New inserts will not reverse the symptoms of glaucoma

06 May 16

written by:

Ade Deane-Pratt

(more articles)

But the good news is that they may be better at preventing future sight loss than existing glaucoma treatments.

There’s a very misleading headline in the national press today about a new treatment for glaucoma. This is a real shame because there is much to be excited about in the results of the research study. But the headline itself could give some people false hope. So let’s take a look at what glaucoma is and what the study actually shows.

What is glaucoma?

Glaucoma is a group of conditions that cause irreversible sight loss due to damage to the optic nerve. This is the specialised cable that sends signals from the eye to the visual parts of the brain.

Several things can increase the risk of getting glaucoma, especially older age, being black or Asian, and having high pressure in the eye. The eye normally holds its shape and stays at a healthy pressure by making a fluid (called aqueous humour) that drains away in equal amounts as more is made.

But if the drainage system becomes blocked, pressure in the eye can rise. If so, it can squeeze and damage the optic nerve, causing sight loss.

Not everyone with high eye pressure has glaucoma (i.e. a damaged optic nerve) and not everyone with glaucoma has high eye pressure. But the main way to treat glaucoma at the moment is to try to lower eye pressure.

Lowering eye pressure can stop more sight loss from happening in the most common form of the condition (primary open angle glaucoma). What it can’t do is fix the optic nerve and bring back sight that has already been lost.

Fight for Sight and other researchers are working hard to find out whether it’s possible to repair the optic nerve. But we’re not there yet and it’s important to be clear about it so people know what they can expect from treatment.

Inserts lower eye pressure

Back to the study then and what it does actually show. The results published in the journal Ophthalmology show that delivering the glaucoma drug bimatoprost by long-term insert is better at lowering eye pressure in people with glaucoma or high eye pressure (ocular hypertension) than treatment with eye drops that are meant to be used twice a day.

A series of 5 images, first showing the silicon insert ring and then eyes at various stages of ring insertion.
The inserts were fitted first under the upper eyelid, then the lower and were almost completely hidden once on. Image copyright © 2016 American Academy of Ophthalmology.

The research team divided 130 adult participants into two groups. One group had a soft, thin silicon rings containing bimatoprost fitted by an ophthalmologist. There was no surgery, the inserts just sit on the outside of the eye hidden underneath the upper and lower eyelids. They gradually release the drug over a period of 6 months. This group also used eye drops containing artificial tears (but no active drug) twice a day.

The second group of participants also had silicon rings fitted, but these didn’t contain any medication at all. Instead, this group was asked to use eye drops containing the glaucoma drug timolol twice a day.

Better than drops

Eye pressure was measured for each participant at the start and at several time points during the 6-month study. After 6 months, eye pressure was 20% lower in participants who’d had the bimpatoprost insert compared to the other group.

This is great news because a key reason that people being treated for glaucoma can go on to have more sight loss is because the daily eye drops routine is difficult for many. People may have trouble putting the drops in correctly due to arthritis or may have problems with memory.

So there is a need for non-surgical treatment that will deliver glaucoma drugs reliably over long periods of time. And finding ways to improve ‘patience compliance’ with their treatment was identified as a top priority for research in the Sight Loss And Vision Priority Setting Partnership.

The aim of this Phase II study was to find out whether the inserts are safe and can do the job without too many side-effects. The results showed that they are effective at lowering eye pressure. And while some participants did need to have their inserts refitted during the study and some had a bit of discomfort, most participants managed well and kept the inserts through to the end of the study. The team is now planning a Phase III study, which is the last stage of research needed before a drug can be approved.

Inserts don’t reverse symptoms

So the inserts won’t reverse the symptoms of glaucoma or restore lost vision. They weren’t designed to do that as we don’t know how yet.

We now have proof of the concept that the inserts can lower eye pressure. But there’s still a lot to understand. Take a look at some of the projects in our strong glaucoma research programme.

What happens to the connections between optic nerve cells in glaucoma?

1 August 15 - 30 April 18

Using precision imaging technology to open up a new line of research.

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Could increasing the pores in the eye’s drainage system be a potential treatment for glaucoma?

1 October 12 - 30 September 15

Targeting the root cause of the main risk factor for glaucoma

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More glaucoma research.