Baseline retinal nerve fiber layer thickness and macular volume quantified by OCT in the North American phase 3 fingolimod trial for relapsing-remitting multiple sclerosis

Optical Coherence Tomography Angiography: Revolutionizing Clinical Diagnostics and Treatment in Central Nervous System Disease

Optical coherence tomography angiography (OCTA), as a new generation of non-invasive and efficient fundus imaging technology, can provide non-invasive assessment of vascular lesions in the retina and choroid. In terms of anatomy and development, the retina is referred to as an extension of the central nervous system (CNS). CNS diseases are closely related to changes in fundus structure and blood vessels, and direct visualization of fundus structure and blood vessels provides an effective "window" for CNS research. This has important practical significance for identifying the characteristic changes of various CNS diseases on OCTA in the future, and plays a key role in promoting early screening, diagnosis, and monitoring of disease progression in CNS diseases. This article reviews relevant fundus studies by comparing and summarizing the unique advantages and existing limitations of OCTA in various CNS disease patients, in order to demonstrate the clinical significance of OCTA in the diagnosis and treatment of CNS diseases.

Baseline retinal nerve fiber layer thickness as a predictor of multiple sclerosis progression: New insights from the FREEDOMS II study

BACKGROUND AND PURPOSE

The aim was to evaluate the potential of retinal nerve fiber layer thickness (RNFLT) measured with optical coherence tomography in predicting disease progression in relapsing-remitting multiple sclerosis (RRMS).

METHODS

Analyses were conducted post hoc of this 24-month, phase III, double-blind study, in which RRMS patients were randomized (1:1:1) to once daily oral fingolimod 0.5 mg, 1.25 mg or placebo. The key outcomes were the association between baseline RNFLT and baseline clinical characteristics and clinical/imaging outcomes up to 24 months. Change of RNFLT with fingolimod versus placebo within 24 months and time to retinal nerve fiber layer (RNFL) thinning were evaluated.

RESULTS

Altogether 885 patients were included. At baseline, lower RNFLT was correlated with higher Expanded Disability Status Scale score (r = -1.085, p = 0.018), lower brain volume (r = 0.025, p = 0.006) and deep gray matter volume (r = 0.731, p < 0.0001), worse visual acuity (r = -19.846, p < 0.0001) and longer duration since diagnosis (r = -0.258, p = 0.018). At month 12, low baseline RNFLT (<86 μm) versus high baseline RNFLT (≥99 μm) was associated with a greater brain volume loss (percentage change -0.605% vs. -0.315%, p = 0.035) in patients without optic neuritis history. At month 24, low baseline RNFLT versus high baseline RNFLT was associated with a higher number of new or newly enlarged T2 lesions (mean number 4.0 vs. 2.8, p = 0.014) and a higher risk of subsequent RNFL thinning (hazard ratio 2.55; 95% confidence interval 1.84-3.53; p < 0.001). The atrophy of the RNFL in the inferior quadrant was alleviated with fingolimod 0.5 mg versus placebo at month 24 (Δ(least squares mean) = 1.8, p = 0.047).

CONCLUSION

Retinal nerve fiber layer thickness could predict disease progression in RRMS.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT00355134, https://clinicaltrials.gov/ct2/show/NCT00355134.

Evaluation of optical coherence tomography angiography findings in patients with multiple sclerosis

Purpose:

To evaluate optical coherence tomography angiography findings in patients with multiple sclerosis (MS).

Methods:

This prospective noninterventional study was conducted on 30 eyes of relapsing-remitting MS patients. Group (1) included 10 eyes with a history of optic neuritis (ON), group (2) included 10 eyes without any history of optic neuritis (MS-ON), and group (3) included 10 eyes of normal age/sex/refraction matched participants. Optical coherence tomography (OCT) and OCT-A (ZEISS Cirrus™ HD-OCT Model 4000 (Carl Zeiss-Meditec, Dublin, CA) of the optic disc were done for all patients.

