Glaucoma
Glaucoma is a group of eye conditions that affect the optic nerve and can cause irreversible vision loss. It tends to cause a gradual loss of peripheral vision which is generally asymptomatic. For this reason, it is often referred to as “the silent thief of sight”. Glaucoma is the second most common cause of blindness worldwide. Given the asymptomatic nature of glaucoma, it is important to have regular comprehensive eye examinations including detailed examination of the optic nerve. In addition to clinically examining the eye and nerve, this often involves an assessment of the thickness of the optic nerve (otherwise known as the peripapillary retinal nerve fibre layer) with ocular coherence tomography (OCT) scans and visual field testing.
Whilst there is no cure for glaucoma, the goal of therapy is to slow the progression of the disease. Current glaucoma treatment involves lowering the intraocular pressure (the pressure inside the eye). There are several ways that this can be achieved – either using topical drops, laser or surgeries. The Ophthalmologists at Rockhampton Eye Clinic are experienced in the assessment and management of glaucoma and will be able to collaborate with you to establish a treatment plan to effectively manage your condition.
Glaucoma may be considered as either ‘open angle’ or ‘closed angle’ glaucoma. The ‘angle’ refers to the anterior chamber angle of the eye which is where the fluid that causes the pressure inside the eye (the aqueous humour) drains. There are several laser treatments that may be recommended for your condition depending on whether you have ‘open angle’ or ‘closed angle’ glaucoma.
Glaucoma Topical Therapy
Topical eye drops remain the most common treatment for glaucoma. There are several different classes of drops available to lower the intraocular pressure. These drops work by either reducing the production of the fluid in the eye (the aqueous humour) or by increasing the flow of that same fluid out of the eye.
Some tips to help ensure your drops work effectively include:
- Regularly taking your drops every day (and at the same time of the day) as instructed
- If you forget to take a dose, apply the missed dose as soon as you remember
- Making sure the drops are instilled in the correct eye
- If using more than one eye drop, making sure you wait three to five minutes between application of the drops
- Ensure you have sufficient drop refills on your prescription (and if you require further prescriptions, please contact the clinic and we can arrange these for you)
Glaucoma Laser Procedures
Selective Laser Trabeculoplasty
Selective laser trabeculoplasty (SLT) is one way in which we can achieve a lower intraocular pressure. It achieves this by increasing the amount of fluid which drains from inside the eye via the anterior chamber angle.
SLT involves the application of short pulses of low energy laser to the pigmented portion of the drainage angle (the structure via which the fluid drains out of the eye). The pigmented cells selectively take up the laser and this leads to ultrastructural and chemical changes which allow more fluid to drain from the eye.
SLT can be used either independently or in conjunction with topical glaucoma medications in people with open angle glaucoma.
Patients with angle closure glaucoma or a history of inflammation in the eye (uveitis) may not be suitable for SLT.
Prior to the SLT treatment a drop of topical anaesthetic is placed on the eye which is receiving the treatment. A special contact lens is then placed on the eye which allows a clear view of the drainage angle.
The procedure itself then only takes a few minutes. You will hear a beeping sound and may see a bright light as the laser is applied. The procedure itself is generally not painful however you may notice a slight tingling sensation with the laser spot application. Generally, we apply between 50-100 spots depending on the extent of treatment.
You will have your eye pressure checked after the procedure and before you go home. We generally do not commence any additional eye drops however do ask that you remain on any glaucoma medications you are currently taking. You may notice that your vision is slightly blurred for a day or so after the procedure and you may experience light sensitivity. The eye may also be gritty (for which topical lubricating drops can be helpful). You may return to normal activities after the procedure.
Generally we recommend an interval pressure check in one to two weeks after the procedure to check the eye pressure. It takes 4 to 6 weeks however for the full effect of the laser at which time we arrange another visit to assess your progress.
Laser Peripheral Iridotomy
Laser peripheral iridotomy is indicated in patients with closed anterior chamber angles. This procedure involves delivering laser energy to create a small hole in the peripheral iris (the coloured part of the eye). This improves the circulation of the fluid inside the front of the eye (the aqueous humour) and prevents it from building up behind the iris which may obstruct the anterior chamber angle and cause an increase in the pressure inside the eye. This process may occur gradually or sometimes suddenly, the latter of which can cause the pressure to suddenly escalate – this is known as an acute angle closure – and can cause significant damage to the optic nerve and loss of vision.
Prior to the laser peripheral iridotomy treatment, a drop of topical anaesthetic is placed on the eye which is receiving the treatment. Another eye drop which works to constrict the pupil (called pilocarpine) is then also applied. A special contact lens is then placed on the eye which allows a clear view of the peripheral iris where the treatment is to be delivered.
The procedure itself then only takes a few minutes. You will hear a beeping sound and may feel the laser as it is applied. A few treatment spots may be required to create an adequate sized iridotomy.
You will have your eye pressure checked after the procedure. We generally advise a short course of topical steroids to assist with the transient inflammation that results from the procedure. You may have a brow ache or headache for a short period after the laser due to the pilocarpine eye drops. You may notice that your eye is sensitive to the light for a few days after the iridotomy. You can return to normal activities after the procedure.
You will be reviewed a few weeks after the procedure to check the intraocular pressure and assess the patency of the iridotomy as well as the appearance of the drainage angle.
