There are three main types of glaucoma treatment, which we’ll briefly discuss here.
Medical glaucoma treatments
Usually, eye drops to lower your intraocular pressure. There are an extensive range of eye drops to achieve this and are mostly the first choice to treat glaucoma. There are two modes of action:
- Eye drops that reduce intraocular pressure by decreasing the fluid production (called the aqueous humour) in the eye.
- Eye drops that reduce intraocular pressure by helping increase the exit of the fluid from the eye.
Mostly, one medication will be all that is required to achieve a significant intraocular pressure reduction. However, in some patients, a combination of drugs will be needed to achieve this, and a lot of the current choices consist of medications combined in 1 bottle. This approach is a good option when indicated since combining medications improves adherence to taking the medication and reduces side effects.
Regarding adherence and side effects, the vast majority of patients will learn to instil their eye drops easily and do not experience significant side effects. All eye drops will sting transiently. Also, we will provide you with information explaining the correct technique to instil eye drops. Once we initiate medical treatment, it is important to continue with regular follow up to measure that the intraocular pressure reduction has been maintained and is consistent. Your clinician will advise you on the recommended monitoring interval which we determine based on the type and severity of glaucoma that you have and whether it is stable or not.
Laser glaucoma treatments
There are two primary types of glaucoma laser treatments:
Laser Peripheral Iridotomy
This treatment is chosen to treat Angle Closure Glaucoma or those patients predisposed to this type of glaucoma. It involves a laser beam creating a small hole in the outer part of the iris (the coloured part of the eye).
In Angle Closure Glaucoma, the access (called the ‘angle’) for fluid to escape the eye has become blocked (angle closure) leading to high pressure in the eye. A sustained rise in pressure can cause permanent loss of sight and central vision. The iridotomy allows fluid to circulate more freely within the eye, minimising the risk of a sight-threatening pressure rise. We can perform this treatment in the outpatient setting as a day case procedure. The vast majority (80-90%) of patients will have their angle closure resolved after this treatment.
Selective Laser Trabeculoplasty
This treatment can be chosen to treat Open Angle Glaucoma or those patients predisposed to this type of glaucoma. Also if you are suffering from side effects associated with glaucoma eye drops, then this option can often enable the clinician to stop or reduce your medication. This approach is also a good first choice if the patient does not want to use eye drops.
This laser treatment works by opening up the drainage channels that control the outflow of the eye fluid and thus to allow more fluid to drain out. It seems to work by stimulating the cells in the trabecular meshwork drainage system to change and drain fluid more effectively. We can perform this treatment in the outpatient setting as a day case procedure.
An SLT can reduce the eye pressure by 25-30% and successfully controls eye pressure in about 70% of eyes one year after the laser treatment. However, its effect may fade with time, and therefore it may need to be repeated.
Surgical glaucoma treatments
There is a range of surgical treatments which are recommended depending on the type of and severity of glaucoma that the patient has.
In older age, the commonest reason to undergo this operation is to improve vision after vision has become blurred due to opacification of the lens inside the eye. However, this procedure can also be used to augment lowering intraocular pressure in Open Angle Glaucoma patients. And it is sometimes the treatment of choice for Angle Closure Glaucoma patients.
In patients with ocular hypertension (a risk factor for Open Angle Glaucoma), one large randomised controlled study found that there was about a 4 mmHg reduction in intraocular pressure after cataract surgery.
In Angle Closure Glaucoma, the access (called the ‘angle’) for fluid to escape the eye has become blocked (angle closure) leading to high pressure in the eye. A sustained rise in pressure can cause permanent loss of sight and central vision. Thickening of the ageing lens can encroach on the drainage angle of the eye narrowing it. Identifying this situation, removing the cataract and replacing it with a thinner artificial lens means that we can potentially resolve this risk factor.
Microinvasive Glaucoma Surgery
Micro invasive glaucoma surgery (MIGS) has become an increasingly important treatment option for some glaucoma patients for the past 5 to 10 years. This type of surgery aims to reduce intraocular pressure; in a less surgically traumatic way followed by less intense postoperative aftercare and more rapid rehabilitation compared to the well-established glaucoma operations such as trabeculectomy and tube surgery. Intraocular pressure reduction is the only proven treatment strategy to slow down and stop deterioration in glaucoma; therefore it is significantly advantageous to your clinician to have as wide a range of treatment options to consider.
The balance between aqueous humour production (the clear liquid inside the eye) and its outflow from the eye results in the intraocular pressure within the eye. The iStent (made by Glaukos®) is one of the MIGS options and is a device we implant into Schelm’s canal (part of the outflow or drainage system within the eye). It is designed to bypass the resistance of the trabecular meshwork, which has become abnormally high in some glaucoma patients. The rationale is that if we overcome this resistance, then the outflow of aqueous humour improves and intraocular pressure lowers. To date, more than 250,000 of this device have been implanted in patients worldwide since its initial development in 2002. It is the smallest device that we can implant in the human body. The iStent is made of titanium and is safe as far as other imaging tests are concerned including CTs and MRIs.
We can implant the iStent as a standalone operation, or combine it with a cataract operation. Studies conducted by numerous groups published in peer-reviewed journals have shown that this device is effective, i.e. a reduction of intraocular pressure is achieved in about 60-70% of patients with primary open angle glaucoma. The final intraocular pressure achieved can be somewhere in the mid teens, compared to a baseline intraocular pressure in the mid-20s. Also, there can be a reduction in medication usage by one bottle and 1-2 medications. The effect of this IOP reduction has been shown to last for up to 4 years so far.
The risks associated with implanting an iStent are similar to a cataract operation. A particular risk associated with this sort of device is postoperative bleeding which is less likely to occur during a cataract operation. The amount of bleeding is usually minimal and resolves after a few days. Also, there can be a transient intraocular pressure increase after the operation which might need some additional medication to settle this issue.
Lydia Chang has been performing this surgery since 2012, and to date, she has performed more than 200 of these operations (mostly with cataract surgery).
Lately, she was an invited speaker presenting on the evidence associated with this device at the World Glaucoma Congress in Helsinki in June 2017.
What she finds potentially beneficial about this treatment are as follows:
- Being able to offer some of her glaucoma patients an effective intraocular pressure lowering treatment, while reserving (and not prejudicing) more interventional glaucoma surgery for a later date if indicated.
- Being able to combine this treatment with cataract surgery at the same time.
- Being able to offer the appropriate glaucoma patients an effective surgical option that can (partially or entirely) reduce dependence on glaucoma eye drops.
- Being able to improve the quality of life of some of her glaucoma patients by reducing their glaucoma medications.
If you are interested in this treatment, Lydia Chang would need to assess your glaucoma, first of all, to determine whether this might be the right option for you.
We recommend this kind of glaucoma surgery for the following reasons:
- If you have advanced severe glaucoma
- If we need to lower your intraocular pressure substantially and other treatments have not successfully achieved this
- If you have developed side effects to other treatments
This operation involves the creation of a new channel within the eye by removing a tiny piece of the wall of the eye, allowing the liquid that is causing the excess pressure to escape through a new opening into a reservoir (called a bleb) underneath the surface covering of the eye.