General information about glaucoma
Glaucoma is a very heterogeneous group of chronic diseases of the eye, which are often but not always associated with increased intraocular pressure (IOP). The prevalence of glaucoma in adults >40 years of age lies between 2-4% depending on cultural background. Glaucoma is the second most common cause of blindness worldwide after cataract.
During the course of glaucoma, there is a progressive loss of nerve cells (retinal ganglion cells), which are located in the retina of the eye. The retinal ganglion cells have processes (axons) that join together in the optic nerve to leave the eye in a bundle. The optic nerve transmits the signals generated by inciting light in the retina to the brain, where, after further processing, the image seen by the eye is formed in the consciousness of the observer. If these retinal ganglion cells are lost in the course of glaucoma, defects in the visual field develop, which are usually localized paracentrally in the beginning, but increase in size during the course of time and can remain unnoticed for a long time. If left untreated, glaucoma can lead to blindness in one or both eyes.
The reduction of intraocular pressure is the only known risk factor, which can be positively influenced by medication or surgery. Up to now, there are no therapeutic possibilities to repair damages that have occurred in the course of glaucoma. At best, a further progression of the disease can be slowed down or at best stopped. Furthermore, in many cases the course of the disease is usually asymptomatic for a long time. Therefore, from the age of 40 - 50 years, regular check-ups with an ophthalmologist are recommended in order to detect a possible glaucoma at an early stage. The earlier glaucoma is detected, the better it can be treated in most cases, so that functional blindness, which used to be very common, can fortunately be averted in most glaucoma cases today.
A variety of therapeutic options are currently available for the treatment of glaucoma. As mentioned above, lowering IOP is the only proven therapeutic option for the treatment of glaucoma. In most cases, IOP is first treated with locally applied IOP-lowering eye drops. If this does not lead to a sufficient reduction of IOP or if the disease continues to progress under the given therapy, glaucoma surgery is indicated. In the case of particularly elevated IOP values, obstructed chamber angle structures or the existence of intolerances and allergies to the prescribed eye drops, glaucoma surgery may be recommended in individual cases.
As described above, glaucoma is a very heterogeneous group of diseases with many different forms and subtypes. A comprehensive enumeration of all known forms of glaucoma can not be given here. Furthermore, glaucoma can also develop in the course of other eye diseases (secondary). However, the therapy may differ significantly depending on the present type of glaucoma. A particular drug or surgical technique may be well effective in a certain form of glaucoma, but ineffective or even obsolete in others. Therefore, a thorough consideration of the available findings and, unfortunately, relatively frequent repetitions of various examinations is necessary in order not to overlook any detail that is important for the therapy.
Intraocular pressure can be lowered by reducing the production of aqueous humor or by improving the outflow of aqueous humor from the anterior chamber of the eye. There are a large number of different medications available for this purpose, containing single active ingredients or combinations. In most cases they are applied locally as eye drops and the active ingredient diffuses from the ocular surface into the interior of the eye to exert its specific effect there.
In most cases, glaucoma is initially treated with medication. If medical therapy does not show any or no sufficient efficacy or is not well tolerated by the patient due to allergic reactions or other side effects, the indication for glaucoma surgery is given in a second step. As mentioned above, the goal of glaucoma surgery is to lower intraocular pressure. This can be achieved by lowering aqueous humor production or by improving aqueous humor outflow from the eyes interior.
Reduction of aqueous humor production:
- (micropulse) cyclophotocoagulation
Improvement of aqueous humor outflow:
- Argon laser trabeculoplasty
- YAG laser iridotomy
- Selective Laser Trabeculoplasty
- Minimally Invasive Glaucoma Surgery (iStent, XEN-Microstent, Preserflo, Starflow implants)
- Deep sclerectomy
- Viscocanalostomy & Viscocanaloplasty
- Tube shunt implants (Ahmed, Baerveldt)
At the University Eye Hospital Bern all above mentioned surgical procedures are offered and performed regularly and in large numbers. In addition, glaucoma patients are seen in our clinic for check-ups at regular intervals. During these check-ups, functional tests (visual field examinations), intraocular pressure measurements (by means of different procedures) as well as different modes of documentation of findings (photo, OCT, HRT) are performed in order to detect glaucoma progression at an early stage.