NEOVASCULAR GLAUCOMA

Secondary Glaucoma due to fibrovascular membrane on the surface of the iris and the angle.

Thrombotic glaucoma, hemorrhagic glaucoma,

rubeotic glaucoma.

Nettleship et al noted an association between Neovascular glaucoma and diabetes mellitus.

Kurtz described the gonioscopic appearance of

new vessels at the angle and a fibrovascular contracted to form PAS in 1937.

The term Neovascular glaucoma was proposed by Weiss et al in 1963.

RUBEOSIS IRIDIS New vessels arise from the microvascular bed

in the iris and ciliary body.

Appearance as endothelial buds from capillaries of minor arterial circle as tufts.

Fibrous membrane contains myofibroblasts that have contractile properties.

Pulls the posterior pigment layer of the iris epithelium anteriorly - ectropion uvea

Pulls the peripheral iris into the chamber angle producing PAS.

PATHOGENESIS

CHRONIC RETINAL ISCHAEMIA

ANGIOGENIC FACTORS RELEASED & DIFFUSED

NEOVASCULARISATION ON IRIS AND IN THE ANGLE.

NEOVASCULAR GLAUCOMA

CAUSES

Ischaemic Central retinal vein occlusion Diabetic Retinopathy Retinal detachment Chronic uveitis Malignant melanoma Retinoblastoma Cataract excision Vitrectomy

PRESENTATION

SYMPTOMS - Sudden pain - Headache ,vomiting - Redness - Watering - Defective vision - Photophobia

SIGNS

Ciliary injection Hazy cornea from epithelial edema Deep anterior chamber with moderate

flare, Hyphema, a small pupil, and new vessels

on the iris and in the angle(Gonioscopy) Ectropion uveae Fixed dilated pupil Raised IOP

NORMAL IRIS VESSELS Uniform size Radial course No branching Located in stroma

NEW VESSELS Irregular size Irregular course Branching Located on surface

TREATMENT

Panretinal photocoagulation Goniophotocoagulation Intra Vitreal Anti -VEGF Mydriatics Corticosteroids Filtering surgeries Cyclodestructive procedures Enucleation

PANRETINAL PHOTOCOAGULATION

Performed by reducing stimulus for new vessel formation.

in Diabetic retinopathy & Ischaemic CRVO.

200 -500 um spot size , 1500 -2000 burns

Use of Argon laser To prevent the onset of NVG.

GONIOPHOTOCOAGULATION

Useful adjunct to panretinal photocoagulation.

Performed directly to NVI before development of NVG ,Absence of synechia.

Low-energy argon laser treatments (0.2 seconds, 50-100 um, 100 - 200 mW) are applied to the neovascular tufts as they cross the scleral spur.

INTRAVITREAL ANTI - VEGF

Bevacizumab (Avastin) at dose of 1.25 mg /0.05 ml .

It inhibits the VEGF – receptor interaction and blocks vascular permeability and angiogenesis.

FILTRATION SURGERIES

Good visual potential,IOP not reduced by medical treatment and if the neovascular membrane has regressed.

To prevent pressure –induced injury to optic nerve and improve vascular perfusion.

To control pressures and preserve vision.

MEDICATIONS

Mydriatics Corticosteroids Topical beta blocker Carbonic anhydrase inhibitor

CYCLODESTRUCTIVE PROCEDURES

In painful eyes ,poor visual potential it is performed to destroy secretory ciliary epithelium,reduces aqueous secretion.

Cyclocryotherapy is usually applied at 60 degrees C to 80 degrees C, using a large-tip probe with its anterior edge 2.5 mm posterior to the limbus. Six to eight 60-second freezes are placed over half of the circumference of the ciliary body.

LASER CYCLOABLATION

12-24 burn spots ,posterior to limbus over 360 degrees , 1500-2000 MW, 1.5-2 secs.

REFERENCES

1. Becker – Shaffer Diagnosis and therapy of the glaucomas , 8 th edition.

2. American academy of Ophthalmology ,Glaucoma , Section 10 , 2011-12.

3. Jack J Kanski and Brad Bowling , Clinical Ophthalmology ,7 th edition.

THANK YOU