BASICS

DESCRIPTION

• Glaucoma caused by neovascularization of the angle and pupillary margin with contraction of myofibroblasts. This leads to peripheral anterior synechiae and eventual angle closure glaucoma.

• In the early stages, the abnormal blood vessels can regress after panretinal laser (PRP) or Bevacizumab treatment.

• In later stages, when fibrovascular ingrowth and contraction of the drainage angle occur, medical therapy becomes less effective for intraocular pressure control.

• Synonym(s): Hemorrhagic glaucoma, congestive glaucoma, rubeotic glaucoma, and thrombotic glaucoma.

EPIDEMIOLOGY

Incidence

• Rare

• Increased in diabetic patients after lens removal and vitrectomy or any breach in the posterior capsule.

Prevalence

• More prevalent in elderly patients

• Prevalence of neovascular glaucoma (NVG) in diabetes is overall 2%, but 21% of those with proliferative diabetic retinopathy.

• 23–33% of patients with ischemic central retinal vein occlusion (CRVO) develop NVG with the prevalence of CRVO ranging from 0.1–0.7%.

RISK FACTORS

• Any process that involves retinal ischemia (see Etiology section).

• The most frequent risk factors are the presence of a CRVO or proliferative diabetic retinopathy.

PATHOPHYSIOLOGY

• Retinal hypoxia causes production of factors promoting angiogenesis including vascular endothelial growth factor (VEGF).

• New blood vessels form in the anterior and posterior segment following chronic retinal ischemia.

ETIOLOGY

• Central retinal vein occlusion (CRVO)

• Proliferative diabetic retinopathy

• Carotid artery occlusive disease

• Central retinal artery occlusion (CRAO)

• Branch retinal vein occlusion

• Intraocular tumor

• Chronic retinal detachment

• Uveitis-glaucoma-hyphema syndrome

• Chronic or severe ocular inflammation

• Radiation retinopathy

• Coats disease

• Sickle cell retinopathy

• Eales disease

• Retinopathy of prematurity

• Carotid-cavernous fistula

• Takayasu disease

• Giant cell arteritis

• Anterior segment ischemia (previous strabismus surgery)

• Trauma

COMMONLY ASSOCIATED CONDITIONS

• Diabetes

• High blood pressure

• Atherosclerotic disease

DIAGNOSIS

HISTORY

• Red, painful eye

• Pressure sensation

• Photophobia

• Decreased vision

PHYSICAL EXAM

• New blood vessels at the pupillary margin

• Gonioscopy- new blood vessels in angle or hyphema

• Indirect ophthalmoscopy- look for the underlying cause:

– CRVO- venous engorgement, retinal hemorrhages, disc swelling, cotton wool spots, and macular edema

– Long-standing ischemia – optociliary shunt vessels

– Choroidal Tumors

– Retinoblastoma (in kids)

– CRAO-cherry red spot

– Proliferative diabetic retinopathy

– Ocular ischemic syndrome- midperipheral hemorrhages, central retinal artery collapses with mild digital pressure on the globe

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Depends on etiology:

• Fasting glucose, Hemoglobin A1c

• Blood pressure, cholesterol

• ESR (anyone >50 yrs old with CRAO or suspected autoimmune/inflammatory disease)

• Hyperviscosity workup- young patients with CRVO

Imaging

Initial approach

• Fluorescein angiography- to further delineate the underlying cause and the amount of neovascularization and retinal ischemia

(^∗to assess ischemic versus nonischemic CRVO)

• B-scan, if no view of posterior fundus to eliminate tumors as the etiology of rubeosis

• ERG- can be used to assess retinal ischemia when there is no view of the fundus due to lens opacity

• Carotid ultrasound/echocardiogram- in CRAO and ocular ischemic syndrome

Follow-up & special considerations

• Gonioscopy/examination every month for the first 4 months after CRVO, since rubeosis classically appears 3 months after ischemic CRVO in 50% of eyes and 80% appears in the first 6 months

• Monthly follow-up needed for nonischemic CRVO since 15% of nonischemic CRVO converts to ischemic CRVO within 8 months and 33% convert in 3 years.