Results:

The best-corrected visual acuity was diminished in MS cases, especially in patients with ON with P value <0.001. The retinal nerve fiber layer (RNFL) thickness showed a significant decrease in the average thickness and in all quadrants, notably the temporal quadrant in group 1 (P < 0.001). Ganglion cell layer thickness was diminished in average thickness and in all quadrants in both groups of MS, but only the first group showed statistical significance with P value <0.001). In respect to optic disc perfusion, Average, superficial, and deep vascular density index (AVDI, VDI 1, VDI 2) were statistically significantly lower in groups 1, 2 with (P-value < 0.001).

Conclusion:

Decreased vascular perfusion of the optic nerve in MS patients, especially in those with ON is strongly correlated with the damage of RNFL and ganglion cell layer detected by OCT.

Evaluation of the effect of fingolimod (FTY720) on macular perfusion by swept-source optical coherence tomography angiography in patients with multiple sclerosis

AIM

To determine changes in retinal microcirculation, caused by fingolimod (FTY720) use, via swept-source optical coherence tomography angiography (SS-OCTA) in relapsing-remitting multiple sclerosis (RR-MS) patients.

MATERIALS AND METHODS

80 patients with RR-MS, who were using fingolimod, and 50 healthy control subjects were included in the study. Group 1 consisted of 40 eyes from 40 RR-MS patients, who had been using fingolimod for less than six months, and Group 2 consisted of 40 eyes from 40 RR-MS patients, who had been using fingolimod for longer than six months. All participants underwent SS-OCTA via DRI OCT Triton (Topcon, Tokyo, Japan), analysing their central macular thickness (CMT) (µm), subfoveal choroidal thickness (SFCT) (µm), superficial (VDs) (%) and deep vascular plexuses (VDd) (%), choriocapillaris (VDcc) (%), and superficial and deep foveal avascular zones (FAZs, FAZd, respectively) (%) in mean values.

RESULTS

The mean follow-up times for patients in Groups 1 and 2 were 2.9 ± 1.5 months and 22.5 ± 11.3 months, respectively. The FAZs value in Group 2 was found to be significantly higher than that in both Group 1 and the control group (p = 0.034, p = 0.042, respectively). The VDs central value in Group 2 did not differ significantly from that in Group 1 or the control group (p > 0.05), while the VDs central value was higher in Group 1 than in the control group (p = 0.008). In Group 1, the VDd central value was significantly higher than in Group 2 and the control group (p = 0.047; p = 0.020, respectively). The CMT measurement for Group 2 was significantly lower than in Group 1 and the control group (p = 0.008, p = 0.003, respectively).

CONCLUSION

Fingolimod use seems to remarkably increase VDs and VDd measurements in the early period of administration and decrease CMT over a longer period of administration in patients with RR-MS.

Evaluating optic nerve diameter as a possible biomarker for disability in patients with multiple sclerosis

BACKGROUND AND PURPOSE

The development of new biomarkers for multiple sclerosis (MS) is of paramount importance to improve our ability to predict disease progression and disability. The aim of this study was to evaluate the potential role of the optic nerve diameter (OND) measured by ultrasonography as a biomarker of early disability in patients with relapsing-remitting multiple sclerosis (RRMS).

METHODS

Forty-nine RRMS patients, 23 with a history of optic neuritis (MS-ON) and 26 without a history of optic neuritis (MS N-ON), and 50 age- and sex-matched healthy control subjects were included in the study. The OND and optic nerve sheath diameter (ONSD) were measured by transorbital sonography (TOS), and the retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) thicknesses were measured by optical coherence tomography (OCT) using the Optovue RTVue™ system (Optovue, Inc., Fremont, CA, USA).

RESULTS

There was no significant difference between the patient (whether ON or N-ON eyes) and control groups in either the OND (p=0.979) or the ONSD (p=0.911). However, patients with an expanded disability status scale (EDSS) score >2 had a significantly lower OND and RNFL thicknesses (p=0.014, p=0.010 respectively) than patients with an EDSS score ≤2. Statistical logistic regression revealed that OND was an independent predictor of EDSS>2 (p=0.044, OR =0.000, 95% CI=0.000-0.589).

