Ophthalmologists and optometrists can detect inflammation of the optic nerve (also called optic neuritis) by assessing the severity of the signs and symptoms shown through different tests.
This happens as part of a routine eye exam, where your optometrist will perform a series of tests, some of which check the function of the optic nerve, such as checking your visual field (sometimes called peripheral vision) and how your pupil responds to light.
If they suspect optic neuritis, they may want to get a clearer view of some of the internal structures of your eye using an OCT (optical coherence tomography) scan. Below, we’ll take a look at how OCT can help detect and manage optic nerve inflammation.
Can an OCT scan help detect optic neuritis?
Alongside thorough, targeted eye examinations, optometrists are increasingly using OCT to help detect optic neuritis.
Optic neuritis can cause changes to the thickness of the layers of the eye, particularly in the retina and the tissues of the optic nerve itself. The retina is the innermost, light-sensitive membrane in the eye and consists of several layers.
The optic nerve carries electrical impulses from the eye to the brain, which are then processed to give us vision. Each nerve contains around a million fibres that receive information from the rods and cones of the retina. Damage to these delicate structures can, in some cases, cause loss of vision.
An OCT scan creates a composite image of the various layers of the optic nerve and retina to allow us to measure their thickness, including the thickness of the retinal nerve fibre layer (RNFL). OCT also provides direct visualisation of the optic nerve. Optometrists can then make informed decisions about suspected optic neuritis, based on the thickness of these layers and the appearance of the optic nerve, as well as their findings from your eye test.
How does OCT help manage and treat optic neuritis?
Not only is OCT useful in detecting optic neuritis alongside a thorough eye test, but it also plays an important role in managing the condition and monitoring the treatment process. Measurements of the thicknesses of various layers of the eye can be repeated over time and the changes documented.
Keeping track of the thickness of these layers helps your eyecare professional, usually an ophthalmologist, to assess the progression of your condition and how well you respond to treatment. If they need to, they can then make changes to your management plan.
Can optic neuritis be misdiagnosed?
Several eye conditions such as anterior ischemic optic neuropathy (AION) and Leber’s hereditary optic neuropathy (LHON), have similar characteristics to optic neuritis, although their treatment is very different.2 It’s therefore important for optometrists to get a clear assessment of the eye in order to diagnose optic neuritis correctly, and to prescribe the right treatment.
Latest technologies and new imaging tools such as OCT scanning can help reduce the risk of misdiagnosis. OCT allows the optometrist to see detailed images of the eye and pick up the specific features associated with each of these conditions. The presence or absence of characteristic signs on OCT can help differentiate between eye conditions that closely mimic optic neuritis.
What is the link between optic neuritis and MS?
Optic neuritis is a common initial symptom of multiple sclerosis (MS), a debilitating disease that affects the central nervous system.1 When someone is diagnosed with optic neuritis, doctors always consider the possibility of progression to multiple sclerosis. It’s important to note, however, that not everyone who experiences optic neuritis develops MS.
How can OCT help?
Optical coherence tomography (OCT) is a safe, easy, and non-invasive technique that can help with the early detection of optic neuritis, alongside a thorough eye examination. Optic neuritis almost always requires further testing and evaluation via referral from your optometrist in order to understand the cause of the inflammation.
For this reason, it’s important to get regular eye tests every two years. Routine eye tests allow the optometrist to spot any potential signs of optic neuritis early on and ensure treatment is started as soon as possible.
1. Kale N. Optic neuritis as an early sign of multiple sclerosis. Eye Brain. 2016;8:195–202. Published 2016 Oct 26. [Online]. Available at: https://www.ncbi.nlm.nih.gov/p... [Accessed 18 February 2020].
2. Hoorbakht H, Bagherkashi F. Optic neuritis, its differential diagnosis and management. Open Ophthalmol J. 2012;6:65–72. [Online]. Available at: https://www.ncbi.nlm.nih.gov/p... [Accessed 18 February 2020].