Ocular Hypertension - Causes, Symptoms, Diagnosis and Treatment
Ocular hypertension appears when the pressure inside one or both eyes exceeds the normal values, ranging between 10 and 21 mmHg in a healthy organism.
This higher than normal pressure is usually asymptomatic and triggers no serious vision problem, although it may signal an increased risk of developing glaucoma. We can therefore say elevated intraocular pressure is not a disease by itself, but a condition appearing in glaucoma suspect persons. Unlike hypertension, glaucoma is a severe eye problem in which fluid builds up inside the eye, causing damages to the optic nerve and leading to vision loss when no treatment is applied.
Who develops eye hypertension?
Ocular hypertension appears most of the times in people aged 40 or more although it can also be diagnosed in teens and adults. According to statistics, African Americans are more prone to developing this condition and people with a positive family history for eye problems such as elevated pressure or glaucoma are more likely to be affected by this symptom.
Between 4% and 10% of all adults aged 40 and more have a higher than normal intraocular pressure, with or without signs of glaucoma. Diabetes and nearsighted people are more affected by this disorder than those with normal vision and people with thinner corneas are at higher risk of developing eye hypertension. In women, this condition appears more frequent after menopause.
What causes ocular hypertension?
This condition appears whenever the balance between the production and drainage of fluids from the eyes is altered. In a healthy eye, a transparent fluid called aqueous humor circulated inside the front chamber, maintaining a proper eye moisture and pressure and ensuring a healthy vision.
For maintaining the equilibrium, an amount of fluid equal to the one produced inside the eyes has to be drained out through the drainage channels. However, in certain conditions, these tiny ducts become blocked and don’t work properly, so fluid builds up inside the eyes, raising the pressure.
Symptoms and signs of elevated intraocular pressure
In most cases the condition remains asymptomatic, meaning that sufferers don’t really experience any sign in the first stages. It is therefore impossible to realize you suffer from ocular hypertension unless the condition triggers more severe problems such as glaucoma, which manifests through distinctive symptoms.
Still, this doesn’t mean everyone who develops eye hypertension will also get glaucoma – a regular eye exam can diagnose this condition in time, restoring the normal pressure and reducing the risk of further complications.
Diagnosis of elevated intraocular pressure
The standard test performed for diagnosing this condition is called tonometry and involves the use of a special tool called tonometer. With this device the ophthalmologist examines the inner structures of your ocular globes, testing at the same time your anterior chamber, your cornea, iris and lens. You may also be asked to take a standard test for visual acuity, meant to detect problems of peripheral vision.
These exams, taken in different moments of the day, should not reveal any sign of nerve damage, eye abnormality or pressure changes so in case your measured eye pressure varies with more than 2-3 mmHg from one test to another you may be affected by glaucoma.
In case your intraocular pressure is higher than normal but no signs of damage are present, gonioscopy may be performed for checking the state of your drainage ducts. Also, the ophthalmologist may measure the thickness of your cornea using an ultrasound probe.
Ocular hypertension treatment
The recommended treatment for this condition depends on the measured intraocular pressure. For a value of 22-25 mmHg not treatment is usually prescribed although periodic tests taken at 2-3 months intervals are required. People with an intraocular pressure of 26-27 mmHg are also asked to recheck their eyes health 2-3 weeks after the first exam and in case the value is constant follow-up visits should be done once or twice a year. As for patients with an intraocular pressure of 28 mmHg or higher, medicines are generally prescribed for a one month treatment plan. After this, a recheck exam should be taken.
Topical medicines and oral glaucoma medicines such as osmotics and cholinergics are generally prescribed to people with ocular hypertension. However, most physicians prefer not to recommend such treatments unless the optic nerve is damaged and the risk of complications including glaucoma and vision loss is major.