Abstract
Purpose :
Hyalocytes or Macrophage-like cells (MLCs) are immune cells that respond to injury and inflammation and have an irregular, ramified, star-shape morphology.These can be seen at the vitreoretinal interface using averaged Optical Coherence Tomography (OCT) scans. Müller glial cells can appear after Internal Limiting Membrane (ILM) injury and thinning and have been described as white or hyperreflective dots in the fovea. Multiple Sclerosis (MS) is a chronic inflammatory immune disease and has multiple ocular manifestations including retinal ganglion cell atrophy and uveitis. The purpose of this study is to compare MLC and Müller cell density in the maculas of people with and without MS.
Methods :
3 people with MS (age 49±19.6 years) and 3 healthy controls (age 36.6±9.6) were included in this prospective, cross-sectional study. Multiple (ave 16, range: 8-20) 3x3mm scans centered at the macula were obtained using the OCTA protocol of a commercial device (Optovue, Inc., Fremont, CA, USA). Structural OCT volume scans were registered and averaged. Flattened slabs segmented from 0 to 5 μm above the internal limiting membrane (ILM) were used to identify cellular structures in the surface of the retina as follows using ImageJ software. Background was subtracted with a rolling ball radius of 5.0 pixels. Vessel artifacts were removed. A MaxEntropy thresholding of 33 was applied. MLCs and Müller cells were identified according to the morphology and location described in the literature and counted manually over the entire image with the Multi Point function. The slab was merged with the angiogram for display purposes.
Results :
The MLC density was higher in MS subjects (0, 2.1, 2.4 (ave 1.5±1.3)/mm2) vs (0, 0, 2.4 (ave 0.9±1.4)/mm2) for controls. Müller cell density was also higher for subjects (0.1, 0.4, 0.7 (ave 0.4±1.4)/mm2) when compared to controls (0, 0, 0.6 (0.2±0.4)/mm2).
Conclusions :
MLCs and Müller cell densities were higher on average in the maculas of people with than those without MS and may result from ocular inflammation. Further studies are needed to assess the morphology and function of these cells in MS and their role as potential biomarkers of disease.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.