iStent devices are very small trabecular micro-bypass stents implanted in the eye during minimally invasive glaucoma surgery (MIGS), usually at the time of cataract surgery. The device is placed within the trabecular meshwork to improve the outflow of aqueous humour from the anterior chamber, helping to reduce intraocular pressure in patients with glaucoma. The implants are extremely small and remain permanently within the eye.
According to the manufacturer, several iStent models are MR Conditional and may be scanned safely on MRI systems up to 3 T and up to in First Level Controlled Operating Mode. Models listed as MR Conditional include iStent® (GTS100L / GTS100R), iStent inject® (G2-M-IS), and iStent inject® W (G2-W). Further MRI safety information is available from the manufacturer: https://www.glaukos.com/en-uk/mri-information-uk/.
Within the NHS, the glaucoma stent models we have most commonly encountered are those listed above. However, other ophthalmic implants may exist. If the patient reports having an eye stent that is not one of the models listed, or if the implant cannot be clearly identified, please contact the MRI department for further investigation before scanning.
Example of iStent inject® W below.
