Sympathetic Endophthalmitis-An eye emergency
Its incidence has declined markedly with the use of microsurgical techniques and use of potent steroids.With microsurgical techniques eye is meticulously repaired.
Its exact etiology is unknown.The predisposing factors are as follows:
1)Penetrating injury:sympathetic endopthalmitis is almost always occurs after a penetrating injury.
2)Ciliary region wounds:This region is called as dangerous zone.Any injury here predisposes the person to sympathetic endopthalmitis.
3)Wounds with incarceration of the ciliary body,iris,lens capsule are vulnerable.
4)It is commoner in children as compared to adults
5)It does not occur if there is actual suppuration in the injured eye.
There are many theories for it but the most accepted theory is "Allergic theory".This theory says that the uveal pigment antigens act as an allergen thus excites plastic uveitis in the fellow normal eye.
There is granulomatous uveitis.This means there is nodular aggregation of lymphocytes,epitheloid cells,plasma cells and giant cells.There is formation of "Dalen-Fuchs nodule".These nodules are formed due to proliferation of pigment epithelium of ciliary body,iris and choroid which is associated with lymphocyte and epitheloid cellular invasion.The retina shows sympathetic perivasculitis i.e. cellular infiltration around vessels.
I) Exciting(injured) eye:
There are features of persistent low grade plastic uveitis.This includes lacrimation,ciliary congestion and tenderness.There are keratic precipitates present at the back of cornea.This is a dangerous sign
II) Sympathizing(sound) eye:
It is usually involved after time period of 4-8 weeks of injury in the fellow eye.Earliest case reported was after 9 days of ocular injury but mostly cases occur within the first year of injury.However there may be delayed and very late cases.It mostly always manifests as acute or plastic iridocyclitis. Very rarely the manifestation may be as neuroretinitis or choroiditis.
Clinically iridocyclitis in sympathizing(fellow) eye can be divided into two stages:
1) Prodromal stage
Symptoms:The earliest symptoms are increased sensitivity to light(photophobia) and transient indistinctness of the near objects which is due to weakening of accommodation mechanism.
Signs:The first sign might be the presence of retrolental flare or a few keratic precipitates(KPs) on the back of cornea.Other signs can be ciliary congestion(mild),mild tenderness of the eye globe,fine vitreous haze and optic disc oedema.
2) Fully developed stage:It is clinically seen by signs and symptoms of acute plastic iridocyclitis.