Dr n. med. Justyna Kłos-Rola
Prof. Dr hab. n. med. Tomasz Żarnowski
What is it?
Glaucoma is a progressive disorder of the optic nerve that leads to irreversible damage of vision. There are two main types of glaucoma: open-angle glaucoma and narrow-angle glaucoma. Very rarely there are instances of specific types of glaucoma, such as congenital, infantile or juvenile glaucoma. Sometimes glaucoma is associated with other disorders within the eyeball, as for example, disease caused by pseudoexfoliation (PEX) syndrome (pseudoexfoliation glaucoma) or pigment dispersion syndrome (pigmentary glaucoma). Untreated glaucoma can lead to blindness.
Glaucoma can develop very slowly, over many years, painlessly damaging the optic nerve in a way imperceptible for the patient. In the case where only one eye is affected the patient may not even notice problems with vision. The problem might be detected incidentally when the healthy eye is covered or during ophthalmological examination.
However, it may also happen that the disease develops quickly. In such instance the patient loses vision in a few months. Sometimes additional sudden symptoms, called an attack of glaucoma, appear. These are associated with angle closure and include severe eye pain and headaches, nausea and even vomiting, worsening of vision, and rainbow-like halos.
The only way to detect glaucoma are regular ophthalmological examinations, particularly in the case of people with positive family history of the disease. During routine eye examination ophthalmologist examines the intraocular pressure, which is the major risk factor for the development of glaucoma and the only one that is subject to treatment. In the course of examination ophthalmologist assesses eye anatomy, filtration angle and appearance of the optic disc. In order to detect and monitor glaucoma patient should regularly perform additional examinations - visual field test and optic nerve imaging such as HRT, OCT or Gdx.
Methods of treatment
Treatment of glaucoma includes pharmacotherapy, laser therapy and surgeries that are intended to lower intraocular pressure (IOP). Therapy begins with medication and laser therapy. Surgical procedure is used in advanced cases of glaucoma and when, despite the aforementioned treatment, the disease continues to develop. Surgeries are used also in the case of the so-called normal-tension glaucoma, in which there is damage to the optic nerve despite normal intraocular pressure.
Nowadays, laser therapy is increasingly more often proposed as a first-line treatment also in the case of ocular hypertension. Although, after the surgery anti-inflammatory drugs should be taken for a couple of days, the patient can return to normal everyday activities already on the next day after the treatment. Laser therapy is also applied in cases when no control of intraocular pressure could be gained by means of medications.
Selective laser trabeculoplasty using Nd:YAG laser (SLT)
This is a safe, fast and non-invasive method. It is effective in case of open-angle glaucoma, pigmentary glaucoma, pseudoexfoliation syndrome (PEX), as well as in case of the eyes that underwent other ophthalmic procedures. The procedure is performed within the filtration angle and there is minimal tissue damage during the surgery. Usually it is completed during a single session. On average, the pressure is expected to be reduced by up to 30% and the effect
lasts 1-5 years.
A very important advantage of SLT is the possibility to repeat it, thanks to which this method became widely used in recent years. An older alternative to SLT is a classic argon laser trabeculoplasty (ALT), however, due to the tissue changes it causes, the procedure can be done only twice in a particular eye.
Iridotomy using Nd:YAG laser
This procedure is performed in case of a closed angle of filtration or a narrow one that is threatening to close as well as in acute glaucoma attack. The purpose of it is to create a hole in the peripheral iris. It is usually performed only once.
Iridotomy, alike other laser treatments, is subject to risk of transitory increase of intraocular pressure and temporary inflammation, which is the result of reaction to the treatment. It may also involve bleeding into the anterior chamber of the eye.
This procedure is the gold standard in the surgical treatment of glaucoma. The treatment is advised to patients for whom other treatments are ineffective, in the case of whom the disease is progressing or is already very advanced at the time of detection. The treatment involves creating a new channel for outflow of the fluid (aqueous humor) from the anterior chamber of the eye under the conjunctiva, which is to lower the intraocular pressure. After surgery the so called filtration bleb forms in the patient's eye.
Other glaucoma treatments include sclerectomy, canalostomy and procedures involving implants, among others, also Ahmed implant. The aim of all surgical procedures is to lower the intraocular pressure and to stop the development of the disease, and not vision improvement.