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Nisha Mukherjee, Anthony N Kuo, Richard Bedlack, Henry Tseng; Imaging amyotrophic lateral sclerosis (ALS) neurodegeneration through the eye. Invest. Ophthalmol. Vis. Sci. 2014;55(13):3364.
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© ARVO (1962-2015); The Authors (2016-present)
Recent studies on optineurin suggest similarities in pathophysiology between glaucoma and neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), but it is currently unclear whether neurodegeneration occurs in neurons beyond the brain and spinal cord in ALS. We hypothesized that ALS patients may exhibit retinal neurodegeneration, and tested this hypothesis by using spectral domain optical coherence tomography (SD-OCT) imaging.
ALS patients were recruited from the Duke University Medical Center under an IRB approved protocol. We performed visual acuity (VA) testing, intraocular pressure (IOP) measurement, and an anterior and undilated posterior segment evaluation when possible. Retinal neurodegeneration was assessed by measuring retinal nerve fiber layer (RNFL) thickness using SD-OCT (Spectralis; Heidelberg Engineering). Mean RNFL thickness and 6-sector RNFL thickness were compared to the normative database. ALS disease severity was determined through the ALS Functional Rating Scale (ALSFRS-R) scale and analyzed for statistical correlation with RNFL thickness.
16 patients with ALS were enrolled with a mean ALSFS-R score of 31.8 (±9.9). The male: female ratio was 10:6. The average age was 61.1 years. Mean VA was 20/40 in each eye. IOP in 15 patients were within normal limits and slit lamp examination in all patients were normal. No significant optic nerve cupping was observed. SD-OCT imaging was successfully performed in all ALS patients despite positional challenges resulting from motor deficits. Mean RNFL thickness for this group was 90.06 µm in the right eye (±10.97 µm) and 87.31 µm in the left eye (±13.20 µm). Preliminary assessment did not reveal a correlation between total RNFL thickness and ALS severity.
Our study shows that OCT imaging can be performed rapidly and effectively in ALS patients despite positional challenges. While we did not detect significant retinal thinning in ALS patients, future work on sublayer segmentation and analysis are needed. OCT imaging provides a valuable non-invasive technique for evaluating retinal anatomy and neurodegenerative changes. Use of this technology in ALS patients may reveal the utility of using the retina as a biomarker to diagnose and detect progression in ALS.
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