfusion in the absence of blood . affecting the fovea. However, based on these recommendations, only a minority of patients in clinical practice are eligible for this treatment option.

• Treatment of neovascularization:

  • Neovascularization of the intervertebral disc or retina is indicative of ischemic photocoagulation of the retina (sectoral photocoagulation), although available evidence suggests that waiting for vitreous haemorrhage before laser treatment does not adversely affect vision prognosis.17].

  • In patients with retinal ischemia in one or more quadrants, follow-up visits at 3 to 4 month intervals are recommended.

  • Apply sector laser photocoagulation as soon as retinal or optic disc neovascularization occurs.

  • Fluorescein angiography is usually not necessary prior to laser treatment, as the area of ​​ischemia is clinically visible.

• Photocoagulation for retinal neovascularization in BRVO is applied in the area of ​​retinal capillary occlusion. A sufficient number of laser points should be applied to the affected area, using a single-point or multi-sport laser, spaced one shot apart and with enough energy to cause a slight off-white laser staining of the retina. A quadrant usually requires a minimum of 500 exposures with a diameter of 500 µm.

RVO Performance Specifications

• The time from referral by the primary source to the initial examination and treatment by the ophthalmologist at the eye clinic is a maximum of 2-4 weeks from presentation.

• Minimal clinical services required for effective treatment

  • Visual acuity assessment in ETDRS letters.

  • Color fundus photographs and fundus fluorescence angiography (FFA)/OCT-A by trained technical personnel

  • Optical coherence tomography (OCT) with the SD-OCT by trained specialists

  • Treatment is started within 1-2 weeks after assessment by the treating ophthalmologist

  • Suitable facilities for IVT injection

  • Sufficient capacity for follow-up, monitoring and retreatment

• Referral paths:

  • All patients suspected of having RVO by the optometrist, GP or other health professional should be referred directly to the nearest eye centre, with routes established to allow for urgent access.

  • Optometrists can perform a 'screening' or initial examination on patients suspected of having RVO.

  • Rapid clinics can be set up that perform community or hospital imaging to assess people who are symptomatic, visually impaired and centered with MO.21].

• Visual impairment and living with RVO:

  • Patients with reduced BCVA due to RVO should have early access to support and advice for visual impairments.

  • Don't wait until all treatment options have been explored or until a person's vision has deteriorated to a level that requires registration as visually impaired/severely visually impaired before referring someone to visually impaired and rehabilitation services.

The full retinal vein occlusion policy is available on the website of the Royal College of Ophthalmologists:https://www.rcophth.ac.uk/resources-listing/retinal-vein-occlusie-rvo-guidelines/