Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, 110029, New Delhi, India.
Center for Biomedical Engineering, Indian Institute of Technology Delhi, 110016, New Delhi, India.
Biomed Microdevices. 2022 May 19;24(2):17. doi: 10.1007/s10544-022-00618-y.
The standard of care for posterior segment disorders such as wet age-related macular degeneration, diabetic macular oedema and retinal vascular occlusions is pharmacotherapy by intravitreal drug delivery. Since the therapeutic effect of these drugs lasts only around 4 to 8 weeks, repeated intravitreal injections are required. Pain is experienced by the patients during injection as the needle courses through the sclera and choroid. The current work describes the design and development of a novel anodized titanium alloy implant that allows for intravitreal injections through the implant so that the needle transverses only the conjunctiva, thus minimizing discomfort to the patient. Both ex-vivo testing of the implant in enucleated goat's eye as well as in-vivo validation in rabbit eyes was carried out. The implant was placed through pars plana via a minor surgical procedure and was sutured to the sclera and covered with conjunctiva. Subsequent intravitreal injections were administered under topical anaesthesia with a 30-gauge needle through the implant thus delivering the drug into the vitreous cavity. Repeated intravitreal injections were administered every 2 weeks via the implant for 3 months in 4 rabbits. Apart from cataract in 1 rabbit, no complications were observed. There was no evidence of intra-ocular inflammation or infection at final follow-up. Histopathological analysis did not reveal any inflammation or necrosis around the area of implant. The implants were subsequently removed at 5 months and scleral wound was closed with a single suture. The sclera and overlying conjunctiva healed well and no intraocular complications were observed after removal.
对于后节疾病，如湿性年龄相关性黄斑变性、糖尿病性黄斑水肿和视网膜血管阻塞等，标准治疗方法是通过玻璃体内药物输送进行药物治疗。由于这些药物的治疗效果仅持续约 4 至 8 周，因此需要重复进行玻璃体内注射。由于针头穿过巩膜和脉络膜，患者在注射时会感到疼痛。目前的工作描述了一种新型阳极氧化钛合金植入物的设计和开发，该植入物允许通过植入物进行玻璃体内注射，从而使针头仅穿过结膜，从而最大程度地减少患者的不适。已经对从山羊眼球中取出的植入物进行了离体测试，并且对兔眼进行了体内验证。通过睫状体平坦部的小手术将植入物放置，并通过缝线将其固定在巩膜上，并覆盖结膜。随后在局部麻醉下通过植入物用 30 号针头进行玻璃体内注射，从而将药物输送到玻璃体腔中。在 4 只兔子中，每隔 2 周通过植入物进行重复玻璃体内注射，持续 3 个月。除了 1 只兔子发生白内障外，没有观察到其他并发症。在最终随访时，没有证据表明眼内有炎症或感染。组织病理学分析未显示植入物区域周围有任何炎症或坏死。随后在 5 个月时取出植入物，并通过单个缝线关闭巩膜伤口。巩膜和覆盖的结膜愈合良好，取出后未观察到眼内并发症。