DIFFERENTIAL DIAGNOSIS

• Uveitic glaucoma

• Fuchs heterochromic iridocyclitis

TREATMENT

MEDICATION

• Anti-VEGF (anti-vascular endothelial growth factor) intravitreal injections with PRP (1)[B], (2)[B]

– Avastin (Bevacizumab)

– Macugen (Pegaptanib sodium)

– Lucentis (Ranibizumab)

(either 1 mg/0.05 mL, 1.25 mg/0.05 mL, or 2.5 mg/0.05 mL)

• Aqueous suppressant eye drops: Beta blockers, topical and oral carbonic anhydrase inhibitors (Diamox), Brimonidine

• Contraindicated- Pilocarpine

• Steroid drops for the inflammatory response

• Atropine (cycloplegics)-decrease ocular congestion and prevent ciliary muscle spasm

ADDITIONAL TREATMENT

General Measures

• Limiting carbohydrates in diabetics

• Limiting salt intake in hypertensive patients

Issues for Referral

Retinal specialist- for PRP and Avastin

SURGERY/OTHER PROCEDURES

• Panretinal photocoagulation (PRP)-can be done with slit lamp laser, indirect laser, or endolaser at the time of vitrectomy (1)[A] 1500–2000 burns with 500 micron spot size.

Argon, Krypton, or Diode laser (Krypton and Diode better with media opacities or blood)

Central Retinal Vein Occlusion Study (3)[A]-PRP if ischemic CRVO caused 2 clock hours of iris neovascularization or any angle neovascularization.

• Trabeculectomy with Mitomycin C-possible, if eye is quiet 1 month after PRP/medical therapy; 61% qualified success rate with concurrent Avastin intravitreal injection (2)[B]

• Tube shunt with patch graft

– Ahmed (S2 or FP): Especially if history of multiple surgeries; success rates vary in the literature but Netland et al. had a 73.1% success rate at 1 year that decreased to 20.6% at 5 years (4)[B].

– Baerveldt tube shunts vary in success as well, with Sidoti et al. showing a 56% success rate at 18 months (5)[B].

• CPC (cyclophotocoagulation) (Diode or Nd:YAG transscleral laser): If poor visual potential or poor surgical candidate

• Endocyclophotocoagulation- similar to CPC but done through an intraocular approach

• Radiation or enucleation for tumor-associated rubeosis

IN-PATIENT CONSIDERATIONS

Initial Stabilization

• Diabetes or blood pressure control prior to surgery

• Treatment of hypercoagulable states if present

Admission Criteria

Inpatient admission required only in those patients who have uncontrolled systemic medical conditions.

Nursing

IV insertion and EKG monitoring perioperatively and when IV mannitol is used to decrease vitreous volume.

Discharge Criteria

Once systemic medical conditions are controlled

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• Frequent follow-up is scheduled depending on the patient’s response to medical glaucoma therapy.

• If guarded filtration surgery or tube shunt is indicated, then standard postoperative care is followed depending on the patient’s clinical response and amount of filtration.

DIET

• Blood pressure, blood glucose, and cholesterol control

• Anticoagulation and antiplatelet agents in those at risk for stroke

PATIENT EDUCATION

• The importance of preventive medicine and routine follow-up with the patient’s internist

• The need for at least routine yearly ophthalmologic examinations in patients >50 years and in all diabetics to improve prognosis with early diagnosis and treatment.

PROGNOSIS

Guarded prognosis: Success depends on prevention and treatment of neovascular glaucoma early in its course and the ability to control the underlying disease process.

COMPLICATIONS

• Chronic pain

• Complete loss of vision

• Choroidal effusions

• Suprachoroidal hemorrhage

• Phthisis

• Loss of eye

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