What is ocular hypertension?
Ocular hypertension occurs when the pressure inside the eye exceeds the range considered normal and goes higher than 21 mm Hg.
The increase in intraocular pressure (progressive with age, although may also be due to other disorders or causes) is the main risk factor for developing glaucoma and, therefore, people with ocular hypertension are more likely to suffer the disease. However, the two are different: ocular hypertension means that the intraocular pressure is high but the optic nerve is not damaged, whereas with glaucoma, the optic nerve has been damaged - and intraocular pressure might be normal or high - which can lead patients to notice a loss of visual field and even central vision in advanced stages of the disorder.
What causes it?
Ocular hypertension is caused by a malfunction of the drainage system for the aqueous humour, the fluid whose function is to bathe and nourish the ocular structures. When it does not flow correctly for different reasons, the balance between the fluid produced inside the eye and the fluid released from it is broken, leading to an increase in intraocular pressure (normally gradual, although it may also be sudden).
Although anyone can suffer from ocular hypertension, certain groups are more likely to suffer from it and, therefore, to develop glaucoma:
- People with a family history of ocular hypertension or glaucoma
- The over 60s
- The very short- and far-sighted
- Patients with certain ocular trauma or diseases
- Black and Asian people
- Patients with a narrow ocular angle
How can it be prevented? Symptoms
Ocular hypertension cannot be prevented, but it can be closely controlled with regular check-ups (especially in the case of risk factors) and reduced by different treatments to avoid damage to the optic nerve and an irreversible loss of vision as a result of glaucoma.
The increase in intraocular pressure goes unnoticed in patients and no symptom is manifested (except for the sudden onset of acute glaucoma, which causes intense pain). Therefore, the only way of detecting ocular hypertension is through a comprehensive eye examination in which the value of the intraocular pressure is measured using a test known as tonometry.
When ocular hypertension causes glaucoma (i.e. it damages the optic nerve), this also generally goes unnoticed if an examination is not performed, as the decrease in vision is often peripheral at the start of the disease and does not become obvious until it is in very advanced stages.
The treatment of ocular hypertension, individualised according to each case, can be through drugs (different types and combinations of eye drops), laser (trabeculoplasty) or various surgical techniques that seek to achieve an effective reduction of intraocular pressure with the least impact for the patient.