Optical Coherence Tomography in Patients with Chiari I Malformation

Abstract

Background/Aims. To evaluate optic nerve head with spectral domain optical coherence tomography (OCT) in patients with Chiari I malformation (CMI) compared to healthy controls. Methods. Cross-sectional study. OCT of the optic nerve head of 22 patients with CMI and 22 healthy controls was quantitatively analyzed. The healthy controls were matched for age and sex with the study population. Mean retinal nerve fiber layer (RNFL) thickness was calculated for both eyes; the mean thickness value was also registered for each quadrant and for each subfield of the four quadrants. Results. CMI patients showed a reduction of the RNFL thickness in both eyes. This reduction was more statistically significant (P < 0.05) for the inferior quadrant in the right eye and in each quadrant than nasal one in the left eye. Conclusion. A distress of the retinal nerve fibers could explain the observed reduction of the RNFL thickness in patients with CMI; in our series the reduction of the RNFL thickness seems lower when CMI is associated with syringomyelia.

Neuro-ophthalmology of type 1 Chiari malformation

“…Type 1 Chiari malformation typically affects ocular motility, but the rare involvement of afferent visual system is also possible [42-44]. A structural abnormality in the posterior fossa in subjects with type 1 Chiari malformation can lead to malignant increases in cerebrospinal fluid pressure.…”

“…Such deficit can present with acute onset of visual loss and malignant papilledema, requiring emergent cerebrospinal fluid shunt procedures for visual recovery [43,45,46]. Chronic type 1 Chiari malformation patients can present with thinning of the retinal nerve fiber layer although evidence for such thinning is not robust using conventional quantitative techniques such as ocular coherence tomography [44]. …”

Chiari 1 malformation with optic disc drusen

“…18 OCT is an important tool in patients with CM1 both for the differential diagnosis of papilledema and pseudopapilledema and for the screening of the probable retinal nerve fiber layer thickness changes. 19 The CSF flow has been demonstrated as abnormal in patients with CM.1 [1][2][3] Patients with CM1 has diminished anterior-posterior diameter of the CSF space at the FM, decreased CSF flow rates at the FM, and increased cervical CSF and pulse pressures. This altered CSF flow may lead to an increase in ICP by mechanical obstruction of outflow at the FM region.…”

Chiari I malformation presenting with ganglion cell complex thinning on routine examination

“…Figus et al (5) evaluated OCT images of the optic nerve head in patients with CMI and measured the mean peripapillary RNFL thickness. They found decreased RNFL Arq Bras Oftalmol.…”