Corneal Confocal Microscopy In Active And Non-active Vernal Keratoconjunctivitis

Abstract

Purpose: : To study the morphologic aspects of the cornea in non-active and active vernal keratoconjunctivitis (VKC) using corneal confocal microscopy (CCM).

Methods: : Twenty three VKC patients (7 females, 16 males; age: 21 + 10 ys) were evaluated and compared to 40 eyes of 40 age-matched normal subjects (Ct). Symptoms’ score evaluations (modified QUICK questionnaire), full ophthalmological examination and CCM were performed in the non-active phase of the disease and in the active phase before treatments. ConfoScan CS4 (Nidek, Gamagori, Japan) images of the central cornea were obtained with a 40x non-contact lens and Z-ring device. The epithelial cell, endothelial cell and keratocyte densities of the central cornea, the characteristics of the stromal long nerve fibers and of the sub-basal nerve plexus (SNP) were studied.

Results: : In non-active phase all patients showed higher reflectivity and nuclear activation of the superficial epithelial cells, lower density of the basal epithelium, higher tortuosity and lower number of beadings of the SNP, lower density of keratocytes in the anterior stroma (p=0.002) compared to Ct (all p<0.001). Alterations of stromal nerve fibers were observed. In the active phase all the patients showed an objective worsening of ocular surface and reported a considerable subjective aggravation of symptoms (modified QUICK) compared to non-active phase (p=0.0001). Diameter of the superficial epithelial cells, number of activate keratocytes and anterior stroma reflectivity were significantly higher compared to both non-active phase and Ct (p=0.01); a significant worsening was observed in reflectivity of the superficial epithelium and in the basal epithelium density compared to the non-active (p=0.003). Furthermore, the number of inflammatory cells in close proximity to the sub-basal and stromal nerve fibers was more frequently detected in active VKC (78% vs 14%).

Conclusions: : The corneal involvement in VKC, even if subclinical, is associated with significant alterations of the epithelium, as well as the sub-basal and stromal corneal nerves and stroma. CCM showed morphological worsening in the corneal structures in the active phase. CCM is useful in the study of pathological in vivo corneal changes in VKC and in the monitoring of topical treatments for ocular allergic diseases.

Keywords: cornea: stroma and keratocytes • conjunctivitis • inflammation