Relationship between optical coherence tomography and electrophysiology of the visual pathway in non-optic neuritis eyes of multiple sclerosis patients

Retinal nerve fiber layer changes after transsphenoidal and transcranial pituitary adenoma resection

PURPOSE

Retinal nerve fiber layer (RNFL) will show retrograde degeneration following damage to the optic nerve or the optic tract in patients with pituitary adenoma. RNFL changes after surgery have not been studied thoroughly in patients with the transsphenoidal surgery and patients with the transcranial surgery.

METHODS

Thirty-seven patients with pituitary adenoma were recruited from Huashan hospital between September 2010 and July 2014. Patients were divided into two groups: the transsphenoidal group and the transcranial group. Before surgery, 3 and 9 months after surgery, follow-up optic coherence tomography were conducted.

RESULTS

Twenty-one patients underwent transsphenoidal surgery and 16 patients underwent transcranial surgery. No obvious difference were observed between these two groups before surgery. The mean RNFL thickness did not change significantly in patients who underwent transsphenoidal surgery: 91.1 before surgery, 92.7 at 3 months after surgery (p = 0.392) and 92.8 at 9 months after surgery( p = 0.395). The mean RNFL thickness decreased inpatients who underwent transcranial surgery: 93.6 before surgery, 86.1 at 3 months after surgery (p = 0.000) and 88.1 at 9 months after surgery (p = 0.005).

CONCLUSIONS

In the short time follow-up, there was no change of RNFL thickness in pituitary adenoma patients underwent transsphenoidal surgery, but a decrease inpatients underwent transcranial surgery.

How strong is the relationship between glaucoma, the retinal nerve fibre layer, and neurodegenerative diseases such as Alzheimer's disease and multiple sclerosis?

Glaucoma is a neurodegenerative disorder with established relationships with ocular structures such as the retinal nerve fibre layer (RNFL) and the ganglion cell layer (GCL). Ocular imaging techniques such as optical coherence tomography (OCT) allow for quantitative measurement of these structures. OCT has been used in the monitoring of glaucoma, as well as investigating other neurodegenerative conditions such as Alzheimer's disease (AD) and multiple sclerosis (MS). In this review, we highlight the association between these disorders and ocular structures (RNFL and GCL), examining their usefulness as biomarkers of neurodegeneration. The average RNFL thickness loss in patients with AD is 11 μm, and 7 μm in MS patients. Most of the studies investigating these changes are cross-sectional. Further longitudinal studies are required to assess sensitivity and specificity of these potential ocular biomarkers to neurodegenerative disease progression.

Analysis of retinal nerve fibre layer, visual evoked potentials and relative afferent pupillary defect in multiple sclerosis patients

OBJECTIVE

The aim of this study was to analyse retinal nerve fibre layer (RNFL), pattern-reversal visual evoked potentials (pVEPs) and relative afferent pupillary defect (RAPD) changes in multiple sclerosis (MS) patients with the consideration of past optic neuritis (ON).

METHODS

Ophthalmological, neurological, OCT, RNFL and pVEP studies were conducted in 59 MS patients. RAPD tests were performed in 47 of them. Control group consisted of 28 healthy volunteers.

RESULTS

Abnormal RNFL was found in 59% of cases of eyes with ON and 28% of eyes without ON. In eyes with ON, significantly lower RNFL values were indicated in the temporal and lower quadrants. Elongation of pVEP latency was found in 83% of eyes with ON and 60% of eyes without ON. The average value of pVEP latency was larger and the amplitude was lower in the subgroup of eyes with RNFL at the borderline or below the norm. RAPD was observed only in eyes with ON and with RNFL thinning. No association was found between the RAPD and pVEP parameters.

CONCLUSIONS

VEPs were more frequently abnormal than RNFL in MS patients. RNFL damage in eyes without ON may indicate neurodegenerations in CNS of MS patients; it can also be the consequence of subclinical ON.

SIGNIFICANCE

An analysis of RNFL and VEP can be useful for evaluating the optic nerve in MS patients.

Benign Multiple Sclerosis is Associated with Reduced Thinning of the Retinal Nerve Fiber and Ganglion Cell Layers in Non-Optic-Neuritis Eyes

Background and Purpose

It is exceedingly difficult to differentiate benign multiple sclerosis (BMS) from relapsing-remitting multiple sclerosis (RRMS) based on clinical characteristics, neuroimaging, and cerebrospinal fluid tests. Optical coherence tomography (OCT) allows quantification of retinal structures, such as the retinal nerve fiber layer (RNFL) thickness, at the optic disc and the ganglion cell layer (GCL) at the macula, on a micrometer scale. It can also be used to trace minor alterations and the progression of neurodegeneration, help predict BMS, and influence the choice of therapy. To utilize OCT to detect the extent of changes of the optic disk and macular microstructure in patients with BMS and RRMS compared to healthy controls (HCs), with special focus on changes related to the presence/absence of optic neuritis (ON).

Methods

Spectral-domain OCT was applied to examine eyes from 36 patients with multiple sclerosis (MS), comprising 11 with BMS and 25 with RRMS, and 34 HCs.

Results

The RNFL and GCL were significantly thinner in eyes previously affected by ON, irrespective of the type of MS (i.e., BMS or RRMS), than in HCs. Significant thinning of the GCL was also observed in non-ON RRMS (and not non-ON BMS) compared to HCs. Correspondingly, a significant association between disease duration and thinning rates of the RNFL and GCL was observed only in non-ON RRMS (-0.54±0.24 and -0.43±0.21 µm/year, mean±SE; p<0.05 for both), and not in non-ON BMS (-0.11±0.27 and -0.24±0.24 µm/year).

Conclusions

The RNFL and GCL were thinner in both ON- and non-ON MS, but the change was more pronounced in ON MS, irrespective of the MS subtype studied herein. GCL thinning and the thinning rate of both the GCL and RNFL were less pronounced in non-ON BMS than in non-ON RRMS. These findings may help to predict the course of BMS.