CONCLUSION

The OND, as measured by ultrasonography, could be potentially used as a biomarker for the detection of early disability in RRMS patients.

Retinal Nerve Fiber Layer Thickness in Children: The Gobi Desert Children Eye Study

Purpose

Because there is a paucity of population-based data on retinal nerve fiber layer thickness (RNFLT) for children, we measured the RNFLT and its associations in schoolchildren.

Methods

The population-based Gobi Desert Children Eye Study included all schoolchildren aged 6 to 21 years living in Ejina, Inner Mongolia. The children underwent a comprehensive ocular examination with cycloplegic refractometry and spectral-domain optical coherence tomography of the optic nerve head. The peripapillary RNFLT was measured on the optical coherence tomography images of a circular scan with a diameter of 3.4 mm.

Results

Out of 1565 participants, RNFLT data were available for 1440 (92.5%) children. The mean global RNFLT was 101.3 ± 9.2 μm in right eyes. The RNFLT was thickest in the temporal inferior sector (157.3 μm), followed by the temporal superior sector (143.8 μm), the nasal inferior sector (109.7 μm), the nasal superior sector (106.9 μm), temporal sector (85.2 μm), and the nasal sector (61.7 μm). In multivariate analysis, the RNFLT decreased with higher myopic refractive error (P < 0.001), male sex (P = 0.001), higher intraocular pressure (P = 0.002), and lower birth weight (P = 0.03). It was not significantly associated with age (P = 0.19), body mass index (P = 0.57), mean arterial blood pressure (P = 0.33), pulse rate (P = 0.28), and subfoveal choroidal thickness (P = 0.11).

Conclusions

The RNFLT in children showed a regional distribution, with the thickest part in the temporal inferior sector and the thinnest part located in the nasal sector. The overall RNLFT significantly decreased with higher myopic refractive error and male sex. In schoolchildren, in contrast to adults, the RNFLT did not decrease with older age. These findings may be considered when interpreting RNFLT data in children.

The role of optical coherence tomography in therapeutics and conditions, which primarily have systemic manifestations: a narrative review

Optical coherence tomography is designed to evaluate in vivo qualitative and quantitative changes of the anterior segment, optic nerve and the retina. Initial applications of this technology were confined mainly to ophthalmic diseases. However recently, numerous studies have evaluated its use in systemic conditions and in therapeutics where, optic nerve and retinal architecture can be assessed to monitor progression of systemic conditions and its response to treatment. This is a narrative review aimed at evaluating the debate surrounding the role of spectral domain optical coherence tomography, in systemic conditions where optic nerve affection can be measured and be used in the diagnosis, monitoring and assessment of treatment effect as a non-invasive, quick, novel technique.

Longitudinal optical coherence tomography study of optic atrophy in secondary progressive multiple sclerosis: Results from a clinical trial cohort

BACKGROUND

Limited prospective information exists regarding spectral-domain optical coherence tomography (SD-OCT) in secondary progressive multiple sclerosis (SPMS).

OBJECTIVE

Document cross-sectional and longitudinal retinal nerve fiber layer (RNFL) and macular ganglion cell plus inner plexiform layer (GCIPL) features of an SPMS clinical trial cohort.

METHODS

Prospective, observational study using a 2-year randomized placebo-controlled SPMS trial cohort with yearly SD-OCT testing. Post hoc analysis determined influences of optic neuritis (ON), disease duration, and baseline SD-OCT on annualized atrophy rates and on correlations between OCT and brain atrophy.

RESULTS

Mean RNFL and GCIPL values of patients ( n = 47, mean age = 59 years, mean disease duration = 30 years) were significantly lower among eyes with prior ON than those without (no history of ON (NON)). Annualized RNFL (-0.31 µm/year) and GCIPL (-0.29 µm/year) atrophy rates did not differ between ON and NON eyes. Baseline RNFL thickness >75 µm was associated with greater annualized RNFL atrophy (-0.85 µm/year). Neither RNFL nor GCIPL atrophy correlated with whole-brain atrophy.

