Steroid injections for inflammatory eye problems
Steroid medications (cortisone derivatives) can be injected locally into or around the eye for the management of uveitis and scleritis. These are, generally speaking, very effective treatment options which usually provide control of the inflammatory problem over a period of weeks to several months, depending on the eye, the substance used and the location of the injection. Injections to the eye area obviously create anxiety and fear in patients who have not had them before. However, they are usually painless and sometimes cause very mild and brief pain at the time of the injection. Patients who need to have injections more than once are usually quite relaxed about it after they have had it done once.
The main side effects/risks of locally injected steroids are high pressure in the eye (glaucoma) and cataract formation. These risk increase with increasing number of injections and cumulative dosage.
Specific types of injections are:
1. Injections around the eye (into the orbit): Using the "orbital floor" injection technique (under and/or behind the eyeball): This technique involves injecting a small volume of long acting steroid (triamcinolone, Kenacort) to the tissue just outside the eyeball, usually inserting the needle through the space between the eyelid and the eyeball, . The injection is usually given with some local anaesthetic preparation. It may be followed by minimal swelling and discomfort for a few hours. Sometimes double vision may occur for hours to several days. It is fairly effective for the treatment of inflammation in the vitreous (the "gel") and the back part of the eye (the retina and choroid). It is commonly used for treatment of macular swelling (macular oedema). Typically, it has a favourable effect within a week or two. Sometimes more than one injection needs to be given, before an effect is seen. Patients with chronic uveitis sometimes receive multiple injections over the course of their disease. Others needs the odd injection here and there.
2. Injections into the eye: Using the intra-vitreal technique, a tiny amount of steroid is injected through the eye wall into the centre of the eyeball. The material is deposited in the vitreous, which is the clear gel inside the eye. These injections have to be done under sterile conditions, to reduce the risk of an infection entering the eye at the time of injection. They usually cause immediate floaters (dark shadows moving in the patient's visual field) lasting a few days. This method is very effective in reducing inflammation and swelling, as well as in improving the patient's vision. However the risk of infection, cataract and glaucoma is higher than that of the orbital (external) injections. They are sometimes used if the orbital method has been tried and found not to be effective enough.
This technique of injection is widely used in the treatment of macular degeneration, diabetic retinopathy and other diseases of the blood vessels of the retina. In those conditions, other medications are injected, usually drugs from the "anti VEGF" group. Steroids can also be used in those conditions in some cases.
3. Injections under the surface of the eye (the conjunctiva) : These injections are done for anterior uveitis or scleritis. They may leave a visible deposit of the drug under the surface of the eye for a few months. They are usually very effective for immediate control of scleritis, stopping the pain and redness within hours to days.