Primary Open Angle Glaucoma, Angle Closure Glaucoma, Pseudo-Exfoliation glaucoma (PXF), Pigment Dispersion Glaucoma, Inflammation and Steroid Induced Glaucoma, Traumatic Glaucoma, Congenital and Anterior Segment Dygenesis

Other Glaucomas:

Irido-Corneal Endothelium syndrome (ICE), and Aniridia, Epithelial Ingrowth, glaucoma associated with corneal disease or surgery, and glaucoma associated with emulsified silicon oil are all examples of rare diseases that are managed frequently in our group.

This is numerically the most common form of the disease covered by the umbrella term of ‘Glaucoma’. It is usually a disease of people over the age of 60, but certainly can occur before this. Around half of people have a family history of glaucoma with this disease and a number of causative genes have been identified. One of us (Michael Coote) was involved in the discovery of the first gene in glaucoma, GLC1 a, in 1996 when he was working in the USA. This gene causes an early onset disease, often in the 20s 30s and 40s and is strongly inherited.

Classically the eye pressure rises and then there are identifiable changes to the Optic Nerve. Later there is the development of visual field defects (loss of vision in the mid and far-periphery) which are often not noted by the patient. Primary open angle glaucoma usually progresses at a reasonably predictable rate and is amenable to drops, laser, or surgery as required.

Occasionally glaucoma will manifest to the patient with loss of clarity and a noticeable change in vision. All forms of glaucoma visual loss are (essentially) not recoverable – loss of vision is always permanent when caused by glaucoma, so prevention is the key.

There is a discernible version of Primary Open Angle Glaucoma known as Low Tension Glaucoma or Normal Tension Glaucoma (LTG or NTG). In in LTG or NTG the eye pressure does not reach statistically abnormal levels, although it is usually above average (taken as 15 mmHg). This is not to say that eye pressure is not important in the development of visual loss in LTG and NTG, it certainly is, but that the eye pressure does not start off statistically elevated. Although there are genetic and racial predisposition (particularly Japanese) and some demographic risk (thin, tall, athletic postmenopausal women with low blood pressure) NTG and LTG can occur in many different human demographics.

Particular care must be taken in treating the LTG/NTG version of glaucoma as there is a tendency to over treat. Whilst there is no doubt there are progressive forms of glaucoma starting with low pressures, there are a great number of patients who have eyes and tests that look like LTG and NTG but do not benefit from treatment. They may need enduring ‘risk management’ to identify change should it occur, but they may not benefit from any form of intervention or treatment.

Proven progressive LTG/NTG may well need surgical intervention due to the difficulty of lowering pressure with nonsurgical means when the starting pressure is relatively low.

This is a very common cause of glaucoma and in certain populations is more is the most common form. It is a partly inherited condition, but also is associated with getting older and developing cataract (or the precursor of an enlarged lens). Angle closure glaucoma can, uncommonly, present suddenly with pain and loss of vision in the eye. We call this acute angle closure glaucoma and this requires urgent treatment.

Angle closure glaucoma has a deliberately more preventative strategy as the underlying problem is more mechanical. Laser Iridotomy (see under treatment) is usually performed well ahead of any event to reduce the chances of a sudden angle closure event. Cataract surgery becomes an important part in the management of angle closure, more so than any other form of glaucoma.

Angle closure can be treated with drops and other medications, and laser and classical glaucoma surgery is effective.

PXF glaucoma is common and can manifest in the 40s and 50s, but is much more common as we age. Mercifully this is a disease which is usually quite asymmetric, being much worse in one eye than the other. Unfortunately it is a form of glaucoma that can produce significant loss of vision in the affected eye and can be difficult to control. Although the predisposition to PXF has a genetic component, it is less obviously inherited, and the severity of the disease is quite variable.

PXF glaucoma will often need surgery and this will often include cataract surgery if it has not been performed. Glaucoma surgery does have a higher rate of failing in PXF and there is a tendency to adjust surgical strategies to take this into account. We have pioneered new ways to make management of this disease safer, especially in the elderly.

Long-term problems with PX F glaucoma include a dislocation of the intraocular lens, classically described 10 years after the original cataract operation. This does happen only in small minority of patients with PX F, but it is very rare in other people. Dislocation of the intraocular lens can be fixed with surgery – and this is an operation we have extensive experience in.

Pigment Dispersion Glaucoma presents with a wide range of severity, with the worst affected people developing significant glaucoma in their 20s. Pressures can fluctuate quite markedly including to symptomatic level where patients will notice intermittent blurring of vision related to high pressures. This can happen spontaneously or after exercise.

Pigment Dispersion Glaucoma is due to iris pigment flaking off and depositing in the drain plug, the trabecular mesh work, and causing gradual obstruction. By blocking the outflow from the eye the pressure increases and causes damage to the nerve. Pigment Dispersion Glaucoma treatment is more centred around laser than in most other forms of glaucoma. Selective Laser Trabeculoplasty (SLT) is an important form of treatment in many forms of glaucoma, but particularly so in Pigment Dispersion.