CONCLUSION

This study suggests that eyes with and without ON history may be pooled for atrophy analysis in SPMS clinical trials using SD-OCT. Low baseline RNFL, small retinal atrophy rates, and lack of correlation with whole-brain atrophy in this population are important trial design considerations.

Acute hypertensive uveitis as the first presentation of multiple sclerosis

Ophthalmic manifestations of multiple sclerosis are frequent including acute optic neuritis, ocular motor disturbances and intermediate uveitis. We report an unusual case of multiple sclerosis presenting as acute hypertensive uveitis. A 56-year-old man was referred by his family doctor with a 2-week history of right eye pain and decreased vision. Best-corrected visual acuity was Count Fingers on the right and 6/9-2 on the left. Intraocular pressure was 55mmHg and 14 mmHg on the right and left respectively. He had a right relative pupillary defect and a left internuclear ophthalmoplegia. Vitreous cells were present in the right eye and there was peripheral sclerosis and periphlebitis superior temporally. MRI Brain and Spine revealed multiple T2 hyperintense lesions consistent with multiple sclerosis. Multiple sclerosis may present initially with an acute elevation of intraocular pressure and intermediate uveitis.

Visual Structure and Function in Collision Sport Athletes

BACKGROUND

Vision-based measures have been shown to be useful markers in multiple sclerosis (MS), Alzheimer and Parkinson disease. Therefore, these testing paradigms may have applications to populations explaining repetitive head trauma that has been associated with long-term neurodegenerative sequelae. We investigated retinal structure and visual function in professional collision sport athletes compared to age- and race-matched control participants.

METHODS

In this cross-sectional study, participants underwent spectral-domain optical coherence tomography (OCT) measurements of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC = ganglion cell + inner plexiform layers) thickness. High-contrast visual acuity (100% level), low-contrast letter acuity (LCLA) (1.25% and 2.5% levels), and King-Devick Test of rapid number naming performance were administered. Vision-specific quality of life (QOL) measures were assessed.

RESULTS

Among 46 collision sport athletes (boxing, n = 14; football, n = 29; ice hockey, n = 3) and 104 control participants, average RNFL thickness was a significant predictor of athlete vs control status with athletes demonstrating 4.8-μm of thinning compared to controls (P = 0.01, generalized estimating equation [GEE] models accounting for age and within-subject, intereye correlations). Athlete vs control status was not a predictor of RNFL thickness for the subgroup of football players in this cohort (P = 0.60). Binocular (P = 0.001) and monocular (P = 0.02) LCLA at 2.5% contrast and vision-specific QOL (P = 0.04) were significant predictors of athlete vs control status (GEE models accounting for age and within-subject, intereye correlations). Rapid number naming performance times were not significantly different between the control and athlete groups.

CONCLUSIONS

This study showed that retinal axonal and neuronal loss is present among collision sport athletes, with most notable differences seen in boxers. These findings are accompanied by reductions in visual function and QOL, similar to patterns observed in multiple sclerosis, Alzheimer and Parkinson diseases. Vision-based changes associated with head trauma exposure that have the potential to be detected in vivo represent a unique opportunity for further study to determine if these changes in collision sport athletes are predictive of future neurodegeneration.

Longitudinal quantitative assessment of macula during therapy with fingolimod in relapsing-remitting multiple sclerosis

PURPOSE

Fingolimod is the first oral drug approved for treatment of relapsing-remitting multiple sclerosis (RR-MS), and it has potential macular side effects. Despite the qualitative evidence of macular oedema under treatment, longitudinal quantitative assessment is lacking. To address this issue, we measured macular volume and central foveal thickness in a cohort of MS patients on fingolimod over 12 months of treatment.

METHODS

Central foveal thickness (CFT) and total macular volume (TMV) were longitudinally recorded with spectral-domain optical coherence tomography in a cohort of 23 RR-MS patients treated with fingolimod at baseline, 3, 6 and 12 months. OCT parameters were analysed considering previous history of optic neuritis (ON). Comparison of means was performed with variance analysis (ANOVA).

