It is a disease that affects the optic nerve.  Its major risk is the increase of the intraocular pressure, which we can control (IOP).
Early detection is fundamental.

Normal nerve

Glaucoma nerve

Definition:

Glaucoma is a group of diseases that cause visual field loss due to optic nerve atrophy. Elevated intraocular pressure is considered to be its main risk factor.

Aqueous humor is a liquid produced in the eye, in a structure called cilliary processes. It is excreted through the trabecular meshwork, in an angle between the iris and the cornea.

There are many types of glaucoma. Glaucoma can be open angle or angle closure, and primary or secondary to other ophthalmic diseases. Primary open angle is the most frequent type of glaucoma. World Health Organization reports an incidence of 2 million new cases per year

Those people who have relatives suffering from glaucoma are at higher risk of having the disease. Many genes related to glaucoma have been identified. Some examples are TIGR, GLC1A, GLC1B and GLC1C.

Glaucoma usually appears in adult people (mostly over 40). However there also exist congenital, childhood and juvenile glaucoma.

 

Diagnosis:

People suffering from glaucoma experiment an irreversible slowly progressive visual field loss. The patient does not perceive this loss until glaucoma gets to advanced stages in which peripheral vision is very reduced.

A basic ophthalmic evaluation is usually enough to diagnose it.  There are some useful tests that help to its diagnosis and follow up. Some of them are:

– Optic disc photography:  a picture of the fundus helps us in the assessment of the classical morphologic signs of glaucomatous optic neuropathy. We are able to detect optic nerve changes in time through taking serial pictures.

– Pachometry: It is used to measure corneal thickness, so we can have more accurate intraocular pressure estimation. Moreover, having a thin cornea has been established as an independent risk factor for glaucoma.

– Automated perimetry: It analyzes the visual field of both eyes in order to detect deficiencies and register their progression through time.

– Optical Coherence Tomography (OCT):  This test uses light to obtain sectional images of various eye structures. OCT detects the loss of retinal nerve fiber layer that happens in glaucoma. Macular ganglion cell complex measurement is also useful in the diagnosis of glaucoma.

Oct Normal

 

Oct Glaucoma

 

Treatment:

Glaucoma treatment is oriented to lower intraocular pressure, to improve intraocular blood flow and to minimize oxidative stress. To achieve it, the following treatments are available:

– Eye drops: there are different medications to decrease intraocular pressure. These medical agents act reducing aqueous humor secretion and/or increasing uveoscleral outflow. These drugs are prostaglandins, alpha-agonists,  beta-adrenergic antagonists and carbonic anhydrase inhibitors.

– Laser procedures: laser iridectomy and iridoplasty are performed in order to prevent or revert a pupillary block in eyes considered at risk (narrow angle). Trabeculoplasty can lower intraocular pressure in some cases of open angle glaucoma.

– Surgery:  surgical procedures are performed in order to reduce intraocular pressure when patients do not tolerate or do not respond to medical therapies. The main goal of these procedures is to communicate intraocular and subconjunctival spaces  in order to let aqueous humor flow. The most used techniques are trabeculectomy, non-penetrating deep esclerectomy and drainage devices implantation. Diode laser ciliary body ablation is indicated to lower intraocular pressure in eyes that have poor visual potential or are poor candidates for incisional surgery.

– Neuroprotection: there are some products that can have a beneficial effect on the optic nerve by reducing oxidative stress. Some examples are gingko biloba, antocianins (cranberries) and epiverve (tea).

 

Conclusions:

People suffering from glaucoma are not aware of their visual field loss until advanced stages.

An early diagnosis is very important, given that glaucoma is an irreversible and highly prevalent disease.

Important vision loss or blindness can be avoided if an early diagnosis and a correct treatment are performed

Medical follow up is recommended for everyone older than 40. People who have relatives suffering from glaucoma should be evaluated before.