Minimally Invasive Micro-Sclerostomy (Mims) – Early Results Of A Multicentered Prospective Study

Glaucoma surgery has benefited from the development of several new less invasive techniques (less invasive glaucoma surgery, LIGS, and microinvasive glaucoma surgery, MIGS). The minimally invasive micro-sclerostomy (MIMS) is a less invasive glaucoma filtering surgery. We built an independent prospective multicentered study to evaluate the safety and effectiveness of this technique.

Our study occurred in three Ophthalmology services in private and public hospitals in France, with surgeries being performed by three glaucoma expert surgeons. The MIMS is a filtering surgery, that creates a sclerocorneal canal to lower intraocular pressure using a micro-trephine of 240 µm, activated by a pedal. This surgery lasts 3 to 5 minutes and can be combined with cataract surgery. 

We performed a multicentered prospective interventional study, with National Ethics approval. Inclusion criteria: 1) adult patients who signed informed consent; 2) primary open-angle glaucoma, pseudoexfoliative glaucoma, or pigmentary glaucoma with an indication for glaucoma surgery (defined as uncontrolled intraocular pressure (IOP) or worsening visual fields despite maximum tolerated medical therapy); chronic angle-closure glaucoma patients were included in combined MIMS-cataract; 3) healthy and mobile conjunctiva. We excluded severe systemic and other ocular pathologies. Our main outcome was complete surgical success (IOP decrease of ≥20% without medication, without vision loss nor major complications, nor secondary glaucoma surgery).

We included 25 patients in the three centers, that were followed-up for one year. There were no surgical intraoperative nor postoperative severe complications. There was one failure (a patient who needed secondary glaucoma surgery). There was no clinical hypotony. There were no severe intra-operative complications and the MIMS technique was fast and with a short learning curve. Endothelial cell count decreased significantly in one patient after 3 months, but stabilized at 6 months and the VA remained 10/10. The conjunctival bleb was flatter during time, but the IOP remained controlled. Many patients needed subconjunctival 5FU injections, and several patients needed eyedrops to maintain a qualified surgical success. 

MIMS was a fast and easy filtering surgery, with no severe complications and with good  success rates; but needs attentive follow-up and frequent 5 FU injections. The visual recovery was rapid. Future studies are needed, namely with bigger sample size, longer follow-up, and different populations.