Intravitreal endoscopic visualization of intraocular ganciclovir devices: Improved long-term treatment of CMV retinitis

Background The recent development of 20- and 19-gauge diameter endoscopes a llows an excellent direct intravitreal visualization of intraocular morphol ogy. A gradient index (GRIN) endoscope (Insight Instruments, Lake Mary, FL, USA), which combines a small diameter (0.89 mm, 20 gauge) and an exception al optical resolution, can be used as a diagnostic tool for the assessment of the safety and vitreous interaction of sustained release intraocular dev ices which have been designed to deliver ganciclovir (Vitrasert(R)) over a period of 8-12 months and were successively implanted in several eyes. Patients and Methods 78 eyes of 49 patients received 100 ganciclovir implan ts between November 1995 and July 1998. In six patients who received additi onal implants, the GRIN endoscope was used as an optical control of wound h ealing processes and Vitrasert(R) positioning after implantation of prior d evices (two-point suturing technique). Results In all of these six eyes, a clinical stabilization of the cytomegal ovirus retinitis was noted. Endoscopic observation of the scleral 5-mm inci sion revealed no gaps after two-point suturing of the device. Only one of s ix eyes showed significant vitreous tractions around the Vitrasert(R). Howe ver, the struts of all pellets were completely covered by a fibrous membran e. Occasional fibrous plaques were noted on the surface of devices which pr esumably had been damaged by surgical manipulations. In one case, the endos copic examination disclosed the suprachoroidal implantation of a device. In this eye, no signs of retinal toxicity or recurrence of CMV retinitis were observed. Conclusions High resolution endoscopy of the vitreous cavity appears to be an effective method for the control of intraocular drug delivery devices. B asically, the repeated implantation of intraocular ganciclovir implants can be considered a safe method in the management of relapsing CMV retinitis. However, the endoscopic observation of fibrous membranes covering the strut s suggest that the explantation of an intraocular device has the potential for various intraoperative complications (e.g. hemorrhages, traction, tears , retinal detachment). Therefore, we would recommend the additional implant ation of further implants rather than a replacement.