RESULTS

Macular oedema occurred in none of the patients. Comparing both groups of patients (with and without previous ON), no statistically significant difference was found during the follow-up both for CFT and TMV (p = 0.99 and p = 0.96, respectively) although a slight early but not significant TMV reduction was detected.

CONCLUSIONS

In our cohort, therapy with fingolimod did not cause any change in CFT and TMV in MS patients during a 12-month follow-up independent of previous ON.

Application of Optical Coherence Tomography in the Detection and Classification of Cognitive Decline

Aim

This review aims to critically analyze the current literature on the relationship of optical coherence tomography (OCT) measures to cognition and dementia.

Background

Optical coherence tomography, a noninvasive method of imaging neuroretinal layers, and OCT angiography, a highly precise method of examining retinal vasculature, have widely been used to aid in the diagnosis and monitoring of a variety of ocular diseases. There is now an increasing body of evidence relating the structural and microvascular changes of the retina to cognitive impairment.

Review results

In general, several studies have found decreased retinal nerve fiber layer (RNFL) thickness in Alzheimer’s disease (AD) and mild cognitive impairment (MCI) and an association between RNFL thickness and continuous measures of cognitive ability, though findings were inconsistent across studies. In many studies, associations were found for specific regions of the RNFL but not with overall thickness. Studies linking OCT measures to non-Alzheimer’s dementia were lacking, and limited work has been done on persons with past cognitive decline but who remain cognitively normal (the ideal stage at which to target treatment). Common limitations of prior studies include a failure to account for intraocular pressure (IOP) and axial length.

Conclusion

Current research suggests a potential association between retinal findings observed on OCT and cognitive impairment. Methodologically robust research accounting for important covariates and looking at changes in OCT and/ or cognition is needed to better characterize the association between OCT and cognitive ability.

Clinical significance

Further research is warranted to determine whether OCT findings can help identify the etiology of cognitive decline and/or serve as objective markers of AD. If this is the case, OCT may also help identify the presence of disease processes in cognitively normal individuals.

How to cite this article: Lee MJ, Abraham AG, Swenor BK, Sharrett AR, Ramulu PY. Application of Optical Coherence Tomography in the Detection and Classification of Cognitive Decline. J Curr Glaucoma Pract 2018;12(1):10-18.

Sex differences and subclinical retinal injury in pediatric-onset MS

Objective:

To assess retinal ganglion cell (RGC) injury and sex differences in axon loss in pediatric multiple sclerosis (MS).

Methods:

This is a cross-sectional evaluation of consecutive pediatric MS subjects and controls. Eyes with acute optic neuritis (ON) within 6 months of visit were excluded. Spectral domain optical coherence tomography (OCT) included peripapillary ring and macular scans with post-acquisition segmentation of retinal layers using automated software (Heidelberg v1.8.6.0). Generalized estimating equations (GEEs) measured associations of sex, history of ON, disease duration, and age with OCT outcomes.

Results:

In all, 53 MS subjects (100 eyes, median disease duration = 1.0 years, interquartile range (IQR) = 0.3, 2.5) were compared to 19 control subjects (38 eyes). Eyes with history of ON showed reduced retinal nerve fiber layer (RNFL: −26.8 µm, 95% confidence interval (CI) = −38.9, −14.8, p < 0.001) and 26% lower ganglion cell layer (GCL) volumes (−0.12 mm3, 95% CI = −0.16, −0.072, p < 0.001) compared to control eyes. Non-ON MS eyes had lower temporal RNFL (−11.9 µm, 95% CI = −18.6, −5.3, p < 0.001) and GCL volumes (−0.036 mm3, 95% CI = −0.06, −0.011, p = 0.004) than control eyes. In MS eyes, males versus females had lower global RNFL (−9.4 µm, 95% CI = −17.4, −1.33, p = 0.022) and in ON eyes had lower temporal quadrant RNFL (−9.6 µm, 95% CI = −15.1, −4.15, p = 0.001).

