SN5 SHORT NOTE 5M ★ High-yield

Describe neovascular glaucoma with its causes and management.

Ophthalmology · 3rd Professional

Neovascular glaucoma is a severe secondary glaucoma caused by the growth of a fibrovascular membrane over the iris and the angle, driven by VEGF released from ischaemic retina.
It is one of the most destructive and most difficult of all glaucomas.
The essential concept is that it is a retinal disease presenting in the anterior segment. Ischaemic retina releases vascular endothelial growth factor.

Stage	Findings and treatment
1. Rubeosis IRIDIS (pre-glaucoma)	Fine, tortuous new vessels at the pupillary margin and in the angle. The pressure is still normal and the angle open. Note: new vessels often appear in the angle before the iris, so gonioscopy is essential and examining the iris alone will miss them. This is the stage at which the disease is reversible
2. Open-angle secondary glaucoma	The fibrovascular membrane covers the trabecular meshwork and obstructs it while the angle is still anatomically open. The pressure rises. Gonioscopy shows vessels crossing the scleral spur — which is abnormal.
3. Angle-closure (synechial) glaucoma	The myofibroblasts in the membrane contract, dragging the iris over the angle to form peripheral anterior synechiae, and pulling the pigment epithelium around the pupil margin to produce ectropion uveae. The angle zips closed circumferentially, the pressure becomes very high, and the eye is painful, congested and often blind

Treatment has two separate objectives, and both are needed: abolish the ischaemic drive, and control the pressure. Treating the pressure alone fails
Panretinal photocoagulation (PRP) is the definitive treatment, because it destroys ischaemic retina and so removes the source of VEGF permanently. It should be applied urgently and completely, and repeated if rubeosis persists
Anti-VEGF injection (bevacizumab, ranibizumab) causes dramatic and rapid regression of new vessels within days, which is invaluable — but the effect is temporary, lasting some weeks, and it does not address the ischaemia. It is therefore used as a bridge: to clear the eye, quieten the angle and permit laser or surgery. Anti-VEGF without PRP is a trap, since the vessels return
Where the media are opaque — vitreous haemorrhage, cataract, corneal oedema — PRP cannot be delivered, and trans-scleral or endoscopic cyclophotocoagulation, or PRP at vitrectomy, is used instead

All questions in Glaucoma