Clinical Presentation
Symptoms often include sudden onset of eye pain, redness, photophobia, and tearing. Clinical examination may reveal ciliary injection, fine keratic precipitates (KP), significant anterior chamber flare, a large number of anterior chamber cells, as well as fibrinous exudates, hypopyon, miosis, and posterior synechiae of the iris.
Diagnosis
The diagnosis can be made based on clinical presentation. Since many systemic diseases can cause or are associated with this type of uveitis, identifying the underlying cause and comorbid conditions is important for guiding treatment and predicting prognosis. A comprehensive medical history is necessary, specifically inquiring about symptoms such as lower back pain, swollen or painful joints, urethritis, gastrointestinal abnormalities, respiratory issues, psoriasis, or other skin conditions. These may help identify associated diseases such as ankylosing spondylitis, reactive arthritis, inflammatory bowel disease (IBD), psoriatic arthritis, tuberculosis, or syphilis. Laboratory investigations may include a complete blood count, erythrocyte sedimentation rate (ESR), and HLA-B27 typing. In cases suspected to be caused by infectious pathogens, specific microbial tests should be conducted.
Differential Diagnosis
Acute Conjunctivitis
This condition has an acute onset and is associated with a foreign body sensation, burning, and abundant discharge. Clinical findings include eyelid swelling and conjunctival hyperemia, which are distinctly different from the photophobia, tearing, blurry vision, ciliary injection, and anterior chamber inflammation seen in acute anterior uveitis.
Acute Angle-Closure Glaucoma
This condition also exhibits acute onset, featuring sudden vision loss, headache, nausea, vomiting, corneal epithelial edema, corneal haze, a shallow anterior chamber, and anterior chamber flare. However, there are no inflammatory cells in the anterior chamber, the pupil is elliptically dilated, and intraocular pressure is elevated. These characteristics differentiate it from acute anterior uveitis, in which the cornea remains clear, there are numerous keratic precipitates, the anterior chamber depth is normal, the aqueous humor contains inflammatory cells, the pupil is constricted, and intraocular pressure is normal or low.
Differentiation from Pan-Uveitis Presenting with Anterior Uveitis Features
Certain types of uveitis, such as Behçet’s disease and Vogt-Koyanagi-Harada disease, can manifest as anterior uveitis during specific stages. However, these conditions are often accompanied by extraocular manifestations, requiring careful consideration during the diagnostic process.
Treatment
The therapeutic principles involve prompt pupil dilation to prevent or break newly formed posterior synechiae and rapid anti-inflammatory treatment to prevent ocular tissue damage and complications. Since the majority of anterior uveitis cases are caused by noninfectious factors, antibiotic therapy is generally not required, unless infectious pathogens are suspected or confirmed. For noninfectious uveitis, effective drug concentrations can usually be achieved in the anterior segment through local application, meaning systemic medications are often unnecessary. However, in cases of severe anterior chamber inflammation, periocular injections or short-term systemic administration of glucocorticoids may be considered.
Cycloplegic Agents
These are essential medications for treating acute anterior uveitis and should be administered as soon as possible following diagnosis. The objectives include:
- Preventing and breaking posterior synechiae of the iris to avoid complications.
- Relieving spasms of the ciliary muscle and pupillary sphincter to reduce congestion, edema, and pain, thereby facilitating inflammation resolution and alleviating discomfort.
Commonly used cycloplegic agents include Homatropine ophthalmic ointment (1%, 2%, 4%), which provides effects lasting 18–36 hours and keeps the pupil in a state of constant movement, effectively preventing posterior synechiae. While the cycloplegic and mydriatic effects of Homatropine are not as long-lasting as Atropine, the prolonged mydriasis and ciliary muscle paralysis induced by Atropine (lasting 10–14 days) may result in a fixed dilated pupil and posterior synechiae, causing more severe consequences. For severe cases of acute anterior uveitis, it is recommended to apply 1%–2% Atropine ophthalmic ointment once or twice daily for a few days. Once inflammation subsides, the treatment can transition to 2% Homatropine ophthalmic ointment, applied once or twice daily. If fresh posterior synechiae are difficult to disrupt, subconjunctival injections of a mydriatic mixture (e.g., 1% Atropine, 1% Cocaine, 0.1% Epinephrine, mixed in equal proportions) at a dose of 0.1–0.2 ml may be considered. For mild inflammation or during the recovery phase, 0.5%–1% Tropicamide eye drops can be administered once daily.
Glucocorticoid Eye Drops
Commonly used formulations include hydrocortisone acetate (0.2%, 2.5%), dexamethasone acetate (0.1%), prednisolone acetate (0.12%, 0.125%, 0.5%, 1%), and dexamethasone sodium phosphate (0.1%) suspension or solution. For severe acute anterior uveitis, 0.1% dexamethasone sodium phosphate solution may be applied every 15 minutes for four consecutive doses, followed by hourly applications for several days. The frequency of application is then gradually reduced based on the resolution of inflammation, and a less potent glucocorticoid eye drop is subsequently used.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
NSAIDs exert anti-inflammatory effects by blocking arachidonic acid metabolites such as prostaglandins and leukotrienes. It has been demonstrated that inflammation following surgery or trauma is caused by arachidonic acid metabolites, and NSAID eye drops can be administered 3 to 6 times daily to treat such inflammation. Oral NSAID treatment is generally unnecessary.
Periocular and Systemic Glucocorticoid Treatment
For patients with corneal epithelial lesions, where glucocorticoid eye drops are contraindicated, subconjunctival injection of dexamethasone can be used. In cases involving reactive optic disc edema or cystoid macular edema, dexamethasone (2.5 mg) can be administered via posterior sub-Tenon's capsule injection. For those who are not suitable for posterior sub-Tenon's injection or those with bilateral acute anterior uveitis presenting with reactive macular edema or optic disc edema, oral administration of prednisone may be considered. The initial dosage is typically 20–30 mg, taken as a single dose in the morning. The dosage is reduced after one week, with the general treatment duration ranging from 2 to 4 weeks.
Systemic Immunosuppressive Therapy
In cases involving systemic conditions, a combination of glucocorticoids and other immunosuppressive agents may be considered. Treatment with anti-tumor necrosis factor (anti-TNF) antibodies may be provided based on the underlying associated disease.
Treatment of Complications
Secondary Glaucoma
Intraocular pressure-lowering eye drops may be used, with oral or intravenous pressure-lowering medications combined as necessary. For cases involving pupil block, laser iridotomy or peripheral iridectomy should be considered promptly under active anti-inflammatory treatment. If extensive synechiae of the angle are present, appropriate glaucoma surgery may be performed.
Complicated Cataract
Cataract surgery using phacoemulsification and intraocular lens implantation is performed once inflammation is well-controlled. Before and after surgery, local or systemic glucocorticoids may be used, and, if necessary, combined with other immunosuppressive therapies to prevent the recurrence of postoperative uveitis.