Conclusion:

Subclinical retinal injury occurs in pediatric-onset MS patients without a history of ON. As in adult-onset MS, substantial GCL thinning is present in eyes with prior ON. Finally, greater retinal axonal injury occurs in boys compared to girls.

Fingolimod for relapsing-remitting multiple sclerosis

BACKGROUND

Fingolimod was approved in 2010 for the treatment of patients with the relapsing-remitting (RR) form of multiple sclerosis (MS). It was designed to reduce the frequency of exacerbations and to delay disability worsening. Issues on its safety and efficacy, mainly as compared to other disease modifying drugs (DMDs), have been raised.

OBJECTIVES

To assess the safety and benefit of fingolimod versus placebo, or other disease-modifying drugs (DMDs), in reducing disease activity in people with relapsing-remitting multiple sclerosis (RRMS).

SEARCH METHODS

We searched the Cochrane Multiple Sclerosis and Rare Diseases of the Central Nervous System (CNS) Group's Specialised Trials Register and US Food and Drug Administration reports (15 February 2016).

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing the beneficial and harmful effects of fingolimod versus placebo or other approved DMDs in people with RRMS.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane.

MAIN RESULTS

Six RCTs met our selection criteria. The overall population included 5152 participants; 1621 controls and 3531 treated with fingolimod at different doses; 2061 with 0.5 mg, 1376 with 1.25 mg, and 94 with 5.0 mg daily. Among the controls, 923 participants were treated with placebo and 698 with others DMDs. The treatment duration was six months in three, 12 months in one, and 24 months in two trials. One study was at high risk of bias for blinding, three studies were at high risk of bias for incomplete outcome reporting, and four studies were at high risk of bias for other reasons (co-authors were affiliated with the pharmaceutical company). We retrieved 10 ongoing trials; four of them have been completed.Comparing fingolimod administered at the approved dose of 0.5 mg to placebo, we found that the drug at 24 months increased the probability of being relapse-free (risk ratio (RR) 1.44, 95% confidence interval (CI) (1.28 to 1.63); moderate quality of evidence), but it might lead to little or no difference in preventing disability progression (RR 1.07, 95% CI 1.02 to 1.11; primary clinical endpoints; low quality evidence). Benefit was observed for other measures of inflammatory disease activity including clinical (annualised relapse rate): rate ratio 0.50, 95% CI 0.40 to 0.62; moderate quality evidence; and magnetic resonance imaging (MRI) activity (gadolinium-enhancing lesions): RR of being free from (MRI) gadolinium-enhancing lesions: 1.36, 95% CI 1.27 to 1.45; low quality evidence.The mean change of MRI T2-weighted lesion load favoured fingolimod at 12 and 24 months.No significant increased risk of discontinuation due to adverse events was observed for fingolimod 0.5 mg compared to placebo at six and 24 months. The risk of fingolimod discontinuation was significantly higher compared to placebo for the dose 1.25 mg at 24 months (RR 1.93, 95% CI 1.48 to 2.52).No significant increased risk of discontinuation due to serious adverse events was observed for fingolimod 0.5 mg compared to placebo at six and 24 months. A significant increased risk of discontinuation due to serious adverse events was found for fingolimod 5.0 mg (RR 2.77, 95% CI 1.04 to 7.38) compared to placebo at six months.Comparing fingolimod 0.5 mg to intramuscular interferon beta-1a, we found moderate quality evidence that the drug at one year slightly increased the number of participants free from relapse (RR 1.18, 95% CI 1.09 to 1.27) or from gadolinium-enhancing lesions (RR 1.12, 95% CI 1.05 to 1.19), and decreased the relapse rate (rate ratio 0.48, 95% CI 0.34 to 0.70). We did not detect any advantage for preventing disability progression (RR 1.02, 95% CI 0.99 to 1.06; low quality evidence). We did not detect any significant difference for MRI T2-weighted lesion load change.We found a greater likelihood of participants discontinuing fingolimod, as compared to other DMDs, due to adverse events in the short-term (six months) (RR 3.21, 95% CI 1.16 to 8.86), but there was no significant difference versus interferon beta-1a at 12 months (RR 1.51, 95% CI 0.81 to 2.80; moderate quality evidence). A higher incidence of adverse events was suggestive of the lower tolerability rate of fingolimod compared to interferon-beta 1a.Quality of life was improved in participants after switching from a different DMD to fingolimod at six months, but this effect was not found compared to placebo at 24 months.All studies were sponsored by Novartis Pharma.

