Treatment of glaucoma
Indications for treatment
As a general law, all glaucomas must be treated. In most cases, eye drops are sufficient for lowering ocular pressure and stopping the evolution of the disease.
Nevertheless, in certain cases, laser treatment or surgery is necessary.
After glaucoma surgery, it is sometimes possible to stop glaucoma drops if the eye pressure is controlled by the surgery.
Treating ocular hypertension
Elevated intraocular pressure without damage to the optic nerve, “ocular hypertension”, is the principal risk factor for developing glaucoma. It is often desirable to treat this ocular hypertension with eye drops.
Sometimes, when the ocular hypertension is not very high and there are no other risk factors, it is possible to follow the ocular hypertension without initiating drug therapy. We do not treat systematically all patients with ocular hypertension.
There are 3 main types of treatment that allow to reduce the intraocular pressure.
Depending on the pharmacology of the eye drops, they will accelerate the quantity of liquid that is drained from the eye and/or reduce the quantity of liquid produced by the eye.
There are different types of laser adapted on the different forms of glaucoma (Argon laser, YAG laser, Diode laser).
Surgery is necessary to lower the intraocular pressure, if the disease continues to progress.
The eye drops
There are several different therapy classes that allow us to drop the intraocular pressure. The anti-glaucoma eye drops have 2 different effects, either they drop the production of aqueous humour (beta-blockers, alpha-adrenergic agonists, carbonic anhydrase inhibitors), or they increase elimination of aqueous humor from the eye (prostaglandines, miotics).
- Carbonic anhydrase inhibitors
- Alpha-adrenergic agonists
- Miotics (pilocarpine for example)
The efficiency of the treatment is judged by visual field and optic nerve exams as well as intraocular pressure. The purpose is to preserve vision. Only an ophthalmologist after examining the eye and reading the visual field can say whether the disease is stabilised.
Eye drops tolerance
A poor eye drop tolerance may occur immediately or after several months or years.
The principal signs of local intolerance is a sensation of eye burning or tingling that lasts more than 10 minutes after the instillation, eye redness and eye pain. In certain cases, the eyelids are sensitive, red and swollen.
Your doctor can modify treatment if you develop intolerance.
Eye drops side effects
An eye drop can sometimes be responsible for general systemic effects. Even in small concentrations, an instilled drug in the eye can get in the systematic circulation and have side effects.
The nature of the side effects depends on the eye drops used, but it is possible to observe:
- general tiredness
- difficulty breathing, asthma
- dryness of the mouth and nose
By gently pushing the inside corner of the eye, close to the nose or by closing the eyelids once instilling the eye drops, it is possible to decrease the amount of drop that is absorbed, and thus decrease the risk of general side-effects.
Eye drops and contact lenses
Certain eye drops decrease the secretion of tears and can make wearing lenses very uncomfortable. Certain preservatives in eye drops can damage the material of the lenses.
The current generation of contact lenses are more resistant and the damage risk is reduced if the lenses are change regularly. Soft lenses tolerance is worse if tear secretion is decreased.
After surgery, wearing lenses should be stopped until the surgeon gives the OK, usually a few weeks..
The laser is a strong and concentrated light beam, which allows cutting and burning of human tissues.
The laser is an ideal instrument for the treatment of ocular diseases since the eye structures are transparent and allow the emission of the laser beam. Lasers offer the possibility of performing ocular surgery without incisions, eliminating the risk of infections and minimizing the risk of haemorrhage. Different types of lasers exist depending on the nature of the gaz (Argon, Yag) used to concentrate the light rays emitted.
Laser surgery is painless most of the times and does not create any visible wound. The laser procedures take place under local anesthesia. Lasers can create mild inflammation, which is usually temporary and well controlled with topical anti-inflammatory drops.
Laser treatment for acute glaucoma and angle closure glaucoma
In acute glaucoma and angle closure glaucoma, the iris blocks the circulation of the intraocular fluid, the aqueous humour, which gives the eye its pressure. The laser treatment (Yag laser) aims to create an orifice in the periphery of the iris (coloured part of the eye), in order to improve the circulation and lower the eye pressure.
Laser treatment for open angle glaucoma
The laser used for the treatment of open angle glaucoma is the Argon laser or other lasers with similar frequency. In open angle glaucoma, the pressure elevation is due to a decrease in the porosity of the aqueous humour drainage system, the trabeculum.
In open angle glaucoma, the laser is applied to the trabeculum, which contracts as a result of the thermal laser energy. The procedure is called trabeculoplasty and is performed under topical anaesthesia, without requiring patient admission to the hospital. The laser treatment is a safe method, which can be repeated if pressure creeps up again in the future.
The diode laser
The diode laser is usually performed in glaucomas resistant to the conventional medical and surgical treatment. The aim of this laser is to create some damage at the level of the ciliary processes, which they secrete the aqueous humour.
The diode laser is reserved for the advanced stages of the disease, when previous surgical techniques have failed to reduce the eye pressure. The diode laser should be used with precaution, as it might lead to very low pressure and ocular atrophy.
Glaucoma surgery is usually indicated when the eye pressure is not well controlled and the visual field gets worse despite maximum medical or laser therapy and when there is intolerance to topical treatment with drops. Many surgical techniques have been used for the treatment of glaucoma. They all aim to reduce the intraocular pressure and stabilise the glaucoma damage.
In most cases, they aim to create a new passage to facilitate the drainage of the aqueous humour. Those operations have different names depending the surgeon’s choice and experience for the particular case of glaucoma: trabeculectomy, viscocanalostomy, sclerectomy. Those surgical procedures can be completed with the use of anti-scarring agents, like mitomycine C and 5-fluorouracile, especially in complex cases. It is possible that micro-drains or valves may be used, especially in eyes, which have been previously operated with the conventional procedures.
Glaucoma surgery is performed under local anesthesia in the majority of cases and is painless. Rarely, admission to a clinic might be required for the first night after surgery.