Abstract
Purpose :
Inflammation and neurosensory abnormalities are considered among etiological factors of dry eye disease (DED). The purpose of the current study was to compare clinical features among subtypes of DED classified based on corneal nerve and dendritiform cell (DC) densities by in vivo confocal microscopy (IVCM).
Methods :
In this retrospective cohort study, IVCM images of subbasal layer of the central cornea of 294 eyes of 294 patients with DED were analyzed for corneal nerve and DC densities. Cut-offs were determined as 84.6±8.8 cells/mm2 for DCs and as 15.942.2±1,135.7 μm/mm2 for corneal nerves based on mean±2SD of normal controls. Patients with DED were classified in 4 groups based on IVCM findings:1) normal nerve and DC density; 2) normal nerve and high DC density; 3) low nerve and normal DC density;4) low nerve and high DC density, and clinical sign and symptoms compared.
Results :
The intensity of pain within the last 24 h on OPAS showed significantly (p=0.047) higher scores in groups 3 (1.72±0.35) and 4 (0.81±0.33) compared to 1(0.56±0.23) and 2 (0.33±0.19). The global impact of pain on QoL was higher in groups 1 (2.50±0.51), 3 (2.35±0.34) and 4 (1.96±0.61) compared to 2 (0.52±0.52), with near significance among groups (p=0.051). Notably, there was a significant change in the percentage of time spent thinking about eye pain among QoL subscores across the groups (p=0.028). On OSDI, reading (p=0.003), computer (p=0.008), and TV(p=0.005) tasks were significantly higher in group 4 (2.28±0.32;2.05±0.36;1.88±0.27, respectively) compared to groups 1 (1.00±0.19; 1.27±0.21; 1.28±0.22, respectively), 2 (0.38±0.18;0.29±0.18;0.50±0.27, respectively) and 3 (1.07±0.16;1.00±0.15; 0.92±0.14, respectively). Significant changes were observed in corneal staining among groups (p=0.028), with higher values in groups 3(4.00±1.40),4 (3.34±0.97) and 1 (4.03±0.89) compared to 2 (0.80±0.21), while no statistically significant differences were reported in disease severity (p=0.217), distribution of central pain (p=0.480), TBUT (p=0.060), Schirmer's I (p=0.275), and conjunctival staining (p=0.421).
Conclusions :
Subtypes of DED with low corneal nerve density and normal/high DC densities exhibited impaired clinical features including pain levels and QoL. This suggests a primary involvement of neurosensory abnormalities, immune activation, and inflammation in the pathogenesis of DED.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.