Intraocular Injections and Eye Pain

by Dan Roberts
November 2006
Some people have been reporting considerable pain and/or conjunctival hemorrhaging (eye redness) following intraocular injections of anti-angiogenic drugs (Macugen, Lucentis and off-label Avastin) for wet AMD. Most patients, however, are reporting nothing more than some discomfort. The following information has been gathered from patients who have undergone the procedure.
In preparation for the injection, an anesthetic (to desensitize) and a broad spectrum microbicide (to sterilize) are applied at the injection site. A sterile eyelid speculum (or similar instrument) is used to hold the eyelid open. The injection is administered into the back and side of the eyeball by a syringe. Patients sometimes report a sting when the needle enters, but most report only a feeling of pressure. The injection can leave a small bump that irritates the eyelid for a couple of days. The needle will likely pierce one of the many small blood vessels in the outer covering of the eye. The resulting redness is not painful, nor is it harmful, and it should clear in a day or so.
The pain that is of most concern occurs after the injection. It is a burning sensation that can persist for up to a day afterward, and it is usually accompanied by watering of the eye and foggy vision. This has been reported to be caused by one of three conditions:
1. Allergic reaction to the microbicide solution
2. Corneal abrasion
3. Dry spots on the cornea
If you experience such pain, it would be wise to see an allergist and/or corneal specialist to determine the cause. It is possible that something can be done to alleviate your symptoms, which is much preferred to foregoing treatment and risking further loss of sight from uncontrolled neovascularization.
Soon, researchers will have developed better methods of delivering drugs to the retina. Promising methods include topical eye drops, slow release compounds and encapsulated cell technology. Until then, intravitreal injection has proven to be the safest and most effective procedure, in spite of complications that can arise. Hopefully, administering physicians will continue to search for solutions to such complications for the maximum well-being of their patients.
Principal source: Genentech

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