Epithelial Immune Cell Alterations and the Effect of Anti-Inflammatory Treatment in Patients with Dry Eye Syndrome: An In Vivo Confocal Microscopy Study

Abstract

Purpose: : Dry eye is the most frequent cause for corneal consultation. IVCM allows detection of corneal immune cell alterations, implicated in the pathophysiology of dry eyes. The purpose of this study was to investigate the alterations in corneal immune cells in subtypes of dry eye syndrome (DES).

Methods: : A retrospective case control study was performed in 66 eyes with DES and compared to 28 normal eyes. Patients were divided into aqueous-deficient, evaporative, and mixed mechanism dry eye eyes based on clinical parameters. Laser IVCM, with HRT 3/Rostock Cornea Module was performed on the central cornea of patients with dry eyes and controls between 2008 and 2011. Representative images (n=3) were analyzed by two masked observers for dendritic cell (DC) density, cell body size, number of dendritic processes and area covered by each DC.

Results: : Patients with aqueous-deficient (density: p=0.001; cell area: p=0.0007; covered area: p=0.009; number of dendrites: p=0.0001) and mixed (density: p=0.03; cell area: p=0.01; covered area: p= 0.04, number of dendrites: p=0.0003), but not evaporative (density: p=0.48; cell area: 0.31; area covered: p= 0.45, number of dendrites: p=0.50), DES had significant increases for all 4 parameters as compared to controls. Patients on anti-inflammatory therapy (AIT) had 20% lower DC density and 15% decrease in size compared to patients on no AIT.

Conclusions: : IVCM enables dynamic assessment of significant DES-induced changes in immune cells, beyond slit-lamp examination. IVCM revealed increased density, size and dendrite numbers of DC, which was more pronounced in aqueous-deficient and mixed dry eyes. DC density and morphology may serve as parameters to assess severity and therapeutic efficacy and may lead to new objective measures to monitor treatment success.

Keywords: cornea: tears/tear film/dry eye • inflammation • imaging/image analysis: clinical