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January 09, 2019

Seeing Glaucoma

Seeing Glaucoma

Image courtesy of Glaukos

It is estimated that half a million people in the U.K have glaucoma. Glaukos tell us the facts.

What is glaucoma?

Glaucoma is a progressive eye disease that damages the optic nerve and can cause vision impairment and lead to blindness. Glaucoma is asymptomatic, which means it occurs without any symptoms appearing. Without regular eye tests, glaucoma can often go undiagnosed and worsen over time.

What are the different types of glaucoma?

There are two main types of glaucoma:

Chronic or Open-angle glaucoma—this accounts for about 70-90 percent of all cases. Open-angle glaucoma has no symptoms and can often go undiagnosed without regular eye tests, and worsen over time.

Acute or Angle-closure glaucoma—this is less common but more severe, and is marked by pain and potentially rapid and severe vision loss if not managed in a timely manner.

Who is at risk of developing glaucoma?

Glaucoma is believed to be hereditary and may not appear until later in life. It can occur at any age, but is more common in those over the age of 40.

Risk factors can include:

  • Increased eye pressure
  • Having a relative with glaucoma
  • Race
  • Older age
  • Severe short sightedness
  • Poor blood circulation
  • Eye injury
  • Inflammatory eye conditions

What are the symptoms associated with glaucoma?

There are often no obvious symptoms until significant damage has been done to the eye. It can develop over many years and initially affects the edges of the vision.

A regular eye test is the best way to check for glaucoma. The first sign is often loss of peripheral or side vision.Both eyes are usually affected, although it may be worse in one eye.

How does pressure inside the eye affect vision and glaucoma?

A major risk factor for glaucoma is increased eye pressure that occurs when the fluid in the eye, which is used to transport important nutrients to the lens, cannot drain away naturally.

Over time the pressure in the eye increases, which can damage the optic nerve and cause visual impairment.

What happens during a glaucoma eye exam and when are they required?

Free annual eye tests are available on the NHS for those over 60, or over 40 who have a family history of glaucoma. Eye care professionals recommend that everyone over 40 should have an eye check every two years.

During a standard eye test, an optometrist will carry out a series of examinations that check for the signs of glaucoma:

  • An eye pressure test—where the pressure inside the eye (intraocular pressure) is measured.  Raised eye pressure can indicate glaucoma.
  • A visual field test—where a series of light spots are shown.  Some of the spots will appear in the peripheral vision and if they are unable to be seen, it can indicate that glaucoma has caused vision damage.
  • Optic nerve assessment—a retinal camera photograph is taken of the optic nerve and any damage assessed.

What are the different treatments for glaucoma?

Although glaucoma is not curable, early intervention could delay or stop the progression of the disease. Treatment is focused on lowering eye pressure and typically begins with eye drops. However, eye drops could cause uncomfortable reactions in some people like redness, soreness and dryness. This is where new treatments such as Trabecular Bypass Surgery may be able to help.

How does Trabecular Bypass Surgery work to treat glaucoma?

Trabecular Bypass Surgery devices, like iStent inject® are designed to restore the eye’s natural ability to drain fluid in the eye, thus reducing the pressure in the eye[1].  

The iStent inject® is the smallest medical device known to be implanted in the human body[2]. It measures just 0.36mm in length.

How safe and effective are minimally invasive implant treatments?

The procedure is performed by ophthalmologists typically under local anaesthetic. The devices can be implanted at the same time as cataract surgery, or during a separate surgery. More than 400,000 iStent inject® and iStent® implants have been implanted around the world to date[3].

Studies suggest that the iStent inject® procedure is safe and effective[4].An international study has shown 72 percent of patients who were treated with iStent inject® no longer need to take glaucoma medication after 12 months.[5]

What can a patient expect to experience after glaucoma treatment?

Immediately after the procedure the vision in the operated eye might be blurry for one or two weeks, and the eye might be slightly bloodshot for a few days.  The ophthalmologist may prescribe antibiotic and anti-inflammatory eye drops to prevent infection and inflammation.  The ophthalmologist will let the patient know when they can stop taking glaucoma eye drops.

The stents are designed to reduce the pressure in the eye, as the fluid will be able to drain away naturally, potentially reducing or eliminating the need for glaucoma medication (at the discretion of the ophthalmologist) and keeping the pressure in the eye at a safe level.

Mr Imran Masood. Consultant Ophthalmic Surgeon

Glaukos, manufacturers of iStent® and iStent Inject®.

Glaukos and iStent inject are registered trademarks of Glaukos Corporation.


[1] Voskanyan L, Garcia-Feijoo J, Belda J, Fea A, Junemann A, Baudouin C. Prospective, unmasked evaluation of the iStent inject® system for open-angle glaucoma: Synergy trial.  Adv Ther. 2014;31:189-201.

[2] Data on file

[3] Data on file

[4] Neuhann TH.  Trabecular micro-bypass stent implantation during small-incision cataract surgery for open angle glaucoma or ocular hypertension: Long-term results. J.Cataract Refract Surg. 2015; 41: 2664-2671

[5] Voskanyan L, Garcia-Felijoo J, Belda J, Fea A, Junemann A, Baudouin C.  Prospective, unmasked evaluation of the iStent inject® system for open-angle glaucoma: Synergy trial.  Adv Ther. 2014;31:189-201