What is Glaucoma?
Glaucoma is a disease of the optic nerve and is the most common cause of blindness worldwide. Often referred to as ’the thief of sight’, it is a loss of vision which tends to occur so gradually, the patient is usually unaware they’re affected until substantial vision has been lost.
Although vision already lost from glaucoma cannot be restored, there are effective treatments to preserve remaining vision.
Most people with glaucoma are diagnosed after having an abnormality noted by their optician. If your optician suspects glaucoma, ask for referral to a glaucoma consultant or contact Edinburgh Eye Surgeons directly.
What causes Glaucoma?
Glaucoma is normally due to raised pressure within the eye (intraocular pressure) due to an imbalance between the production and drainage of fluid. The increased pressure in the eye puts strain on the optic nerve, which may result in loss of vision.
There are two main types of glaucoma:
Primary open angle glaucoma (POAG)
Primary angle closure glaucoma (PACG)
1 Primary open angle glaucoma (POAG)
POAG is the most common type of glaucoma. In Scotland, POAG affects 2% of of people over age of 40 and 10% of those over the age of 75. POAG is more common with increasing age, in those with a family history of glaucoma, short sight (myopia), diabetes or poor circulation. POAG may also be a side effect of medications such as steroids.
Unfortunately, many people with POAG are unaware they are affected until they have vision problems.
2 Primary angle closure glaucoma (PACG)
In Scotland, PACG is less common than POAG, affecting about 2 in 1000 people aged over 40 years, and it tends to occur in people who are long-sighted (hypermetropia). Interestingly, PACG is much more common in China and in people of East Asian origin.
Although rarer, PACG is a more aggressive form of glaucoma than POAG, with a higher risk of blindness.
Some people with PACG experience a suddenly painful red eye due to very high intraocular pressure but most have no symptoms until irreversible visual loss has occurred.
Tests for glaucoma include:
Measurement of intraocular pressure
Measurement of corneal thickness
Examination of the eye’s drainage channels (gonioscopy)
Examination of the optic disc
Measurement of the optic nerve (optical coherence tomography or OCT).
Traditionally, glaucoma is treated with eye drops. These are effective for many people but treatment is life-long and may have side effects, including red eye and irritation.
There are an increasing number of treatment options for patients with glaucoma, including new laser and minimally invasive procedures. These, combined with more traditional medical and surgical treatments, offer greater potential to preserve vision and reduce the impact of glaucoma on day-to-day life.
Edinburgh Eye Surgeons offer a range of the latest alternative treatments – please contact Edinburgh Eye Surgeons for more information about the following glaucoma treatments.
1 Laser Treatment
Selective Laser Trabeculoplasty (SLT) is a safe, painless treatment for lowering intraocular pressure. It is particularly effective in early glaucoma and can be used as an alternative to eye drops.
2 Minimally invasive glaucoma surgery (MIGS)
Minimally invasive glaucoma surgery is a term used to describe a variety of procedures increasingly used as an alternative to eye drops or traditional glaucoma surgery.
Two MIGS procedures offered by Edinburgh Eye Surgeons include the iStent and the Xen gel stent.
iStent is a small titanium implant which is used, in combination with cataract surgery, to reduce intraocular pressure.
The iStent is inserted into the drainage channel of the eye to bypass blocked channels and lower pressure. This procedure can reduce the need for eye drops and help preserve vision and, due to its excellent safety profile, can be used at a much earlier stage than traditional glaucoma surgery.
Xen gel stent
Dr Tatham of Edinburgh Eye Surgeons was the first surgeon in Scotland to perform this new keyhole procedure.
The Xen is a small collagen tube, which is placed through the wall of the eye (sclera) to create a route so excess fluid can drain into a reservoir under the conjunctiva. It can be used as an alternative to trabeculectomy in some patients.
Advantages are improved safety, quicker procedure time and a quicker post-operative recovery period.
3 Cataract surgery
Cataract surgery can be an excellent treatment for patients with glaucoma, particularly in those with primary angle closure glaucoma (pacg) or combined with a MIGS procedure.
Although cataract surgery can improve vision and lower intraocular pressure, it does carry a slightly higher risk in those with glaucoma. Your Edinburgh Eye Surgeons’ specialist consultant will be able to discuss your options with you.
Trabeculectomy remains the ‘gold-standard’ procedure for most patients with glaucoma who require surgery.
This procedure involves creating a small drainage pathway for excess fluid to drain through the wall of the eye (sclera) into a reservoir under the upper eyelid. The procedure, which takes about 45 minutes, is usually performed under local anesthesia.
5 Glaucoma Drainage Devices
Devices such as the Ahmed Valve or Baerveldt tube and larger drainage tubes can be fitted but these are usually reserved for people with complex types of glaucoma.
Treatment of Primary Angle Closure Glaucoma
Primary angle closure glaucoma (PACG) has a different treatment approach to primary open angle glaucoma (POAG).
As angle closure usually occurs due to contact between the iris and lens obstructing flow of fluid in the eye, laser treatment (peripheral iridotomy) can be used to bypass the obstruction or cataract surgery performed to create more space in the eye.
Further resources (links)
International Glaucoma Association – A UK patient support group which holds regular meetings in Edinburgh.
www.drtatham.com – Dr Tatham’s website has information about a variety of treatments, including SLT, trabeculotomy, iStent and Xen.