Anterior-Segment Optical Coherence Tomography Imaging Of Patients Undergoing Supraciliary Glaucoma Drainage Device Implantation

To evaluate anatomical changes after implantation of a novel supraciliary minimally invasive glaucoma drainage device using swept-source anterior segment optical coherence tomography (AS-OCT).

The prospective study was conducted at the SwissVisio Swiss Glaucoma Research clinic. We included 48 eyes with a diagnosis of open angle glaucoma who underwent MINIject (MJ) implantation (iStar Medical, Wavre, Belgium) as a standalone or combined procedure with cataract surgery were included.

Eyes were imaged postoperatively at 1 day, 1 week, 1 month, 3 months, and 6 months by AS-OCT (ANTERION, Heidelberg Engineering, Germany). Implant depth(ID) was graded from 1(anterior to Schwalbe’s line (SL)) to 3(deeper than SL) and implant position (IP) from 1(close to the iris) to 3(close to the cornea). Cleft width(CW) was graded from 1(minimal hyporeflective (HF) density around the MJ) to 4(HF>4 MJ width) and extent of posterior suprachoroidal fluid (SCF) was graded from 0(no to minimal HF band behind the MJ) to 4(HF band higher than height of the MJ), as well as the mean number of quadrants with SCF. The correlation between the recorded parameters and IOP was analyzed.

Mean SCF grade was 3.07±1.04 on day1 and 1.53±1.12 at 6 months(p<0.001), mean CW was 7.00±1.67 on day 1 and 3.23±0.64 (p <0.001) at 6 months. On average, 3.71±0.77 quadrants displayed SCF at day1 versus 2.21±1.61 at 6 months (P<0.001). Also, 45.5% were located anterior to SL, 33.3% were at the level of SL, and 21.2% were behind SL. We recorded 13.0% of implants close to the iris, 17.4% directed toward the cornea. Depth and position did not change during the 6-month follow-up. There was a significant correlation between IOP reduction and mean SCF drainage(-2.93; P=0.001) and the number of quadrants with visible SCF(-2.51; p=0.002) at 1 month. A deeply positioned implant was associated with better IOP reduction at 3 months -4.35; p=0.004).

To our knowledge this is the first study evaluating anatomical changed after MINIject implantation with AS-OCT. The study demonstrated that the implant remains stable in depth and orientation 6 months post-operatively. Furthermore, the cleft width remained stable and was not associated with IOP lowering at any time-point and is unlikely to be the main cause of post-operative hypotony. SCF drainage and spread appeared to decrease over time and was significantly associated with lower IOP at 1 month, which hints to a state of newfound equilibrium.

AS-OCT is a useful non-contact imaging device for the assessment and follow-up of patients undergoing MINIject implantation.