The Path to High Pressure: Stages and Symptoms of NVG

Neovascular glaucoma (NVG) does not happen all at once. It is a progressive disease that moves through distinct phases as the eye attempts to compensate for a lack of oxygen ^[1]. In the early stages, the condition is often “silent,” meaning you may not feel any pain or notice vision loss until the damage is advanced ^[1][2].

The Four Stages of NVG

Understanding which stage you are in helps your doctor determine the most effective treatment plan.

1. Prerubeosis (The Silent Phase)

At this earliest point, the eye is starved for oxygen, but no new vessels are visible yet ^[1]. There are typically no symptoms during this stage. The pressure in the eye remains normal, but the biological “SOS” signals (VEGF) are starting to build up ^[3].

2. Preglaucoma: Rubeosis Iridis

In this stage, tiny, abnormal blood vessels begin to appear on the surface of the iris (the colored part of the eye) and around the pupil ^[1][3].

• Mechanics: Vessels are present, but they haven’t yet reached the drainage angle.
• Symptoms: Most patients still have no symptoms and normal eye pressure, though a doctor can see these vessels during a dilated exam ^[1].

3. Open-Angle Glaucoma

The abnormal vessels have now grown into the drainage angle—the area where fluid leaves the eye ^[1].

• Mechanics: A thin, invisible membrane of fibrovascular tissue grows over the drain (the trabecular meshwork), acting like a layer of plastic wrap that prevents fluid from exiting ^[3].
• Symptoms: Eye pressure begins to rise. You may experience mildly blurred vision or a dull ache, though some people still feel nothing at this point ^[4].

4. Angle-Closure Glaucoma

This is the most advanced and urgent stage. The abnormal membrane contracts, pulling the iris forward and “zipping” the drain shut ^[1][3]. This creates permanent scars called peripheral anterior synechiae (PAS) ^[3][5].

• Mechanics: The drainage angle is physically closed. Fluid is trapped, causing pressure to skyrocket.
• Symptoms: Severe eye pain, a “steamy” or cloudy cornea, redness, and significant vision loss ^[6][4].

How NVG is Diagnosed

To determine your stage, your doctor will perform several specialized tests:

• Gonioscopy (The Gold Standard): This is the most important test for NVG ^[7]. The doctor places a special mirrored contact lens on your eye to look directly at the drainage angle ^[8]. This is the only way to see if vessels are growing in the drain or if PAS (scars) have begun to form ^[5].
• Slit-Lamp Exam: A high-powered microscope used to check for rubeosis (vessels on the iris) ^[1].
• AS-OCT (Anterior Segment OCT): This is a non-invasive, high-resolution “ultrasound-like” image of the front of the eye ^[9]. It allows doctors to see the physical shape of the drainage angle and measure how much it has narrowed ^[10][11].

Early diagnosis in the first two stages is critical because it allows doctors to stop the “SOS” signal before the drainage angle is permanently scarred shut ^[12][2].