If normal methods of reducing the intra ocular pressure (IOP) of the eyes of a patient suffering from glaucoma, through the administering of eye drops or by taking medication do not work effectively, then surgery is an option that needs to be considered.
Some patients comment that over a long period of time the cost of eye drops and medication can prove too high and the one-off cost of surgery may be attractive. It all depends on a patient’s physical and mental attitude to surgery.
Should cost dictate a decision to choose surgery over eye drops? Absolutely not! The decision should be based on what is the safest and most effective option. How can you put a cost on the safety of your eyesight?
Surgical techniques on the eye, especially those involving lasers, have largely become routine in today’s day surgeries and hospitals.
Methods involve a variety of ways to do the same thing – open up or relieve some part of the eye to enable drainage of excess aqueous humour, the fluid inside the eye, as it is replenished naturally.
Laser surgery techniques
• Trabeculoplasty – a procedure, as its name implies, that opens up the trabecular meshwork, the fine mesh between iris and cornea that allows a slow drainage flow of aqueous humour from the eye.
As a temporary measure only, in this technique a laser is aimed at the mesh to improve its permeability.
50% of cases will require a repeat procedure within 5 years.
• Peripheral iridotomy – also called laser peripheral iridotomy (LPI), in this technique, which is suitable for treatment of closed angle glaucoma, a very small opening hole is made in the iris to uncover the trabecular meshwork which has been “closed” by the iris touching the lens, thereby effecting a drainage route.
The technique can be also be used in anticipation of preventing severe angle closure, and so can be a preventative measure.
• Non-penetrating deep sclerectomy – (NPDS) involves scraping a patch of the sclera just enough to allow the aqueous humour to penetrate through and so relieving pressure. This is not a common procedure.
Conventional surgery techniques
A trabeculectomy is the most widely used conventional procedure and involves cutting a small flap in the sclera, the white part of the eye, to expose the trabecula meshwork which is not functioning according to the type of glaucoma.
The small flap is sewn back, but only loosely, so that the flow of aqueous humour is increased and intra ocular pressure (IOP) reduced.
The use of implants
Implants such as stents and shunts are used to increase flow of aqueous humour and can be inserted during a procedure such as a trabeculectomy.
Made of inert materials such as silicon and hard plastics, they are extremely effective and can be a welcome release from the daily chore of applying eye drops. Downsides are that the positioning may be inaccurate and it’s difficult to change after the procedure, or they may lower pressure too much.
The most common implant is known as Ahmed Valve. These tend to be last resort devices and luckily very few glaucoma patients will require one.
What the future holds
Development of implanted sensors to monitor intra ocular pressure and thereby the progress of a glaucoma is currently proceeding in research laboratories. The continued miniaturisation of the components required such as a battery together with solar cell, radio transmitter and pressure monitor, makes for a world where anything will be possible.
And it doesn’t end there – research is underway to develop a working retina cell from embryonic stem cells – potentially this will revive lost vision which currently cannot be restored.