AUTHORS' CONCLUSIONS

Treatment with fingolimod compared to placebo in RRMS patients is effective in reducing inflammatory disease activity, but it may lead to little or no difference in preventing disability worsening. The risk of withdrawals due to adverse events requires careful monitoring of patients over time. The evidence on the risk/benefit profile of fingolimod compared with intramuscular interferon beta-1a was uncertain, based on a low number of head-to-head RCTs with short follow-up duration. The ongoing trial results will possibly satisfy these issues.

Retinal nerve fiber layer sector-specific compromise in relapsing and remitting multiple sclerosis

Objective

To evaluate quadrant and sector retinal nerve fiber layer (RNFL) thickness and total macular volume (TMV) in relapsing–remitting multiple sclerosis (RR-MS) patients.

Methods

Optical coherence tomography measures of RNFL and TMV were studied in 321 eyes without prior optic neuritis (ON) (MS unaffected), 151 eyes with prior ON (MS affected), and 148 healthy control eyes.

Results

Mean RNFL thickness was significantly lower in the MS affected and MS unaffected groups relative to the control group (p < 0.0001). RNFL thicknesses in the superior, inferior, and temporal quadrants were significantly reduced in MS unaffected (113 ± 15 μm, 119 ± 17 μm, 63 ± 13 μm) (p < 0.001) and MS affected groups (99 ± 19 μm, 103 ± 21 μm, 51 ± 13 μm) (p < 0.0001) compared with that in controls (120 ± 14 μm, 128 ± 15 μm, 69 ± 8 μm, respectively). TMV was significantly reduced in both the MS affected and MS unaffected groups compared with that in the controls (p < 0.0001).

Conclusion

Quadrant, sector, and PMB RNFL thicknesses are significant individual measures in RR-MS for both affected and unaffected eyes and may prove valuable in future investigations including biomarker and outcomes research.

•

We detailed RNFL quadrant and sector segmentation analysis in multiple sclerosis.

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RNFL sector thicknesses were lower in 2 affected eyes relative to 1 affected eye.

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PMB thickness distinguishes MS affected and MS unaffected groups from controls.

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TMV thickness distinguishes MS affected and MS unaffected groups from controls.

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EDSS correlated with RNFL for unaffected group and TMV for affected group.

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.

Clinical trials to clinical use: using vision as a model for multiple sclerosis and beyond

Optical coherence tomography (OCT) has made possible the structure-function correlations that uniquely characterize the afferent visual pathway as a model for understanding multiple sclerosis (MS) and for developing new treatments. During the past decade, OCT measures of retinal nerve fiber layer (RNFL) and ganglion cell/inner plexiform layer (GCL + IPL) thickness have evolved from being a means to validate visual function tests, such as low-contrast letter acuity, to provide a window on the axonal and neuronal loss that are now widely recognized as contributors to permanent visual dysfunction in MS. Although acute optic neuritis (ON) leads to thinning of the RNFL by 20%-40% within 3 months after a single episode, thinning of the RNFL and GCL + IPL occur over time in MS eyes even in the absence of an acute ON history. As such, OCT and its functional and patient-reported correlates of low-contrast acuity and vision-specific quality of life (QOL) have now been incorporated into MS clinical trials. Results of an ongoing, phase 2 trial of a remyelinating agent that uses acute ON as a model for assessing therapeutic efficacy will define even further the important role for OCT in documenting structural changes as we move forward from clinical trials to clinical use.

