Finally, the ophthalmologist may observe peripheral anterior synechiae (PAS), or adhesions between the iris and trabecular meshwork.The dual presence of glaucoma and uveitis symptoms points to a diagnosis of uveitic glaucoma. Causes
Uveitic glaucoma is a progressive stage of anterior noninfectious uveitis. Patients diagnosed with anterior noninfectious uveitis may also develop glaucoma; in this case the condition is termed uveitic glaucoma. Uveitic glaucoma can arise from the inflammation that occurs in uveitis; from steroid treatment for uveitis; or a combination of both. Uveitis inflammation
The inflammatory response associated with uveitis may lead to glaucoma. Active anterior uveitis flare-ups may develop quickly; in these cases, the inflammation can damage the tissues in the front part of the eye. Anterior uveitis may also be chronic; in these cases, repeated inflammation can cause progressive, accumulating damage to the eye tissues. In all cases — acute one-time episodes, recurrent chronic inflammation or acute-on-chronic inflammation — damage to the eye tissues can cause increased resistance to the outflow of aqueous humour from the eye, which then increases the pressure inside the eye. In some chronic uveitis cases, the pressure inside the eye waxes and wanes due to the uveitis flare-ups.Elevated pressure inside the eye can lead to irreversible optic nerve damage and glaucoma. Steroid treatment for uveitis
Topical corticosteroids are the first-line treatment for an active flare-up of noninfectious anterior uveitis, and the only effective treatment available for active inflammation. However, steroid treatment for uveitis can lead to uveitic glaucoma.
Corticosteroids increase the fluid pressure inside the eye by increasing resistance to the outflow of aqueous humour, which can cause optic nerve damage and glaucoma. Steroid treatment can therefore cause or worsen uveitic glaucoma.Elevated pressure inside the eye typically develops 2 to 6 weeks after starting corticosteroid therapy, but can occur at any time during corticosteroid therapy and may continue for weeks after steroid use has been stopped. According to the Glaucoma Research Foundation, the risk of developing chronic steroid-induced glaucoma increases with every week of steroid use.Around 90% of patients with open angle glaucoma experience a steroid response of elevated intraocular pressure following steroid treatment. Therefore, once uveitis patients have developed uveitic glaucoma, they should ideally avoid steroids wherever possible. Combination of uveitis inflammation and steroid treatment
In some cases, uveitis inflammation and steroid treatment both contribute to elevated pressure inside the eye, which leads to optic nerve damage and glaucoma. Pathogenesis
Uveitic glaucoma as a result of recurring uveitic inflammation
Uveitic glaucoma can develop as a complication of anterior uveitis resulting from the inflammatory response associated with the disease. The inflammatory response can be characterized by occlusion of the trabecular meshwork, or blocking of the tissue that is responsible for draining aqueous humour from the eye. Another characteristic that presents in some patients is peripheral anterior synechiae (PAS), or adhesions between the iris and trabecular meshwork. These two characteristics of the inflammatory uveitic response can lead to an increase in intraocular pressure, and consequently to irreversible optic nerve damage and glaucoma.