Neovascular Glaucoma: Exam Essentials

Master neovascular glaucoma for boards: VEGF pathophysiology, the 90-day CRVO rule, rubeosis stages and why PRP beats IOP drops alone.

Reviewed for accuracyJuly 27, 20262 min read

Three-stage diagram of neovascular glaucoma showing: Stage 1 rubeosis iridis with fine new vessels at the pupillary margin, Stage 2 open-angle NVG with new vessels crossing the trabecular meshwork and a visible open angle, and Stage 3 angle closure with peripheral anterior synechiae pulling the iris forward and sealing the angle shut. Pathophysiology banner shows: Retinal ischemia → VEGF → Neovascularization → Angle Closure.

Warm-up

In neovascular glaucoma, the underlying retinal problem is often:

Lesson

Neovascular Glaucoma in 30 Seconds

Neovascular glaucoma is a secondary glaucoma caused by retinal ischemia that drives VEGF-mediated neovascularization of the iris and angle. It is dangerous because the new vessels and fibrovascular membrane can close the angle and produce rapid, severe and often irreversible pressure damage.

What Causes Neovascular Glaucoma

Retinal ischemia upregulates VEGF, which diffuses through the aqueous into the anterior segment and triggers neovascularization of the iris and angle. The resulting fibrovascular membrane contracts, closes the angle and causes secondary angle-closure glaucoma. The most common causes are ischemic central retinal vein occlusion and proliferative diabetic retinopathy, often preceded by severe nonproliferative diabetic retinopathy. Ocular ischemic syndrome and, less commonly, central retinal artery occlusion may also lead to neovascular glaucoma.

Stages and Clinical Features

Rubeosis iridis: fine new vessels on the iris surface, first at the pupillary margin. On slit lamp this may be subtle before angle involvement is obvious.
Open-angle stage: fine neovascularization crossing the scleral spur with an associated fibrovascular membrane. The angle remains open without extensive peripheral anterior synechiae on gonioscopy.
Angle-closure stage: membrane contraction, peripheral anterior synechiae and a closed angle. This stage usually presents with uncontrolled IOP and advanced disease.

4 Facts Exams Always Ask

VEGF is the main driver of neovascularization in neovascular glaucoma.
Approximately one-third of eyes with ischemic CRVO develop anterior segment neovascularization, often within 90 days, placing them at high risk for neovascular glaucoma.
Anti-VEGF rapidly suppresses VEGF-mediated neovascularization, while panretinal photocoagulation reduces the underlying retinal ischemic stimulus and provides longer-term control. Anti-VEGF acts quickly but temporarily; PRP provides the definitive treatment of the ischemic retina.
Gonioscopy is high yield because it can detect angle neovascularization before peripheral anterior synechiae and permanent closure form.

The Classic Trap

The common exam mistake is treating neovascular glaucoma as only a pressure problem. IOP-lowering drops may help temporarily but do not remove the ischemic stimulus. Definitive control requires treatment of the retinal ischemia with panretinal photocoagulation and anti-VEGF therapy. Once broad peripheral anterior synechiae develop, angle closure is largely irreversible.

Clinical Pearl

Gonioscopy is the exam that catches neovascular glaucoma before it becomes fixed. If you see iris neovascularization or angle vessels early, you can intervene before peripheral anterior synechiae lock the angle shut. Once extensive synechiae form, the angle closure is largely irreversible and outcomes are significantly worse.

Check yourself

Checkpoint 1

Which anterior segment finding may precede angle closure in neovascular glaucoma?

Checkpoint 2

What is the key treatment aimed at the underlying cause of neovascular glaucoma due to retinal ischemia?

Clinical case

A 63-year-old man had an ischemic central retinal vein occlusion 3 months ago. He now presents with fine new vessels at the pupillary margin, neovascularization crossing the scleral spur on gonioscopy and elevated IOP. The angle remains open without extensive peripheral anterior synechiae.

In neovascular glaucoma secondary to central retinal vein occlusion, what is the primary molecular driver of iris and angle neovascularization?

Explanation

Retinal ischemia upregulates VEGF, which diffuses anteriorly into the aqueous and drives neovascularization of the iris (rubeosis iridis) and angle, ultimately causing peripheral anterior synechiae and angle closure. PEDF is actually an anti-angiogenic factor that is typically decreased in ischemic states, opposite to the correct mechanism.

Case discussion

This is pre-synechial (open-angle) neovascular glaucoma. Retinal ischemia from the ischemic CRVO has driven VEGF-mediated anterior segment neovascularization, appearing at the classic 90-day window. Treatment must address the ischemic source: anti-VEGF for rapid regression of neovascularization and panretinal photocoagulation for definitive long-term control of the retinal ischemic stimulus, alongside IOP management.

Sources & Reviewer Info

Reviewed by Vasilis Inglezis: Optometrist and Ocular Oncology Imaging Specialist, Ocular Oncology Center, Athens, Greece. Last updated July 27, 2026.

Diagram created with AI image generation, clinically reviewed for accuracy.

References

American Academy of Ophthalmology. Basic and Clinical Science Course, Section 10: Glaucoma.
Shields' Textbook of Glaucoma.
American Academy of Ophthalmology. EyeWiki: Neovascular Glaucoma.

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