There are many different sub-types of inflammation in the eye – each with a different underlying cause and often with different treatments. Inflammation can wax and wane and over many years and many eyes with long term and repeated inflammation can develop problems with pressure. Sometime inflammation will present with high eye pressure, such as the Possner-Schlossman syndrome.

Treatment of uveitis and steroid induced glaucoma is a process very much dependent upon the underlying diagnosis and the speed of progression. This is more complex and nuanced, and depends on a great number of factors individual to the patient.

The management of glaucoma associated with inflammation or steroid use is effective. Broadly the treatment of inflammation needs to take precedence and be satisfactory to control inflammation and stop damage to the eye from it. If the treatment contributes to glaucoma then this is frustrating but it is the correct outcome. Under-treated or untreated inflammation is substantially more damaging to the eye that the treatment or the secondary glaucoma, and the glaucoma can be treated once it’s recognised.

We will usually manage uveitis glaucoma in concert with a uveitis doctor.

Injury to the eye can cause a number of enduring complications but glaucoma is a common one. This most often happens after blunt injury to the eye, such as occurs after a tennis ball or a blow to the eye. In this instance the pressure may rise initially then settle only to rise again later, sometimes much later. After blunt injury a risk management strategy around developing glaucoma needs to be implemented lifelong. This does not need to be too onerous and will often involve optometry.

Traumatic glaucoma often eggs exist in an eye that is otherwise injured and reconstruction of the front part of the eye is often involved in managing the glaucoma. This involves surgery to the cornea or iris and sometimes the replacement of the lens, either artificial or original which may need to be sutured in place.

We will work with retinal doctors and corneal doctors with complex trauma cases to restore and/or preserve vision, and to create a comfortable and cosmetic eye.

Glaucoma can occur in infants and childhood, and sometimes congenital conditions can manifest as glaucoma in early adult hood. These are usually where some part of the front of the eye is mis-formed creating an obstruction to fluid outflow and elevated pressure. If these are in a child or baby we will manage this in concert with a paediatric ophthalmologist, but if the child is older or a young adult that will not be necessary.

These conditions are complex and vary significantly from patient to patient. Good treatments are available but more often will require surgery to control pressure.

At Melbourne Eye Specialists and Melbourne Glaucoma Specialists we treat Glaucoma through:

Medication

Laser

Minimally Invasive Glaucoma Surgery (MIGS)

Trabeculectomy

Revision Trabeculectomy

Non-penetrating Glaucoma Surgery

Deep Sclerectomy

Canaloplasty

Viscocanalostomy

Glaucoma Drainage Devices (GDDs)

Molteno Implants

Baerveldt Implant

Cycle-Diode Laser

Lasers have a large role to play in ophthalmology as the clarity of the front of the eye allows laser light to enter the eye. There are many different types of laser, both in ophthalmology and in glaucoma, so one person’s experience of laser may well be quite different from another.

Laser Peripheral Iridotomy

• Performed for angle closure mechanism, or where the iris maybe occluding/has a risk of occlusion of, the angle. This is angle closure, and laser iridotomy is tremendous at reducing the risk. Laser iridotomy does not change the focus or appearance of the eye and is invisible to the patient. Although it does markedly reduce the risk in patients who have risk of angle closure.

Selective Laser Trabeculoplasty

• Selective Laser Trabeculoplasty (SLT), can be done in our rooms, causes minimal discomfort, and can be very effective in lowering intraocular pressure without drops.

Other lasers include:

• Cyclodiode laser, which is done in a hospital. This reduces the amount of fluid production in the eye and can decrease the intraocular pressure that way; and

• Iridoplasty, which can change the form of the iris, particularly if the iris is becoming entrapped in the angle in spite of peripheral iridotomy.

MIGS is a recent term which covers a variety of new devices: the classic MIGS devices are "trans-trabecular" - in other words the traverse the trabecular meshwork and seek to reinstate aqueous flow into the original canal (of Schlemm). The two available in Australia are the iStent and the Hydrus and they operate in a similar manner.

The XEN implant is more akin to standard filtration operations (such as the trabeculectomy and non-penetrating glaucoma surgery). The implant improves the reliability and speeds the recovery from the procedure and is becoming an attractive alternative to the larger glaucoma operations. (Assoc Prof Coote chairs the advisory committee for XEN through Allergan).

Trabeculectomy remains the mainstay of glaucoma surgery. Trabeculectomy was so named for the removal of the trabecular meshwork, although the major way trabeculectomy works is by filtration of fluid from the inside of the eye into the tissue around the eye. This is all performed underneath the upper lid, and this procedure has evolved markedly over the last 40 years. It is done in a hospital, usually under local anesthetic usually and as a day case. It involves making a small hole in the wall of the eye, which is covered then by a partial thickness flap. Resistance to fluid flow is achieved by releasable stitches, the area is soaked in an anti-inflammatory material and then the tissue closed in a watertight fashion. Trabeculectomy has different variations and some of these are valuable at improving outcome or decreasing complications in particular types of eyes. Trabeculectomy is an imperfect operation, but it is dramatically better than it used to be and it is employed when it is unsafe to allow the eye to continue with medical treatment only for the glaucoma. It is rare for the glaucoma operation to fail early, but it can, and then may well need further intervention by the surgeon.

