Your intraocular pressure is one thing your eye doctor regularly evaluates during your routine eye checkup. Your eyes are under pressure, as you can see. It provides a crucial image of the condition of your eyes and can look for indications of optic nerve injury that might impair your vision.
Your eyeballs are inflated like a ball because of the fluid that fills them. Everybody's normal ocular pressure is different and might alter throughout the day. In eyes that are healthy, the fluids flow easily to maintain a constant eye pressure.
Ocular hypertension is characterized by elevated intraocular pressure. Millimeters of mercury are used to assess eye pressure (mmHg). 10 to 21 mmHg is the normal range for ocular pressure. Ocular hypertension is an eye pressure of greater than 21 mmHg.
Ocular hypertension usually has these signs:
A minimum of two doctor visits with an intraocular pressure in one or both eyes more than 21 mmHg.
The optic nerve seems to be healthy.
Visual field testing, a test to evaluate your peripheral (or side) vision, reveals no glaucoma symptoms.
There are no indications of any eye diseases.
It is incorrect to classify ocular hypertension as a disease in and of itself. But, if you already have it, glaucoma may be more prone to strike. Almost 120,000 Americans are legally blind as a result of glaucoma, which is predicted to affect 3 million Americans by 2022. These data highlight the importance of identifying and closely monitoring persons who are susceptible to glaucoma, especially those who have ocular hypertension.
According to studies, 4%–10% of Americans over the age of 40, or 3-6 million people, have intraocular pressures of 21 mm Hg or greater. Research conducted in the past 20 years have aided in defining those who have ocular hypertension:
Over a five-year period, their projected average chance of acquiring glaucoma is 10%. If ocular pressure is controlled with medication or laser surgery, this risk may drop to 5% (a 50% reduction in risk). However, due to notably improved methods for detecting glaucomatous damage, the risk may drop much lower than 1% annually. This would make it possible to begin treatment much sooner, before visual loss sets in.
Individuals with thin corneas may have an increased chance of developing glaucoma. Your corneal thickness may therefore be measured by your eye specialist.
Those with ocular hypertension have an incidence of glaucomatous damage during a 5-year period that is roughly 2.6–3% for intraocular pressures between 21–25 mmHg, 12–26% for intraocular pressures between 26–30 mmHg, and around 42% for intraocular pressures over 30 mmHg.
A retinal vein blockage, which can cause vision loss, can occur in the retinal veins in about 3% of persons with ocular hypertension. As a result, it is frequently advised that those with ocular hypertension who are older than 65 years old maintain pressures below 25 mmHg.
While some studies showed no difference, some have found that the average intraocular pressure is higher in Black and Hispanic people than it is in white people.
African Americans with ocular hypertension had a five-fold higher risk of developing glaucoma than white people did, according to a four-year study. African Americans may have a higher risk of developing glaucoma due to the average thinness of their corneas, which can lead to inaccurately low pressure readings during office visits.
In addition, primary open-angle glaucoma is thought to be three to four times more common in African Americans. They are also thought to have a higher risk of optic nerve injury.
While some research have found that women have an average intraocular pressure that is much higher than men's, other investigations have found no difference between men and women.
According to certain research, women may be more susceptible to developing ocular hypertension, particularly after menopause.
Additionally, research suggests that men with ocular hypertension may be more susceptible to glaucomatous damage.
Just as glaucoma becomes increasingly common as people age, intraocular pressure slowly increases with age.
Age is a risk factor for both primary open-angle glaucoma and ocular hypertension.
Concern should be expressed if a young person has elevated eye pressure. A young individual is more likely to sustain optic nerve damage and is exposed to high pressures for a longer period of time throughout their lifetime.
Ocular Hypertension Causes
An imbalance in the production and outflow of fluid from the eye leads to high pressure inside the eye. The fluid-draining channels that ordinarily exist in the eye do not work properly. Although more fluid is being produced, it cannot drain. As a result, there is more fluid inside the eye, which raises the pressure.
Consider a water balloon as another method to visualize high pressure inside the eye. The pressure inside the balloon increases as additional water is injected into it. With too much fluid inside the eye, the same thing happens: the more fluid, the higher the pressure. Additionally, excessive pressure can harm the optic nerve in the eye, just as too much water can cause a water balloon to rupture.
