Obligatory medical device diagnostics.
- Eye examination
- Slit-lamp examination (slit-lamp microscope; viewing of the eyeball under appropriate illumination and high magnification; in this case: Viewing of the anterior and middle sections of the eye).
- Ophthalmoscopy (ophthalmoscopy; examination of the central fundus) – to diagnose optic neuritis [paille usually appears sharp; may be mild papilledema (one-third of patients)).
- Visual acuity determination (visual acuity determination) [for optic neuritis from “no light appearance” to 1.5; in two-thirds of MS patients < 0.5; normal findings: 20-year-olds: 1.0-1.6, 80-year-olds: 0.6-1.0]
- Relative afferent pupillary defect (RAPD) testing: see below Physical examination/swinging-flashlight test (SWIFT; pupil alternating exposure test; pupil comparison test).
- Perimetry (visual field measurement)
- Magnetic resonance imaging of the skull (cranial MRI; cranial MRI; cMRI) as the gold standard – for suspected optic neuritis; multiple sclerosis; signs of MS on MRI include:
- Contrast uptake in T1 sequences (DD: optic sheath meningioma may give the same finding as optic neuritis; if contrast uptake persists after 3 months, think optic sheath meningioma; if contrast uptake of more than in half of optic nerve and involvement of optic chiasm, think: Neuromyelitis optica)
- In the case of two and more demyelinating foci in the brain (especially in the bar and periventricular medullary bed), at least one of which takes up contrast medium (gadolinium) = multiple sclerosis
- With two and more demyelinating foci in the brain that do not take up contrast = “clinically isolated syndrome” (HIS; associated with a high risk of MS)
- When there are no typical lesions of multiple sclerosis: 24% of patients after optic neuritis develop multiple sclerosis
Note: Optic neuritis should not be followed by cranial CT instead of cranial MRI.
Optional medical device diagnostics – depending on the results of the history, physical examination and mandatory laboratory parameters – for differential diagnosis.
- Optical coherence tomography (OCT; imaging technique for examination of the retina, vitreous, and optic nerve; method for producing optical, two-dimensional cross-sectional images) – for diagnosis and follow-up [peripapillary retinal nerve fiber layer thickness reflects severity].
- Visual evoked potentials (VEP; electrical voltage changes derived from an electroencephalogram (EEG) over the primary visual cortex while the patient is exposed to visual stimuli) [VEP are latency delayed in optic neuritis]
- Perimetry (visual field measurement)
- In atypical optic neuritis: Exclusion of sarcoidosis and tuberculosis (for diagnosis see under the diseases of the same name).