One of the big advances in glaucoma surgery over the last 20 years has been the increasing success of fixing the problems that arise in glaucoma surgery. In general these will be where the glaucoma operation fails to lower the pressure satisfactorily, where the pressure is too low, or where the operation produced an unintended side effect. All of these issues are resolved by revision of the trabeculectomy, which involves a number of different types of operations, which are performed less commonly but now with much greater success. Revision trabeculectomy is a subspecialty area and can be very successful in quickly resolving problems that develop.

A/Prof Michael Coote has written and talked extensively on revision trabeculectomy and is considered a world expert in this area. Revision trabeculectomy may not be the appropriate solution where a previous operation has failed, but its role and success has expanded markedly and it has offered, for a great number of patients, a simple and effective solution to their problems.

Non-penetrating glaucoma surgery is a newer advance in the history of glaucoma filtration surgery. As the name suggests, it differs from standard trabeculectomy by not completely entering the eye. The intent is to make the eye wall more porous and lower the pressure at a more regulated, gentle way, reduce the postoperative complications as well as the number of postoperative visits.

Non-penetrating glaucoma surgery has come a long way since its first iterations and has now a significant role to play. It is not for everyone and is not likely to completely supplant trabeculectomy. It does, however, have a role to play; it may be better for some patients facing glaucoma surgery. Please ask one of our doctors if you are appropriate for non-penetrating glaucoma surgery.

Deep sclerectomy is a version of non-penetrating glaucoma surgery. In this, the sclera is excised underneath the flap in order to make a porous chamber and allow fluid to exit the eye in a more controlled way. It does offer some advantages as well as some disadvantages and, as usual, the question of whether it is appropriate for you will be answered in consultation with your doctor. Non-penetrating glaucoma surgery and deep sclerostomy are two procedures that are only offered through Melbourne Eye Specialists.

Canaloplasty is an elegant technique, which involves opening of Schlemm’s canal. Schlemm’s canal is the main collecting duct for aqueous; dilating this and allowing higher levels of flow out of the eye without opening directly into the front of the eye offers advantages. Canaloplasty is evolving and it may have a role in certain types of glaucoma.

Melbourne Eye Specialists offers canaloplasty to its patients, but the decision about whether or not it is right for you, needs to made in consultation with a treating ophthalmologist.

Viscocanalostomy is an opening of Schlemm’s canal using a viscous substance, usually Helon, often used ta the time of cataract surgery. Viscous material is injected into Schlemm’s canal to dilate it, but nothing is left in place and is usually combined with deep sclerectomy or non-penetrating glaucoma surgery.

Its role in the treatment of your glaucoma needs to be discussed with your treating ophthalmologist. Melbourne Eye Specialists offers viscocanalostomy in context of deep sclerectomy and non-penetrating glaucoma surgery.

Glaucoma drainage devices is an umbrella term used to describe two main tube and plate devices, which have been available to patients for many years. These two are the Molteno implant and the Baerveldt implant. Both implants are structurally quite similar and involve the insertion of a very fine tube into the front part of the eye, allowing fluid, aqueous, to drain to a plate, which is placed around the outside of the eye but underneath the tissue, up underneath the upper lid.The use of glaucoma drainage devices has, in the past, been restricted to more complicated situations, but the role of these devices is getting revisited and refined as new research emerges.Melbourne Eye Specialists offers both a Molteno and Baerveldt implant for patients, but, as usual, the choice will be in consultation with your ophthalmologist..

Prof Tony Molteno, who designed the Molteno implant, did so whilst living and working in South Africa. Many years ago he emigrated to the south island of New Zealand where these implants are still made. The Molteno implant has gone through a number of revisions and the Molteno 3 implant, the one we now use, is a refined and highly tested device, which is used in a variety of circumstances, often where other forms of glaucoma surgery are less likely to be effective.

George Baerveldt designed this implant in the early 1980s and many of these implants have been used around the world. It is not structurally dissimilar to a Molteno implant and indeed both Baerveldt and Molteno both originate from South Africa where glaucoma in the black community has traditionally been very difficult to manage and no doubt stimulated this work. The Baerveldt implant is implanted in a very similar way to the Molteno implant and the choice between the two, the Molteno and the Baerveldt, is often not a critical one.

Melbourne Eye Specialists offers both Molteno and Baerveldt implants for their patients, and the choice and process will be discussed with your ophthalmologist.

Cyclodiode laser is a method of reducing aqueous production in the eye. It is a laser that is done under a local anaesthetic and relatively high-powered laser is passed across the wall of the eye in order to reduce the production of aqueous. Cyclodiode laser is usually performed where other treatment options have also been employed. It is most often used as an adjunct, but can be used as a primary treatment in uncommon circumstances. Cyclodiode laser is only offered through the Royal Victorian Eye and Ear Hospital, but all three of our glaucoma doctors have appointments at the Eye an Ear Hospital and can perform cyclodiode laser on Melbourne Eye Specialists patients in that facility.