Neovascular glaucoma: causes, warning signs and treatment

Glaucoma UK uses the term secondary glaucoma for glaucomas that occur as a side effect of another medical condition or trauma, as opposed to primary glaucoma, where no cause can be identified. In both, the pressure rise and the damage to the optic nerve are the same. Neovascular glaucoma, sometimes called rubeotic glaucoma, is one of the secondary types.

The name means new vessel glaucoma. When parts of the eye are deprived of oxygen they release signals that trigger new, abnormal blood vessels to grow, which the Royal Berkshire leaflet calls neovascularisation. The vessels are fragile, can interfere with the eye's fluid drainage, causing pressure to rise, and may also bleed. Glaucoma UK describes the same mechanism as new vessels growing on the surface of the eye and into the drainage channel, blocking the outflow of the watery aqueous fluid.

The leaflet lists the usual underlying causes: diabetic eye disease (proliferative diabetic retinopathy), retinal vein occlusion (a type of eye stroke) and other conditions that reduce oxygen supply to the eye. In practice this means people with long-standing diabetes, or those who have had a blocked vein in the retina, are the ones most likely to be watched for it.

This is why the leaflet lists managing systemic conditions such as diabetes and high blood pressure as part of treatment, alongside treatment of the retina itself.

Glaucoma UK and Moorfields say that most forms of glaucoma cause no symptoms early. The Royal Berkshire leaflet warns that damage can occur silently and quickly if treatment is delayed or not followed, even if vision seems fine, and that if vision in the eye was already poor, the eye could become painful without timely effective treatment.

The leaflet advises attending eye casualty or calling NHS 111 if you have increasing pain, sudden vision changes, redness or light sensitivity. The NHS says that if symptoms of glaucoma develop suddenly, including intense eye pain, a red eye, tenderness around the eyes, rainbow-coloured circles around lights, blurred vision, feeling or being sick and a headache, you should call 999 or go to A&E, and not drive yourself.

Glaucoma is usually picked up through eye examinations. Glaucoma UK describes the tests used: a visual field test of peripheral vision, an eye pressure test and an assessment of the optic nerve. A specialist repeats these and adds further tests. The Royal Berkshire leaflet's treatment plan page lists the kinds of checks involved in neovascular glaucoma: retinal laser, eye injections, an eye pressure review clinic, a glaucoma clinic and a medical retinal clinic, which reflects that both the retina and the pressure need attention.

The Royal Berkshire leaflet explains that treatment is made up of two critical parts, and that you may not need all of the treatments described.

The leaflet stresses that your active participation is essential: use prescribed eye drops and medicines as directed and attend all appointments, including laser, injections and pressure monitoring. If acetazolamide tablets are prescribed, the leaflet reminds patients to stay well hydrated and keep up their daily potassium intake, within limits if diabetic.

The leaflet says the condition is serious, but that timely and appropriate treatment can save vision or keep the eye pain-free. The NHS and RNIB note that sight already lost cannot be restored, so protecting what remains is the goal. The NHS lists RNIB and Glaucoma UK as sources of information and support for people with glaucoma and sight loss.

Neovascular glaucoma is treated in NHS hospital eye services, with a plan that, in the Royal Berkshire example, spans retinal laser, eye injections, pressure review and glaucoma and medical retinal clinics. Because treatment is time-sensitive, speed to first treatment is the important point. Private ophthalmology can offer quick appointments, but laser, injections and drainage surgery are the same procedures; many people use the NHS for most of the pathway. Ask clearly who is responsible for the retinal treatment and who for the pressure, and where to go urgently if pain or vision changes.