No abstract

Objective-Cross-sectional studies of optical coherence tomography (OCT) show that retinal nerve fiber layer (RNFL) thickness is reduced in multiple sclerosis (MS) and correlates with visual function. We determined how longitudinal changes in RNFL thickness relate to visual loss. We also examined patterns of RNFL thinning over time in MS eyes with and without a prior history of acute optic neuritis (ON).Methods-Patients underwent OCT measurement of RNFL thickness at baseline and at 6-month intervals during a mean follow-up of 18 months at three centers. Low-contrast letter acuity (2.5%, 1.25% contrast) and visual acuity (VA) were assessed.Results-Among 299 patients (593 eyes) with ≥6 months follow-up, eyes with visual loss showed greater RNFL thinning compared to eyes with stable vision (low-contrast acuity, 2.5%: p<0.001; VA: p=0.005). RNFL thinning increased over time, with average losses of 2.9 μm at 2-3 years and 6.1 μm at 3-4.5 years (p<0.001 vs. 0.5-1-year follow-up interval). These patterns were observed for eyes with or without prior history of ON. Proportions of eyes with RNFL loss greater than test-retest variability (≥6.6 μm) increased from 11% at 0-1 year to 44% at 3-4.5 years (p<0.001).Interpretation-Progressive RNFL thinning occurs as a function of time in some patients with MS, even in the absence of ON, and is associated with clinically significant visual loss. These findings are consistent with sub-clinical axonal loss in the anterior visual pathway in MS and support the use of OCT and low-contrast acuity as methods to evaluate the effectiveness of putative neuroprotection protocols.Address all correspondence to: Dr. Laura J. Balcer, Department of Neurology, 3 E. Gates, 3400 Spruce Street, Philadelphia, PA 19104, 215-349-8072, Fax 215-349-5579, lbalcer@mail.med.upenn.edu. NIH Public Access Author ManuscriptAnn Neurol. Author manuscript; available in PMC 2011 June 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptVisual dysfunction is a common cause of disability and reduced quality of life in multiple sclerosis (MS). 1 The anterior visual pathway is a frequent site for inflammation and demyelination, and axonal degeneration is likely to be a final common pathway to permanent visual loss. [2][3][4][5] Recognized by MS experts as a critical dimension for outcomes assessment, 6 vision has been an important area of investigation. The findings of many studies have supported low-contrast letter acuity as a candidate clinical trial outcome measure. It can capture subtle visual impairment, treatment effects, MRI lesion burden, prolonged visual evoked potential latencies, and quality of life. 1,[7][8][9][10][11][12][13] Many ongoing MS trials have incorporated low-contrast acuity as a tertiary outcome.The emergence of optical coherence tomography (OCT) in MS has brought the anterior visual pathway to the forefront as a model for measuring therapeutic efficacy, particularly for trials involving neuroprotection. 14-32 A reliable marker for axonal loss in MS, 24 retina...

Objective: To evaluate the retinal nerve fiber layer (RNFL) thickness and macular volume in neuromyelitis optica (NMO) spectrum patients using optical coherence tomography (OCT).Background: OCT can quantify damage to retinal ganglion cell axons and can identify abnormali-

Background: Most of Multiple Sclerosis (MS) patients without previous optic neuritis (ON) show

SummaryThe pathophysiology of multiple sclerosis (MS) is characterized by demyelination, which culminates in a reduction in axonal transmission. Axonal and neuronal degeneration seem to be concomitant features of MS and are probably the pathological processes responsible for permanent disability in this disease. The retina is unique within the CNS in that it contains axons and glia but no myelin, and it is, therefore, an ideal structure within which to visualize the processes of neurodegeneration, neuroprotection, and potentially even neurorestoration. In particular, the retina enables us to investigate a specific compartment of the CNS that is targeted by the disease process. Optical coherence tomography (OCT) can provide high-resolution reconstructions of retinal anatomy in a rapid and reproducible fashion and, we believe, is ideal for precisely modeling the disease process in MS. In this Review, we provide a broad overview of the physics of OCT, the unique properties of this method with respect to imaging retinal architecture, and the applications that are being developed for OCT to understand mechanisms of tissue injury within the brain.