Ocular hypertension is a term used to indicate that the intraocular pressure, or pressure of fluid inside the eye, is higher than normal. Normal readings generally consist of pressures measuring 10 to 21 millimeters of mercury, or mm Hg. Readings over 21, however, suggest an underlying problem causing the ocular hypertension. These high readings require prompt attention in order to properly diagnose and treat the condition.
How Intraocular Pressure is Measured
Intraocular pressure is measured by a special optical testing procedure known as tonometry. This procedure is typically performed manually, requiring topical anesthetic, as contact with the eye’s tear film is required. A non-evasive method, often referred to as “puffing” or “the puff test” is performed by a machine, although readings taken via this method tend to run higher than that of manual tonometry.
Causes of Ocular Hypertension
Glaucoma is one of the most common and frightening causes of ocular hypertension. This disease is not only a leading cause of ocular hypertension, but high pressures without underlying conditions can actually lead to damage of the optic nerve and the development of glaucoma later in life. This situation is often referred to as pre-glaucoma or at-risk glaucoma.
Certain medications have been linked with ocular hypertension. Steroidal medications commonly used to treat asthma have been linked to this condition, as well as steroidal eye drops designed for use after refractive surgeries, such as the popular LASIK procedure.
Excessive fluid production within the eye is known to increase intraocular pressure. Aqueous fluid is produced in a part of the eye known as the ciliary body, located just behind the iris. This fluid is drained regularly through the intricate trabecular meshwork. If too much fluid is produced, the drainage rate falls quite short, causing an increase in the pressure within the eye.
Slow or impaired drainage of the aqueous fluid can lead to all sorts of issues in the production of aqueous fluid, causing intraocular pressure to rise dramatically.
Various eye injuries affecting the delicate balance of both aqueous production and drainage can cause increased pressure readings. Past injuries, even those reaching back several years, can suddenly lead to ocular hypertension.
Diagnosing Ocular Hypertension
Ocular hypertension in itself is not a disease, but rather a symptom indicating an underlying condition. In order for the cause of ocular hypertension to be properly diagnosed, it is necessary to undergo a thorough examination of the eye, performed by a qualified optometrist or ophthalmologist. During this exam, the doctor will likely dilate the pupil, in order to obtain the widest view of the optic nerve and retina. If damage to either of these structures is noted, further treatment followed by regular examinations may be required.