Eye pressure measurements are frequently at or slightly over the high levels of normal in people with exceptionally thick but normal corneas. While measurements are being taken, the thick corneas give a falsely high reading even if their pressures may actually be lower and normal.
Ocular Hypertension Symptoms
The majority of patients with ocular hypertension exhibit no symptoms. In order to rule out any optic nerve damage from the high pressure, routine eye exams with an eye doctor are crucial.
Questions to Ask the Doctor
Is my eye pressure elevated?
Are there any signs of eye damage due to an injury?
Has my optic nerve been damaged?
Is my peripheral vision normal?
Is treatment necessary?
How often should I get follow-up examinations?
Exams and Tests
A glaucoma test is performed by an eye doctor to determine intraocular pressure and rule out early primary open-angle glaucoma or secondary glaucoma causes.
Your doctor will have you read letters from across the room while using an eye chart to test your visual acuity, which refers to how clearly you can see an object.
Using a specialized microscope known as a slit lamp, the front of your eyes—including the cornea, anterior chamber, iris, and lens—are inspected.
Tonometry, a test used to detect ocular pressure, will be performed by your doctor. At least two or three measurements are taken for each eye. Measurements may be made throughout the day because intraocular pressure changes from hour to hour (e.g., morning and night). A 3 mmHg or greater pressure difference between the eyes may indicate glaucoma. The likelihood of developing early primary open-angle glaucoma increases if the intraocular pressure is continually rising.
Every optic nerve is checked for injury or other irregularities. Your pupils may need to dilate for this. For future reference and comparison, photographs of your optic disk—the anterior portion of your optic nerve—are obtained.
To examine your eye's drainage angle, a gonioscopy is done. An exclusive contact lens is applied to the eye to achieve this. This examination is crucial to detect whether the angles are open, constricted, or closed as well as to rule out any other conditions that can result in an increase in intraocular pressure.
Your peripheral (or side) vision is tested during a visual field test, usually with the use of an automated visual field machine. This examination is carried out to rule out any glaucomatous visual field abnormalities. It might be necessary to repeat the visual field tests. The test may only be carried out once a year in cases where there is a low risk of glaucomatous damage. The test could be done as frequently as every two months if there is a substantial risk of glaucomatous damage.
An ultrasonic probe measures your pachymetry, or corneal thickness, to confirm the precision of your intraocular pressure readings. Whereas a fat cornea can read mistakenly high pressure, a thin cornea can read falsely low pressure.
Ocular Hypertension Treatment Self-Care at Home
Using the medication correctly and following your doctor's instructions are crucial if your eye doctor has prescribed medication to assist relieve the pressure inside your eye. If you don't, your intraocular pressure may rise even more, causing permanent vision loss and damage to your optic nerve (from glaucoma).
Medical Treatment
The purpose of medical therapy is to lower the pressure before it results in glaucomatous visual loss. Those who are thought to be most at risk for developing glaucoma and those who exhibit symptoms of optic nerve damage are always put into medical therapy.
Your eye specialist will treat you in a very personalized manner. Based on your specific circumstance, you might receive medical treatment or simply be monitored. The advantages and disadvantages of medical intervention versus observation will be covered by your doctor.
Some ophthalmologists use topical medications to treat all increased intraocular pressures more than 21 mmHg. Some people wait to seek medical attention until there is proof of optic nerve injury. Because there is a substantial danger of optic nerve injury, the majority of eye doctors will treat you if your pressures are routinely greater than 28 to 30 mmHg.
Your eye doctor will probably begin medical therapy if you experience symptoms like halos, impaired vision, or pain, or if your intraocular pressure has recently increased and keeps rising over time.
Your intraocular pressure is periodically assessed using criteria like these:
You are given medication if your intraocular pressure is 28 mmHg or above. You have a follow-up appointment with your eye doctor after taking the medication for one month to determine whether it is lowering your blood pressure and whether there are any negative effects. Every three to four months, follow-up visits are planned if the medication is effective.
