Most of us have a virus called cytomegalovirus (CMV) in our bodies. Usually, the body’s immune system prevents the virus from causing any problems. However, if for some reason, our body’s mechanisms for defense against infections are severely weakened, the CMV can cause serious diseases. This is often seen in AIDS patients.
In these patients, the most common way for CMV to cause damage is by attacking the retina – the light-sensitive part of the eye. Inflammation and bleeding caused by this virus will eventually damage the retina and may result in blindness. This is called CMV retinitis. The good news is that if the patient receives the correct combination of treatments, the chance of getting CMV retinitis is reduced. However, should the patient develop CMV retinitis, medical therapy is available. The many ways of delivering drugs to treat CMV retinitis are summarized below:
• Daily injections via an intravenous infusion
• A small implant in the back of the eye that delivers a drug via a timed-release mechanism
• Oral medication taken several times per day
• Monthly injections into the white part of the eye
The route of administration depends on the product. Injections into the white part of the eye are not as difficult as most people might think. After a local anesthetic has been used (usually just a couple of eye drops), the patient normally feels little, if any, pain or irritation. The procedure is simple and quick, and allows the patient to return to their daily activities with little inconvenience. It avoids many of the whole body side effects that are so often caused when products used to treat CMV retinitis are given by mouth or by direct injection into the blood.
All of the various drugs and their methods of delivery highlighted above have advantages and disadvantages. The patient will need to discuss treatment choices with his/her doctor.