Glaucoma Surgeries
Minimally Invasive Glaucoma Surgeries (MIGS)
An important recent development in glaucoma care has been the advent of Minimally Invasive Glaucoma Surgeries (MIGS). MIGS is an umbrella term used to describe a range of surgical glaucoma procedures that have the benefit of lowering the pressure with a faster recovery and generally a more favourable risk profile than the traditional glaucoma surgeries. MIGS procedures available at Rockhampton Eye Clinic include:
- iStent
- Hydrus
- Gonioscopy Assisted Transluminal Trabeculotomy (GATT)
- PRESERFLO MicroShunt
Trabeculectomy
Trabeculectomy is one of the oldest and remains one of the most effective, glaucoma surgeries for lowering the intraocular pressure. Trabeculectomy is indicated when other glaucoma treatments have been exhausted, or are poorly tolerated, and there is progression of the disease.
Trabeculectomy involves making a small opening in the white of the eye (the sclera) underneath a small flap to provide a way for the aqueous fluid to flow out of the eye. The fluid collects underneath the conjunctiva in a reservoir called ‘the bleb’. The scleral flap is carefully stitched closed to modulate the flow of fluid out of the eye. These stitches can be released to modify the flow through the trap door depending on the eye pressure. The bleb is usually hidden and protected by the upper eyelid.
The body’s natural response to surgery is to try and heal the tissue which leads to scarring. This can cause the bleb to fail and the pressure to rise. To try and mitigate this, we commonly use an anti-scarring medication at the time of surgery called Mitomycin C.
The goal of trabeculectomy surgery is to reduce the pressure in the eye and in so doing aims to prevent or slow further damage from glaucoma. Unfortunately it will not restore the vision already lost from glaucoma.
The surgery is performed as a day surgery. It usually takes 45minutes to an hour to perform and is generally done under sedation along with anaesthetic around the eye. During the surgery you may be aware of what is going on around you however there should not be any pain and, if there is, further anaesthetic can be given.
Patients are generally discharged from hospital the same day as the surgery. It is helpful however to have a friend of relative accompany you home after the procedure. The eye will have a pad and shield on it that remains on until your review the next day.
It is normal that your vision is going to be blurred for the first few weeks/month after the surgery. This can take a number of months to stabilise. The eye may also be uncomfortable and gritty immediately after the surgery. The postoperative drops that are prescribed will help with this however, lubricating eye drops can also be used which provide additional relief.
It is important to avoid strenuous activity and bending or heavy lifting after the surgery for the first month. Dr Hogden will advise you regarding return to normal activity depending on you progress and intraocular pressure. You should also keep your eye dry and avoid swimming to minimise the risk of infection.
There will be a number of post-operative visits after the surgery. These are important to determining the functional status of the bleb (where the fluid drains to) and optimise drainage. Depending on the pressure and degree of scarring, stitches may need to be removed or further injections of antimetabolite medication given to help modify the healing process.
Glaucoma Drainage Device
Glaucoma drainage devices are another type of glaucoma filtration surgery (along with the trabeculectomy surgery). These devices provide a conduit for fluid to flow out of the eye and thereby lower the intraocular pressure. A glaucoma drainage device is indicated when topical glaucoma therapies, laser or other surgical techniques have become insufficient to control the intraocular pressure. Glaucoma drainage devices that Dr Hogden commonly uses include: the Baerveldt tube, Paul glaucoma tube and Ahmed tube.
There are several types of Glaucoma Drainage Devices (GDD) available. All of them however consist of a tube (which is a conduit to allow fluid to exit the eye) attached to a drainage plate. The tip of the tube is placed in the eye and the drainage plate is fixed under the outer coverings of the eye to the sclera. The aqueous fluid then drains from the inside of the eye via the GDD tube to the drainage plate thereby creating a filtering area (which is called a bleb). The site at which the tube is inserted into the eye is covered by a patch graft (often using donor sclera) which helps to protect it.
Insertion of a GDD takes place in the operating theatre, usually under sedation with additional anaesthetic placed around the eye. Depending on the type of GDD used (whether it is a valved or non-valved device), the tube may be temporarily obstructed at the time of surgery using a stent or a ligature suture to prevent the pressure of the eye going too low in the immediate period after the surgery. If a stent is placed this may be removed a few months after the surgery.
Patients are generally discharged from hospital the same day as the surgery. It is helpful however to have a friend of relative accompany you home after the procedure. The eye will have a pad and shield on it and this remains on until your review the next day.
It is normal that your vision is going to be blurred for the first few weeks after the surgery. This can take a number of months to stabilise. The eye may also be uncomfortable and gritty immediately after the surgery. The postoperative drops prescribed will help with this however you may also use lubricating eye drops as required.
It is important to avoid strenuous activity and bending or heavy lifting after the surgery for the first month. This is particularly important if your eye pressure is low after the surgery. You should also keep your eye dry and avoid swimming to minimise the risk of infection for the first post-operative month.
There will be a number of post - operative visits after the surgery and Dr Hogden will advise you of these depending on your progress.
This is general information only. Prior to any procedure the Ophthalmologists at Rockhampton Eye Clinic will have a comprehensive discussion with you regarding the specific benefits and risks of the procedure as well as after care needs. If you have concerns after any procedure performed such as reduced vision or eye pain please contact our clinic to arrange review or alternatively visit your nearest Emergency Department.
Better Vision Starts Here
Our mission is to preserve and enhance your vision with expert care, advanced technology and a deep commitment to your quality of life.