Background: Patterns of ganglion cell complex (GCC) loss detected by optical coherence tomography provide an objective measure of optic nerve injury. These patterns aid in early diagnosis and localization of chiasmal lesions. Methods: Twenty-three patients with chiasmal compression seen between 2010 and 2015 were imaged with the Cirrus high-definition optical coherence tomography macular cube 512 × 128, retinal nerve fiber layer (RNFL) scan protocols and automated (30-2 Humphrey) visual fields (VFs). Age-matched controls were included for comparison. Generalized estimating equations were performed comparing RNFL and GCC thicknesses between patients and their controls. Effect size (d) was calculated to assess the magnitude of difference between patients and controls. The average GCC and RNFL thicknesses also were correlated with VF mean deviation (MD). Pre operative average GCC thickness was correlated to post operative VF MD. Results: Patterns of GCC thinning corresponded to VF defects. The average GCC thickness was 67 ± 9 μm in patients and 86 ± 5 μm in controls (P < 0.001). The effect size was the greatest for GCC thickness (d = 2.72). The mean deviation was better correlated with GCC thickness (r² =0.25) than RNFL thicknesses (r² =0.15). Postoperatively, VF MD improved in 7 of 8 patients with persistent nasal GCC thinning. Six patients had no VF defect and showed statistically significant loss of GCC compared with controls (P = 0.001). Conclusions: Distinct patterns of GCC loss were identified in patients with chiasmal compression. Binasal GCC loss was typical and could be seen with minimal or no detectable VF loss. Thinning of the GCC may be detected before loss of the RNFL in some patients. After decompression, the majority of patients showed improvement in VF despite persistent GCC loss. Patients with less GCC loss before decompression had better postoperative VFs. Therefore, GCC analysis may be an objective method to diagnose and follow patients with chiasmal lesions.

This review summarizes the mechanisms and recent developments of optical coherence tomography and its practical uses in neurology. The application of optical coherence tomography imaging of the retina in multiple sclerosis, neuromyelitis optica, Alzheimer disease, and Parkinson disease are reviewed. Thinning of the peripapillary retinal nerve fibre layer has been detected in patients with optic neuritis, multiple sclerosis, neuromyelitis optica, Alzheimer disease, and Parkinson disease. However, the patterns of change differ in some aspects. The findings indicate loss of retinal ganglion cells and may reflect degenerative change in the brain in these conditions. The retinal nerve fibre layer thickness may be used as a biological marker and may help to distinguish between optic neuritis associated with multiple sclerosis and optic neuritis in neuromyelitis optica.

Research from JAMA Ophthalmology — Subretinal Fluid From Anterior Ischemic Optic Neuropathy Demonstrated by Optical Coherence Tomography

Introduction: Familial dysautonomia (FD) is a rare hereditary sensory and autonomic neuropathy (type III). The disease is caused by a point mutation in the IKBKAP gene that affects the splicing of ...

Background To define the clinical neuro-ophthalmic abnormalities of patients with familial dysautonomia (FD). Methods Sixteen patients (32 eyes) with the clinical and molecular diagnoses of FD underwent thorough neuro-ophthalmic clinical evaluation. Results Visual acuity ranged from 0.05 to 1.0 decimal units and was reduced in 15 of 16 patients. Mild to moderate corneal opacities were found in most patients but were visually significant in only 2 eyes. Red-green color vision was impaired in almost all cases. Depression of the central visual fields was present on automated visual fields in all patients, even in those with normal visual acuity. Temporal optic nerve pallor was present in all cases and was associated with retinal nerve fiber layer loss in the papillomacular region. Various ocular motility abnormalities also were observed. Conclusion Patients with FD have a specific type of optic neuropathy with predominant loss of papillomacular nerve fibers, a pattern similar to other hereditary optic neuropathies caused by mutations either in nuclear or in mitochondrial DNA, affecting mitochondrial protein function. Defects of eye movements, particularly saccades, also appear to be a feature of patients with FD.

Background: Multiple system atrophy (MSA) is a rare, adult-onset, rapidly progressive fatal synucleinopathy that primarily affects oligodendroglial cells in the brain. Patients with MSA only rarely have visual complaints but recent studies of the retina using optical coherence tomography (OCT) showed atrophy of the peripapillary retinal nerve fiber layer (RNFL) and to a lesser extent the macular ganglion cell layer complex. Methods: We performed a literature review and meta-analysis according to PRISMA guidelines for studies published before January 2017, identified through PubMed and Google Scholar databases, which reported OCT-related outcomes in patients with MSA and controls. A random-effects model was constructed. Results: The meta-analysis search strategy yielded 15 articles of which 7 met the inclusion criteria. The pooled difference in the average thickness of the RNFL was -5.48 μm (95% CI, -6.23 to -4.73; p < 0.0001), indicating significant thinning in patients with MSA. The pooled results showed significant thinning in all the specific RNFL quadrants, except in the temporal RNFL quadrant, where the thickness in MSA and controls was similar [pooled difference of 1.11 μm (95% CI, -4.03 to 6.26; p=0.67)]. This pattern of retinal damage suggests that MSA patients have preferential loss of retinal ganglion cells projecting to the magnocellular pathway (M-cells), which are mainly located in the peripheral retina and are not essential for visual acuity. Visual acuity, on the other hand, relies mostly on macular ganglion cells projecting to the parvocellular pathway (P-cells) through the temporal portion of the RNFL, which are relatively spared in MSA patients. Conclusions: The retinal damage in patients with MSA differs from that observed in patients with Parkinson disease (PD). Patients with MSA have more relative preservation of temporal sector of the RNFL and less severe atrophy of the macular ganglion cell layer complex. We hypothesize that in patients with MSA there is predominant damage of large myelinated optic nerve axons like those originating from the M-cells. These large axons may require higher support from oligodendrocytes. Conversely, in patients with PD, P-cells might be more affected.