This month we will cover the diagnosis of ocular hypertension. This is not considered to be glaucoma but can be a risk a factor for it.
What does ocular hypertension mean?
Ocular hypertension is the term used when the eye pressure is high. The eye produces a fluid called aqueous humor that supplies the eye with nutrients. This fluid contributes to the eye pressure. If it cannot drain properly, the eye pressure goes up. A person with ocular hypertension is considered a glaucoma suspect and it is a risk factor for developing glaucoma.
What are the symptoms?
Usually someone with ocular hypertension has no ocular symptoms.
How is it detected?
A comprehensive exam including checking the vision and the pressure are important to determine if someone has ocular hypertension. A dilated eye exam is imperative to see the optic nerve to ensure there is no damage to the nerve. The exam and testing are essentially the same as if someone has open angle glaucoma.
The exam in a person with ocular hypertension should be normal. Photos are taken to monitor for any changes over time and potential progression to glaucoma. This photo shows a normal optic nerve in a person with ocular hypertension. The arrow points to the pale circle in the middle which is small in size.
In addition to monitoring the nerve on exam, doctors take a photo of the nerve to look deeper at the fibers that make up the nerve. As one gets older, it is normal to lose some of these fibers. With glaucoma, the fibers are damaged and lost more quickly. However, in someone who only has ocular hypertension, there is no damage to the fibers and this photo should look normal. Optical coherence tomography (OCT) shows if the nerve has any damage due to loss of nerve fibers. It shows the thickness of the retinal nerve fiber layer (RNFL).
This photo displays a healthy optic nerve in a person with ocular hypertension. The nerve thickness is normal and is plotted in the green area.
Finally, doctors conduct a test to check the peripheral vision of patients to look for damage from glaucoma. When the optic nerve is damaged, the vision loss starts in the periphery and a formal visual field test is done to check this vision.
The following is a visual field of someone with ocular hypertension but no damage to the nerve and no vision changes on the visual field. It is a normal visual field exam. The arrow points to the normal blind spot.
Does ocular hypertension require treatment?
If the pressure is not very high, the doctor may not decide to treat right away. If the pressure is high or one is at higher risk for developing glaucoma, the doctor may decide to treat with eye drops or laser.
There are several types of drops that work in different ways to lower the eye pressure. The doctor may decide to use one drop or a combination of several drops to lower the eye pressure. The laser procedure is another way to decrease the pressure. It creates small holes in the area of the eye where fluid flows. The holes make it easier for fluid to flow properly and help to lower the eye pressure.
If the eye pressure is very high and not controlled with these treatments, the doctor may decide that surgery is the best option to decrease the pressure.
Treatment will be based on your exam and discussion with your doctor. It reduces the risk of developing glaucoma but does not eliminate it. The ultimate goal for treatment is to prevent any damage to the optic nerve and vision loss.
An eye exam and the tests described above should be done at least once a year to ensure that there are no changes. It is very important for a patient to maintain follow up care so that the doctor is able to assess if anything on exam has worsened or progressed to glaucoma.
Return next month for a discussion on a new topic!
- Image courtesy of Nisha Gupta, MD [return]