Oral ganciclovir therapy is probably adequate therapy for patients with lesions that do not threaten the optic disc or the fovea, the part of the retina most critical for visual acuity, but for patients with central lesions, oral ganciclovir does not provide sufficient protection. The major advantages of oral ganciclovir are a significant reduction in neutropenia and the elimination of the risk of central-line sepsis. Other roles are being explored for oral ganciclovir, particularly as primary prophylaxis and as an element of combination anti-CMV therapy. Intraocular implants do not protect against extraocular CMV infections, but a recent study indicates that coadministration of chronic oral ganciclovir therapy with the implant can substantially reduce the risks that the patient will develop CMV in the contralateral eye or extraocular disease. The implant offers the most efficacy of any initial treatment for CMV retinitis, probably due to the high intravitreal concentrations of drug that it delivers.
Implants contain enough ganciclovir to last about eight months.
However, certain risks do accompany this treatment. The implants need to be placed surgically, and the procedure may contribute to retinal detachment. However, the results of a recent study indicate that coadministration of chronic oral ganciclovir therapy with the implant can substantially reduce the risks that the patient will develop CMV in the contralateral eye or extraocular disease. The contralateral eye is not protected with unilateral implants, and patients who choose this option should be aware that most implant recipients experience a transient decrease in acuity in the implanted eye. Despite these caveats, intraocular implants are an attractive option for some patients, particularly those with central lesions who still have reasonable vision in the affected eye.