Vision and vision-related outcome measures in multiple sclerosis

Visual impairment is a key manifestation of multiple sclerosis. Acute optic neuritis is a common, often presenting manifestation, but visual deficits and structural loss of retinal axonal and neuronal integrity can occur even without a history of optic neuritis. Interest in vision in multiple sclerosis is growing, partially in response to the development of sensitive visual function tests, structural markers such as optical coherence tomography and magnetic resonance imaging, and quality of life measures that give clinical meaning to the structure-function correlations that are unique to the afferent visual pathway. Abnormal eye movements also are common in multiple sclerosis, but quantitative assessment methods that can be applied in practice and clinical trials are not readily available. We summarize here a comprehensive literature search and the discussion at a recent international meeting of investigators involved in the development and study of visual outcomes in multiple sclerosis, which had, as its overriding goals, to review the state of the field and identify areas for future research. We review data and principles to help us understand the importance of vision as a model for outcomes assessment in clinical practice and therapeutic trials in multiple sclerosis.

Optical coherence tomography for retinal imaging in multiple sclerosis

Visual disturbances caused by inflammatory and demyelinating processes of the visual system, mainly in the optic nerve, are a common symptom in multiple sclerosis (MS). Optical coherence tomography (OCT) is a tool that is increasingly used for quantifying retinal damage in MS and other neurologic diseases. Based on spectral interferometry, it uses low-coherent infrared light to generate high-resolution spatial images of the retina. The retinal nerve fiber layer (RNFL) consists of unmyelinated axons that form the optic nerve, and thus represents a part of the central nervous system. OCT allows for noninvasive measurements of RNFL thickness in micrometer resolution. With the help of OCT, researchers have managed to demonstrate that eyes of MS patients show distinct RNFL thinning after an event of acute optic neuritis in MS, and even subclinical damage in eyes with no previous optic neuritis. OCT is also a useful tool in terms of providing a differential diagnosis of MS toward, for example, neuromyelitis optica, a disease that usually shows stronger retinal thinning, or Susac syndrome, which is characterized by distinct patchy thinning of the inner retinal layers. RNFL thinning is associated with magnetic resonance imaging-derived measurements of the brain, such as whole-brain atrophy, gray and white matter atrophy, and optic radiation damage. These features suggest that OCT-derived retinal measurements are a complement for measuring central nervous system neurodegeneration in the context of clinical trials – for example, with neuroprotective substances.

Comparative skull analysis suggests species-specific captivity-related malformation in lions (Panthera leo)

Lion (Panthera leo) populations have dramatically decreased worldwide with a surviving population estimated at 32,000 across the African savannah. Lions have been kept in captivity for centuries and, although they reproduce well, high rates of stillbirths as well as morbidity and mortality of neonate and young lions are reported. Many of these cases are associated with bone malformations, including foramen magnum (FM) stenosis and thickened tentorium cerebelli. The precise causes of these malformations and whether they are unique to captive lions remain unclear. To test whether captivity is associated with FM stenosis, we evaluated 575 lion skulls of wild (N = 512) and captive (N = 63) origin. Tiger skulls (N = 276; 56 captive, 220 wild) were measured for comparison. While no differences were found between males and females or between subadults and adults in FM height (FMH), FMH of captive lions (17.36±3.20 mm) was significantly smaller and with greater variability when compared to that in wild lions (19.77±2.11 mm). There was no difference between wild (18.47±1.26 mm) and captive (18.56±1.64 mm) tigers in FMH. Birth origin (wild vs. captive) as a factor for FMH remained significant in lions even after controlling for age and sex. Whereas only 20/473 wild lions (4.2%) had FMH equal to or smaller than the 5^th percentile of the wild population (16.60 mm), this was evident in 40.4% (23/57) of captive lion skulls. Similar comparison for tigers found no differences between the captive and wild populations. Lions with FMH equal to or smaller than the 5^th percentile had wider skulls with smaller cranial volume. Cranial volume remained smaller in both male and female captive lions when controlled for skull size. These findings suggest species- and captivity-related predisposition for the pathology in lions.