Koch F H, Gümbel H O, Hattenbach L O, Ohrloff C
Netzhaut- und Glaskörperchirurgie, Johann Wolfgang Goethe Universität, Frankfurt am Main.
Klin Monbl Augenheilkd. 1999 Feb;214(2):107-11. doi: 10.1055/s-2008-1034759.
The recent development of 20- and 19-gauge diameter endoscopes allows an excellent direct intravitreal visualization of intraocular morphology. A gradient index (GRIN) endoscope (Insight Instruments, Lake Mary, FL, USA), which combines a small diameter (0.89 mm, 20 gauge) and an exceptional optical resolution, can be used as a diagnostic tool for the assessment of the safety and vitreous interaction of sustained release intraocular devices which have been designed to deliver ganciclovir (Vitrasert) over a period of 8-12 months and were successively implanted in several eyes.
78 eyes of 49 patients received 100 ganciclovir implants between November 1995 and July 1998. In six patients who received additional implants, the GRIN endoscope was used as an optical control of wound healing processes and Vitrasert positioning after implantation of prior devices (two-point suturing technique).
In all of these six eyes, a clinical stabilization of the cytomegalovirus retinitis was noted. Endoscopic observation of the scleral 5-mm incision revealed no gaps after two-point suturing of the device. Only one of six eyes showed significant vitreous tractions around the Vitrasert. However, the struts of all pellets were completely covered by a fibrous membrane. Occasional fibrous plaques were noted on the surface of devices which presumably had been damaged by surgical manipulations. In one case, the endoscopic examination disclosed the suprachoroidal implantation of a device. In this eye, no signs of retinal toxicity or recurrence of CMV retinitis were observed.
High resolution endoscopy of the vitreous cavity appears to be an effective method for the control of intraocular drug delivery devices. Basically, 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 struts suggest that the explanation of an intraocular device has the potential for various intraoperative complications (e.g. hemorrhages, traction, tears, retinal detachment). Therefore, we would recommend the additional implantation of further implants rather than a replacement.
20号和19号直径的内窥镜的最新发展使得能够对眼内形态进行出色的直接玻璃体可视化。一种梯度折射率（GRIN）内窥镜（美国佛罗里达州玛丽湖的Insight Instruments公司），其结合了小直径（0.89毫米，20号）和卓越的光学分辨率，可作为一种诊断工具，用于评估设计用于在8至12个月期间递送更昔洛韦（Vitrasert）并已相继植入多只眼中的缓释眼内装置的安全性和玻璃体相互作用。
在1995年11月至1998年7月期间，49例患者的78只眼接受了100个更昔洛韦植入物。在6例接受额外植入物的患者中，GRIN内窥镜被用作在先前装置植入后（两点缝合技术）对伤口愈合过程和Vitrasert定位的光学控制。
在所有这6只眼中，均注意到巨细胞病毒性视网膜炎的临床稳定。内窥镜观察巩膜5毫米切口发现装置两点缝合后无间隙。6只眼中只有1只在Vitrasert周围显示出明显的玻璃体牵引。然而，所有微丸的支柱完全被纤维膜覆盖。在可能因手术操作而受损的装置表面发现了偶尔的纤维斑块。在1例中，内窥镜检查发现装置脉络膜上植入。在这只眼中，未观察到视网膜毒性或CMV视网膜炎复发的迹象。
玻璃体腔的高分辨率内窥镜检查似乎是控制眼内给药装置的有效方法。基本上，眼内更昔洛韦植入物的重复植入可被认为是治疗复发性CMV视网膜炎的一种安全方法。然而，内窥镜观察到覆盖支柱的纤维膜表明，眼内装置的放置有可能引发各种术中并发症（如出血、牵引、撕裂、视网膜脱离）。因此，我们建议额外植入更多植入物而非进行更换。
