The Differences in Tear Functions and Ocular Surface Findings Between Atopic and Vernal Keratoconjunctivitis

Abstract

Purpose: : To investigate the differences in tear functions and ocular surface health in patients with atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC)

Methods: : Twenty–four eyes of 12 patients (11 males, 1 female; age:6∼34 years) with AKC as well as 12 eyes of 6 patients with VKC( 3 males, 3 females; age:6–12 years) were studied. 20 eyes of 10 healthy control subjects (8 males, 2 females; age: 9–33 years) with no history of contact lens wear and ocular disease were also investigated. All subjects underwent measurements of tear film break up, Cochet–Bonnet corneal sensitivity, fluorescein and Rose Bengal vital stainings, conjunctival impression cytology for PAS staining and MUC 1,2,4,5AC immunohistochemistry stainings. Conjunctival brush cytology was also performed to assess the percentages of inflammatory cells and MUC1,2,4,5AC mRNA expressions in Real Time RT–PCR. Informed consents were obtained from all participants and the study followed the Guidelines of the Tenets and Declaration of Helsinki.

Results: : The mean corneal sensitivity and BUT values were significantly lower in AKC compared to patients with VKC and controls Vital staining scores were significantly higher in AKC compared to VKC and control subjects(p<0.01) . Brush cytology specimens revealed significantly higher lymphocytic infiltration in AKC and a higher eosinophilic infiltration in VKC. Impression cytology showed higher grade of squamous metaplasia and a significant decrease of goblet cell density in AKC compared to VKC and controls(p<0.01) . MUC 1, 2 and 4mRNA expressions were significantly higher AKC compared to eyes with VKC and eyes of control subjects whereas MUC5ACmRNA expression was significantly decreased in AKC relative to VKC and controls.

Conclusions: : The ocular surface disease in AKC was characterized with a higher degree of tear instability and ocular surface epithelial damage in AKC. MUC 1,2 and 4mRNA s were thought to be upregulated in response to the downregulation goblet cell MUC5ACmRNA.The differences of mucin expressions between AKC and VKC were thought to result from the differences of the inflammatory process in the two disease entities.

Keywords: conjunctiva • cornea: clinical science • cornea: tears/tear film/dry eye