Open-angle glaucoma is the most common type of glaucoma and usually appears after 50-60 years of age. It is called “open angle” because, although the angle of the cornea with the iris is adequate, the aqueous humour´s drainage channels are closed progressively, resulting in a proportional increase in intraocular pressure (IOP) as a result of which the optic nerve may be damaged.
The cause is not well understood, although it is known that there is an important hereditary factor, since people with a family history of this disease are more likely to suffer from it.
Other risk factors are high myopia, high blood pressure, low blood pressure, type 2 diabetes, smoking, or prolonged corticosteroid treatments or vasoconstrictive medications. Also, suffering from other eye diseases, such as uveitis, can lead to the development of glaucoma.
In the early stages, glaucoma may not cause appreciable symptoms except for an increase in IOP, so it is very important that once every two years after the age of 50 and annually after 60, all people undergo an ophthalmological review that enables the early detection of this disease.
If the IOP is greater than 21 mm of mercury, in the absence of impaired vision, it may indicate that the development of the disease has begun. If this is the case, it is common for progressive loss of peripheral vision to occur, and even if visual acuity is initially maintained, total loss of vision may occur.
The great challenge of open-angle glaucoma is early detection, because the earlier the disease is diagnosed, the better the treatment options. Hence the importance of regular eye examinations from the age of 50, because if the deterioration of vision is expected to occur, it means that the disease is at an advanced stage.
It is necessary to take into account that this disease is not curable, although with the appropriate treatment it is possible to control its growth and to prevent that it progresses. At first, a pharmacological treatment will be applied with the objective of reducing IOP and keeping it at normal levels, which will prevent the disease from progressing.
These drugs act by reducing the production of the aqueous humour and helping its reabsorption. However, the time may come when medication is no longer effective, in which case the treatment must be surgical, and can be performed by different techniques.
treatment and SURGERY
Trabeculoplasty is a technique in which the laser is used to increase the opening of the drainage ducts of the aqueous humour, so that it can be released and be reabsorbed with normality, which causes the IOP to be reduced and, as a result, slows down the progression of the disease.
Another option is to perform a filtration surgery, through which a new drainage duct is created, so that the aqueous humour can be eliminated through the circulatory system of the eye´s subconjunctival area. It can be achieved by different techniques such as a deep non-perforating sclerectomy and trabeculectomy.
If all these surgical procedures are not finally effective, a drainage valve may be implanted to provide an outlet for the aqueous humour and reduce IOP.
Results of the operation
The prognosis for the patient with open-angle glaucoma will depend on whether the disease is in early or advanced stages and, therefore, on the severity of the damage suffered by the optic nerve.
What has been lost can no longer be recovered, but in most cases its progression can be slowed down and blindness avoided.