Low IOP with Preserflo MicroShunt

[KayGeeBee]

I had a Preserflo MicroShunt inserted 16 days ago. At the appointment 7 days after the surgery the pressure was 6 and I had slight distortion to my peripheral vision. Atropine was prescribed as it can help with raising pressure but 9 days later I still have the visual distortions, so suspect the pressure is still too low. I'll find out at my appointment next week.

How long does it take for low pressure to resolve after a MicroShunt insertion and how is it treated if it persists? Has anyone on here had successful resolution of low pressure following a MicroShunt?

Thanks.

[Helen_GlaucomaUK Administrator]

Hello. There is no real set time for your eye pressure to increase, but it is worth giving it the time first. Your eye specialist will of course monitor you closely, including having a look at the back of your eye. As long as that is looking healthy, it's a bit of a waiting game. Very frustrating for you but try to be patient.

If needed they can do revision surgery where a stitch can be put into the Preserflo microshunt. Do ask your eye specialist next week if they think something like the above would be necessary or if they would have a different suggestion, should it be needed.

[KayGeeBee in reply to Helen_GlaucomaUK]

The Atropine did the trick. After being on it for about 11 days the visual distortions went away over a couple of days and at the appointment after 14 days use the pressure was 8 (or 9, I failed to pay attention to which pressure was for which eye). The retinal folds have gone. So the Atropine has been stopped. I'm now waiting for the effect to wear off which I understand can take a long time.

In the meantime, however, my other eye, which had a MicroShunt inserted last December, changed focus during the last two weeks, now giving me big problems reading the snellen chart. It seems to have gone "beyond" long-sighted and I now need weak reading glasses (1.5) to be able to focus at infinity and stronger lenses to be able to focus closer. This eye does fluctuate quite a bit since its operation and I've had several different prescriptions since. So I'm hoping this is just a systemic side effect of the Atropine, or some other sympathetic change because of the dilation in the other eye and it will improve as the Atropine wears off in the other eye. Time will tell...

[KayGeeBee in reply to KayGeeBee]

Once the Atropine wore off, which took just over two weeks, the distortions began to return. I have now been diagnosed with hypotony and a large choroidal effusion. Pressure is between 5 and 8 depending upon the machine used. So I'm back on the Atropine again and the Dexamethasone is being tapered in the hope of building up resistance in the bleb to cause a rise in pressure. (I'm in the 9th week post-op).

Threading a suture into the Preserflo tube seems to be future option if the strategy doesn't work. Has anyone here had this done?

There was also mention of possibly inserting a gel(?) into the anterior chamber to increase its depth, and increase the pressure? I presume this wouldn't block the Preserflo?

[Littletreasures]

Hi following cataract and MIGS in one eye 6 weeks ago my vision is still blurry. I’ve been on Atropine for 5 weeks and have been prescribed a further 4 weeks of it. I had gel injected on Friday last week to treat macular folds but I can’t say there’s been any improvement yet. My eye pressure before the gel injection was 3 raising to 7 afterwards. You have to wait an hour after the injection to get pressures retested before you can leave the hospital.

[KayGeeBee in reply to Littletreasures]

Hello Littletreasures. I'm sorry to hear of your vision problems, but thank you for sharing your experiences. My retinal distortions are currently only affecting my peripheral vision so I don't have the macular blurriness that you are experiencing. I hope the gel will work for you soon. They considered using it today when my pressure was 4 but will reconsider it when I see them again next week. Was the gel injected in the clinic or did you have to go back to theatre?

[Littletreasures in reply to KayGeeBee]

It was done in the clinic.

[KayGeeBee]

Just adding an update in case it helps anyone else in the future:

After about five weeks on Atropine after the effusion had returned the second time we decided to try the gel injection. This caused a brief pressure spike which had the immediate effect of pushing out the effusion and restoring the shape of the retina, and the visual distortions went away.

The Atropine was stopped at this time and once it had worn off after about 16 days the effusion began to return for a third time. But the dexamethasone had tapered to zero at about this point and scaring and resistance in the bleb seemed to arrest the progress of the effusion in its early stages and after about a week it started to reverse and has now gone. The pressure was 7.

So, a bit of a rough ride, but hopefully the hypotony issues are now behind me.