An analytical longitudinal observational study on the association of Vitamin D insufficiency in subjects with primary (idiopathic) demyelinating optic neuritis using visual evoked potential and optical coherence tomography

Background: Optic neuritis (ON) is an acute and often immune-mediated inflammatory condition of the optic nerve. Vitamin D acts as an anti-inflammatory agent and may confer neuroprotection. Visual evoked potential (VEP) and optical coherence tomography (OCT) are emerging tools for demyelinating diseases. Aims and Objectives: We tried to correlate between Vitamin D insufficiency and acute demyelinating ON using different parameters such as VEP, ganglion cell layer (GCL) thickness, and retinal nerve fiber layer (RNFL) thickness. Materials and Methods: This observational longitudinal analytical study included thirty non-consecutive patients with primary ON and 30 healthy controls. All patients with ON underwent detailed clinical and ophthalmological examination, and detailed blood workup, including serum 25 (OH) Vitamin D. VEP P100 latency, amplitude, OCT, RNFL thickness, and GCL thickness at presentation and after 3 months from May 2019 to November 2020. Results: Vitamin D insufficiency (below 30 ng/mL) was present in 60% of cases of ON. The baseline VEP showed significantly prolonged P100 latency in affected eyes in the Vitamin D insufficient group (mean 129.78±7.97 ms vs. 121.0±4.99 ms) whereas the P100 amplitude was not significantly altered between the two groups (5.5±3.13 μV vs. 7.08±3.01 μV). The baseline RNFL thickness (132.21±10.69 μm vs. 118.01±10.4 μm) and GCL thickness (76.82±2.04 μm vs. 73.06±3.2 μm) were greater in affected eyes of vitamin D insufficiency ON. There was greater RNFL thinning (79.93±3.42 μm vs. 74.80±3.5 μm) and GCL thinning (64.78±1.9μm vs. 69.02±2.22 μm) in affected eyes of ON with Vitamin D insufficiency at 3 months. Conclusion: Vitamin D insufficiency was found in most cases of ON. Insufficient Vitamin D positively correlated with optic nerve affection severity as evidenced by significantly increased baseline thickness of RNFL and GCL and more thinning of RNFL and GCL at the end of 3 months of follow-up

Retinal nerve fiber layer thinning found in amyotrophic lateral sclerosis – Correlation with disease duration and severity

Purpose: The retinal involvement of amyotrophic lateral sclerosis (ALS) is a novel idea about a possible correlation between retinal nerve fiber layer (RNFL) thickness in different spectra of ALS patients. Finding the association of RNFL with disease duration and severity will help identify a novel noninvasive biomarker. Methods: The study was designed as a cross-sectional study and was conducted with a suitable proforma. We included the ALS cases based on the revised El Escorial criteria. Healthy controls were age and gender matched. We used the revised ALS functional rating scale (ALSFRS-R) to assess the operational status of the patients. We measured RNFL thickness in the four quadrants with spectral-domain optical coherence tomography (OCT) and analyzed it. Results: We included 30 cases (60 eyes) and 10 healthy controls (20 eyes) having a mean (standard deviation [SD]) age of 49.5 (11.1) years with a median of 50 years, and a majority of them (65%) were middle aged (between 41 and 60 years). We found statistically significant differences in RNFL thicknesses between ALS patients and healthy controls. On segmental analysis, the right eye superior and nasal quadrants and the left eye superior, inferior, and nasal quadrants were significantly affected, along with a gross asymmetry found between the left and right eyes among ALS patients. There was a significant decrease in average RNFL thickness in definite ALS patients than probable ALS patients, with significantly reduced average RNFL thickness in moderate to severe ALS patients. On correlation analysis, disease duration showed a good negative correlation with bilateral average RNFL thickness, and the ALSFRS-R score demonstrated a good positive correlation with bilateral average RNFL thickness, which was statistically significant. Thus, a reduced bilateral RNFL thickness is associated with a decreased ALSFRS-R score. Conclusion: The retinal changes can serve as a marker for diagnosing and monitoring patients with ALS