What is glaucoma?

Glaucoma is a chronic irreversible optic nerve disease due to many reasons, the most important risk factor of which is high intraocular pressure (IOP). 

It is the second cause of blindness in the western world and 50% of people suffering from it in the developed world are unaware of it.

We speak of glaucoma when we find that the optic nerve (which acts as a conductor of information from the eye to the brain) is affected. However, we talk about ocular hypertension when IOP alone is high, without any optical nerve defect. 

IOP is determined by the production of aqueous humour (the liquid responsible for the eye's tone) and the resistance and difficulty involved in its drainage. 

There is a wide variety of types of glaucoma although in general terms we can classify them according to their origin (primary and secondary) and angle width (open- or closed-angle)


The majority of those affected do not usually show symptoms until the advanced stages of the diseases, when the eye damage is then significant.

This happens because of a loss of lateral vision, which the patient does not notice because the brain has the ability to compensate for the lost vision and fill in the blind spots by combining the images in both eyes to give a complete image. 

This is why it is called 'the silent thief' and early detection is crucial. 

How is it diagnosed?

  • With an IOP (intraocular pressure) measurement
  • With the visual field
  • With an optical coherence tomography (OCT) 

Diagnosis is vitally important given that it is a chronic disease that hardly has any symptoms until it is at a very advanced stage, when the patient has tunnel vision. 

Glaucoma risk factors

  • Ocular hypertension
  • Over the age of 40
  • Family history

Factors that may condition the progression of glaucoma

  • High blood pressure or vascular diseases 
  • Myopia
  • Diabetes


The majority of treatments are aimed at increasing drainage and, in some case, reducing the production of aqueous humour. 

There are three main treatments, described herein from least to most invasive: 

Medical-drug treatment

  • Hypotensive eyedrops
  • Tablets

Outpatient laser treatment

  • Laser iridotomy
  • Trabeculoplasty
  • Transscleral diode laser cyclophotocoagulation 


  • Microinvasive surgery (MIGS)
  • Invasive surgery for more advanced cases 
  • Filtering surgery (trabeculectomy and a non-penetrating sclerectomy
  • Drainage devices (Ahmed and Baerveldt valves)

Early detection and timely treatment considerably improve the visual prognosis and prevent it progressing towards blindness. 

Professionals who treat this pathology

Frequently asked questions

  • Yes, glaucoma in one eye is possible. It may be a consequence of a traumatic event or uveitis, for example. In addition, glaucoma is a asymmetric bilateral disase, that is to say, it does not manifest itself in the same way in both eyes. 

  • At present, there is no cure for this disease, but early diagnosis and correct treatment help to delay its onset.

  • Although glaucoma usually occurs to people over the age of 60, even a baby could get glaucoma

  • The effects of glaucoma are irreversible. Once the vision is lost, it cannot be restored.

    Irreversible, glaucoma is the main preventible cause of blindness. It is commonly known as the silent thief because it advances quickly without any apparent symptoms, leaving the majority of people with undiagnosed glaucoma. 

  • Glaucoma is a slowly progressive "optic" neuropathy, which, in the majority of cases, is due to high intraocular pressure (IOP). The monitoring of glaucoma is fundamentally based on reducing IOP. The most common treatments for glaucoma are eyedrops which have to be used every day and continuosly to keep the IOP within the recommended limits for each case. Other methods of treatment include laser treatment or surgery when the eyedrops are no longer effective. There is no definitive treatment for glaucoma, in fact, glaucoma is only under control—but not cured—when the IOP has dropped to safe levels.