Synechiae [eye]

Causes and risk factors

Synechiae can present as anterior adhesion or posterior adhesion. Adhesion of iris to the cornea is called as anterior synechia while adhesion of iris to lens capsule or vitreous chamber is called as posterior synechia. Causes of anterior synechia include perforated corneal ulcer, penetrating injury, angle closure glaucoma, iridocyclitis. Causes of posterior synechiae is iridocyclitis. Adhesions cause blockage of flow of aqueous humour from posterior to anterior chamber. Synechiae is caused due to various reasons such as following trauma after a sports injury, severe blow to the eye or head injury or accidents. It can result from a systemic disease or ocular disease or infection. It is caused as a result of rheumatological disease and inflammatory syndromes. It can occur as a result of major eye surgery. Synechiae can result from diseases like glaucoma, uveitis, keratitis, etc.

Clinical presentation

Patient presents with ocular pain, headache, blurred vision, and halos. Anterior synechiae causes closed angle glaucoma. In closed angle glaucoma, the drainage angle formed by the cornea and the iris becomes blocked or too narrow due to adhesion of the iris. As a result, aqueous fluid cannot adequately flow through and exit the eye, causing an abrupt rise in intraocular pressure. Posterior synechiae causes adhesion of iris to lens capsule blocking the flow of aqueous humour from flowing through posterior chamber to anterior chamber again raising the intraocular pressure. Symptoms of glaucoma are seen in synechiae like narrowing of vision [tunnel vision], loss of vision, redness in the eye, hazy eye. Patient complains of pain in the eye along with symptoms such as nausea and vomiting.

Investigation

Medical history by the patient and clinical examination by the ophthalmologist helps in diagnosis. Tonometry in which the pressure within the eye [intraocular pressure] is measured. Ophthalmoscopy is advised. Visual field testing is recommended. Measurement of visual acuity is done. Gonioscopy is done to inspect the drainage angle.

Treatment

The treatment is focused on complete dilatation of pupil which prevents adhesions of iris. Treatment involves use of mydriating [causing dilatation of pupil] agents which prevent formation of posterior synechiae. Keeping the intraocular pressure within normal limits also help in treating the condition. Corticosteroid eye drops are useful.