Glaucoma
It is a disease that affects the optic nerve. The main risk factor that you have and that we can control is the increase in intraocular pressure (IOP).
Early detection is critical.
Definition and type
Glaucoma is a set of diseases that have as a common feature an atrophy of the optic nerve with a loss of visual field. Increased intraocular pressure is the main risk factor.
Aqueous humor is a liquid that occurs inside the eye, in a structure called ciliary processes, and is removed by the trabecular meshwork. This mesh is located in an area that forms an angle between the iris and the cornea.
Glaucoma can be open or closed angle, and can also be primary or secondary to other ophthalmic pathologies. Primary open-angle glaucoma is the most common type of glaucoma, with the World Health Organization estimating an incidence of more than 2 million new cases each year.
Having a family member with glaucoma increases your risk of developing it. Several genes related to glaucoma have been identified, such as the TIGR gene, GLC1A, GLC1B, GLC1C, etc.
Glaucoma usually appears in adulthood (from the age of 40), although there are cases of congenital, childhood and juvenile glaucoma.
Diagnosis
Glaucoma manifests itself clinically as a slow, progressive, and irreversible loss of visual field that is not perceived by the patient until it reaches advanced stages, in which peripheral vision is already greatly reduced.
A basic ophthalmological check-up makes it possible to diagnose this pathology in most cases. Apart from the ophthalmological examination, there are different complementary tests that help us to diagnose and monitor this disease. Some of them are:
- Retinography: is a photograph of the fundus that allows us to document the appearance of the optic nerve and detect possible changes over time.
- Pachymetry: allows to measure the thickness of the cornea and correctly estimate the intraocular pressure. In addition, having a thin cornea has been established as an independent risk factor for glaucoma.
- Automated perimeter: analyzes the field of view of each eye to detect defects and monitor their progression over time.
- Optical coherence tomography (OCT): uses light to obtain sectional images of various structures of the eye. In glaucoma there is a loss of peripapillary nerve fibers and OCT allows us to detect this alteration. Recently, OCT analysis of macular ganglion cells has been shown to be useful in the diagnosis of glaucoma.
Treatment
Glaucoma treatment is aimed at lowering intraocular pressure, improving eye flow, and reducing oxidative stress. To do this, we have several tools:
- Eye drops: There are several types of drugs that aim to reduce intraocular pressure, either by reducing the production of aqueous humor or increasing its drainage. The different families of drugs used are prostaglandins, alpha-agonists, beta-blockers and carbonic anhydrase inhibitors.
- Laser procedures: Iridotomy and iridoplasty are performed to prevent or reverse a blockage of the aqueous humor when the trabecular angle is narrow. Trabeculoplasty manages to reduce intraocular pressure in some cases of patients with open-angle glaucoma.
- Surgery: Surgical procedures are intended to reduce intraocular pressure in refractory cases or if an intolerance to medical treatment appears. These techniques have as their main goal to create a drainage of aqueous humor from the intraocular space to the subconjunctival space. The most commonly used surgical techniques are trabeculectomy, deep non-perforating sclerectomy, and implantation of valvular devices. Cyclophotodestration of the ciliary body with diode laser is proposed as an alternative in complex and advanced cases.
- Neuroprotection: There are different products with antioxidant action that can have a beneficial effect on the optic nerve by reducing oxidative stress. Some examples are gingko biloba, anthocyanins (blueberries) and epinerve (tea).
Conclusions
Patients with glaucoma do not perceive the loss of visual field until very advanced stages.
Given that glaucoma is a highly prevalent and irreversible disease, an early diagnosis is vital.
With an early diagnosis and appropriate treatment we can avoid a significant loss of vision that, in the worst case, can lead to blindness.
Regular check-ups are recommended for everyone over the age of 40, and earlier if there is a family history of glaucoma.