This month we will cover the diagnosis of a glaucoma suspect. This is not considered to be glaucoma but can be a risk a factor for it.
What does it mean to be a glaucoma suspect?
A glaucoma suspect is an individual whose exam shows a finding that is suspicious or suggestive of glaucoma. It does not mean that the patient has glaucoma. This suspicion is caused by: the appearance of the optic nerve, an abnormal visual field exam, or a high eye pressure, also referred to as ocular hypertension. Ocular hypertension will be our focus next month.
What are the symptoms?
A glaucoma suspect has no glaucoma damage and no ocular symptoms.
How is it detected?
A comprehensive exam including checking the vision and the pressure are important to determine if someone is a glaucoma suspect. A dilated eye exam is imperative to see the optic nerve. The exam and testing are essentially the same as if someone has open angle glaucoma.
Photos are taken to monitor for any changes over time. This allows doctors to determine if the optic nerve is changing in its appearance. This photo shows what a normal optic nerve looks like. The arrow points to the pale circle in the middle which is small in size.
The following photo shows an optic nerve that is considered to be suspicious for glaucoma. The pale circle in the center is much larger than the normal nerve. The arrows point to the edge of the pale circle.
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 is a glaucoma suspect, 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. The nerve thickness is normal and is plotted in the green area.
The following photo is of an optic nerve that looked suspicious for glaucoma on exam. However, there is no damage to the nerve, and the nerve thickness is normal and follows 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 a suspicious looking optic nerve 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.
The next photo shows some changes in the visual field. The arrows point to the area where the patient did not see. However, this patient is considered a glaucoma suspect because there is no damage to the optic nerve.
Are there any treatments for glaucoma suspect patients?
Usually there is no treatment if the changes on exam are based on the nerve or visual field. 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. It is possible for this to progress to actual glaucoma. By doing testing at least once a year, doctors will be able to assess if anything has worsened and requires treatment.
Return next month for our final installment on glaucoma!
- Image courtesy of Nisha Gupta, MD [return]