Ocular Surface Disease Patients with Microneuromas also have Reduced Nerves

Abstract

Purpose : The presence of microneuromas within the subbasal nerve plexus as identified via corneal in vivo confocal microscopy (IVCM) has been associated with corneal neuropathy, including with neuropathic corneal pain. However, the association of microneuromas with other nerve and immune cell parameters has not been established.

Methods : This is a secondary analysis of a retrospective study that involved the collection of IVCM images from ocular surface disease patients. All IVCM images were viewed by the grader, and presence or absence of microneuromas was determined for each patient based on all images. In addition, three representative images from the subbasal nerve plexus were selected for each patient. ImageJ with NeuronJ plug in was used to quantify each selected image for the total, main, and branch nerve densities and count. The results from these three images were averaged. In addition the number of immune cells were counted for each image and averaged. Patients with microneuromas were compared to those without using t-test or Mann-Whitney U test as appropriate.

Results : The patients showed an average of age of 58.3 ± 1.6 years and 76.2% were female. Compared to the non-microneuroma group (NMG), the microneuroma group (MG) had a lower average total density [11,995.28 µm/mm² (range: 3,580.00-14,173.55) vs 13,806.47 (range: 0.00-26,158.00); p=0.012], average total nerve number [6.7/frame (range: 1.7-10.3) vs 8.7 (range: 0.0-23.3); p=0.014], average branch nerve density [3,082.49 µm/mm² (range: 0.00-7,205.11) vs 4,553.88 (range: 0.00-14,601.73), p = 0.044] and average branch number [3.3/frame (range: 0.0-8.0) vs 5.0 (range: 0.0-19.3), p=0.024]. There was no significant difference in main nerve density (7,054.33 ± 541.44 µm/mm² for MG; 8,373.31 ± 271.68 for NG; p=0.070), main nerve number (2.9 ± 0.3/frame for MG; 3.5 ± 0.1 for NG; p=0.094), or immune cell density [14.6/mm² (range:0.0-175.0) for MG; 35.4 (range: 0.0-285.4) for NG; p=0.144].

Conclusions : Patients with microneuromas likely also have reduced nerve density, which is more apparent in branch nerves compared to main nerves, suggesting that patients with increased nerve loss have a higher likelihood of presenting with microneuromas.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.