What is Glaucoma?
Glaucoma is known as a silent disease because it has no noticeable symptoms until the disease is well advanced and late detection may lead to total loss of vision.
While there are many causes and the exact pathophysiology remains a mystery for ophthalmology, glaucoma is a disease characterized by a pathological increase in intraocular pressure (IOP) leading to damage of the optic nerve (optic disc) that is also reflected in a characteristic loss of visual field because of the loss of ganglion fibers.
The American Academy of Ophthalmology currently defines glaucoma as a progressive multifactorial optic neuropathy. That is, a condition of the optic nerve caused by multiple factors including IOP.
Though glaucoma is a silent disease, some symptoms may include seeing halos around lights, headaches, nausea, fatigue in setting and changing of glass lenses.
When glaucoma is detected early, chronic elevation of IOP affects the optic nerve that anatomically shows an increased normal excavation due to loss of nodal fibers and functionally manifest with the presence of scotomas in the visual field of the affected eye. These alterations are not detected by the patient at first because the defects are often to the side or peripheral, not affecting central vision until the final stages of the disease when it is too far advanced and the loss of every ganglion fibers is very important.
This loss of fibers and visual ability is not recoverable in glaucoma. In the best case scenario, the loss can be stopped at the time of diagnosis and treatment, but not recovered. This is why early diagnosis of the disease, which is key to improving prognosis, progression and the quality of life of patients affected by glaucoma, is essential.
It is very important to obtain an early diagnosis of glaucoma; that which makes up part of the basic eye examination performed by the specialist to patients, tonometry (IOP measurement), examination of the optic nerve in the back of the eye and evaluation of the same function through evaluation of the visual field.
There are different types of glaucoma
There are different types of glaucoma that will vary in their progression and treatment. Glaucoma is basically divided into primary, secondary and congenital groups. They can also be classified into open-angle glaucoma or narrow angle depending on the anatomy of the inner chamber that can be evaluated with an exam called gonioscopy.
The most common type of glaucoma is the first one called primary open angle which is hereditary and appears in adult life, usually after age fifty. It’s progress is a slow and silent type, but leads to blindness without treatment.
The percentage of primary narrow angle glaucoma is less and is characterized by acute closure of the inner chamber which generates an abrupt increase in IOP to very high values (60 or more millimeters of mercury). This IOP can cause symptoms such as pain, headaches, vomiting, blurred vision or almost no vision. These attacks of acute glaucoma represent true ocular emergencies and should be treated as soon as possible.
The most common types of secondary glaucoma are those which are traumatic, with cortisone and by capsular pseudoexfoliation glaucoma. They can also be caused by ocular inflammations such as uveitis, systemic diseases, intraocular tumors, extra-ocular venous blockages, etc. ….
Another possible cause of secondary glaucoma is related to alterations of the lens: from the same rupture and the release of substances that can produce facoanafiláctic and phacolytic glaucoma. For the position of the lens, can yield a facotópic glaucoma. Depending on the thickness of the lens, it can produce an acute glaucoma because of a pupillary block.
Other causes are given by the formation of anterior peripheral synechiae, central posterior synechiae, venous occlusions in the posterior segment or presence of proliferative diabetic retinopathy (neovascular glaucoma).
As for congenital glaucoma, these tend to occur during the seventh month of intrauterine life and expressed within the first days to months of life. It is essential to recognize earlier, the signs and symptoms of the disease from the pediatrician and/or eye pediatrician. Especially since the therapeutic success is directly related to early diagnosis and treatment. The latter is always surgery (trabeculectomy: placing valves in refractory cases) and should be done as soon as possible, after studying the patient under general anesthesia.
There are several syndromes that are often associated with ocular syndromes and / or systemic syndromes: Sturge Webber Syndrome, Axenfel-Rieguer syndrome, Peters syndrome, Clipper Trenaneau Syndrome, Stickler syndrome, metabolic abnormalities, etc…
The basic eye examination consists of measuring visual acuity without correction of the near and far vision, measuring the intraocular pressure (IOP), observation of the fundus (especially the optic nerve head or papilla), gonioscopy (to evaluate chamber angle) and a visual field assessment.
Doing it like this you can diagnose this condition so that later you can study it in more detail. For this it is indicated: pachymetry, which measures the corneal thickness, provocation tests (to see how much increased IOP), ultrasound scan of the optic nerve, among others, according to the nature and progression of the glaucoma.
All of these complementary studies to help diagnose and monitor the disease and may be able to highlight risks, progression and customize your treatment.
Glaucoma can not be cured, it is stopped. Early diagnosis is very important and also to detect it in the early stages of the disease.
Depending on the type and stage of glaucoma, the types of treatments provided will vary and may include:
– Topical or drug treatment: daily application of eye drops to diminish IOP. There are many drugs that can be used separately or that can be combined.
When the pharmacological treatment of glaucoma is not effective, other techniques can be used:
– Laser Treatment: The most common technique is the Argon laser trabeculoplasty is used to enlarge the duct of the eye in order to help control IOP. In the case of narrow-angle glaucoma the YAG laser is used to perform an iridotomy (drainage channel in the iris).
– Surgical treatment: traditional surgery is surgical trabeculectomy to create a new drainage channel for the aqueous fluid to leave the eye and thus generating a lower glaucoma IOP. In more advanced and / or refractory glaucoma the placement the of intraocular valves can be implemented.