After 2-3 weeks following your initial appointment, the intraocular pressure is examined again, often at a different time of day, if it is between 26 and 27 mmHg. Follow-up appointments are planned every three to four months if your blood pressure reading at your second visit is still within 3 mmHg of the reading from your first visit. Your eye doctor will decide how long it will be between follow-up visits if the pressure is reduced on your second visit. Your optic nerve is checked, and your visual field is tested, at least once every year.
The intraocular pressure is measured again every 2-3 months, sometimes at a different time of day, if it is 22–25 mmHg. Your next appointment, which will include a visual field test and an examination of the optic nerve, is in 6 months if the pressure at the second visit is still within 3 mmHg of the reading at the first appointment. Testing is conducted at least once each year.
The following explanations may also warrant scheduling follow-up visits:
Repeat exams are conducted during upcoming office visits if a visual field fault is discovered during a visual field test. A visual field defect is frequently watched by an optometrist since it could be an indication of primary open-angle glaucoma in its early stages. You should therefore give the visual field exam your all because the results may determine whether you need to start taking eye pressure-lowering medication. Tell the technician to stop the visual field test if you start to feel weary so you can take a break. In this manner, a visual field test that is more accurate can be acquired.
If your intraocular pressure considerably increases or if you are receiving treatment with miotics, a gonioscopy should be done at least once every one to two years (a type of glaucoma medication).
If the appearance of the optic nerve/optic disk changes, more photos of the back of your eye are obtained.
Medications
Although no medication possesses all of the aforementioned qualities, the ideal therapy for treating ocular hypertension should successfully lower intraocular pressure, be free of adverse effects, and be affordable with once-daily administration. Your eye doctor considers these aspects in order of importance when selecting a medication for you based on your unique requirements.
To assist lower elevated intraocular pressure, medications are typically provided in the form of medicated eyedrops. Several medications may occasionally be required.
Your eye doctor might recommend using the eyedrops in just one eye at first to gauge how well the medication lowers intraocular pressure. If it works, your doctor will probably instruct you to apply the eyedrops to both eyes.
You visit your eye doctor on a regular basis for checkups after receiving a prescription for medication. Typically, the initial follow-up appointment occurs 3 to 4 weeks after starting the medication. To make sure the medication is lowering your intraocular pressure, your pressures are measured. You are examined again 2-4 months after taking the medication if it is effective and not having any negative side effects. You will stop taking the medication and be prescribed a new one if it is not lowering your intraocular pressure.
Your eye doctor keeps a watch out for any drug allergies during these follow-up visits. Be cautious to let your eye doctor know if you experience any adverse effects or symptoms while taking the medication.
Ocular hypertension is typically replaced by early primary open-angle glaucoma if the pressure inside the eye cannot be reduced by medication. In this situation, your eye doctor will go over the best course of action for your therapy.
Surgery
Because the dangers associated with these treatments are greater than the real risk of developing glaucomatous damage from ocular hypertension, laser and surgical therapy are not typically utilized to treat ocular hypertension. However, if you cannot tolerate your eye medications, laser surgery could be an option, and you should discuss this therapy with your eye doctor.
Next Steps
People with ocular hypertension may need to see a doctor every two months to yearly, or even sooner if the pressures are not being sufficiently controlled, depending on the degree of optic nerve damage and the level of intraocular pressure control.
People with elevated intraocular pressure, normal-appearing optic nerves, and normal results from visual field testing should nonetheless be concerned about glaucoma, as should those with normal intraocular pressure, suspicious-appearing optic neurons, and abnormal results from visual field testing. These persons need to be continuously monitored because their risk of developing glaucoma is higher.
Prevention
Although ocular hypertension cannot be prevented, glaucoma can be avoided by having frequent eye exams with an eye doctor.
Outlook
For those who suffer from ocular hypertension, the outlook is excellent.
Most persons with ocular hypertension do not develop primary open-angle glaucoma and maintain their good vision throughout their lifetimes with appropriate follow-up care and adherence to medical treatment.
Poor management of high intraocular pressure can result in ongoing alterations to the optic nerve and visual field that may eventually cause glaucoma.
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