Abstract
Purpose: :
To investigate characteristics of dry eyes with short tear film break-up time (BUT) without aqueous deficiency by comparison with dry eyes with aqueous deficiency
Methods: :
Forty three eyes of 43 patients (3 males, 40 females; mean age: 57.0±13.0 years; range: 26 to 78 years) with dry eye symptoms were divided into two groups, short BUT without aqueous deficiency (SB) (Schirmer value > 5mm and BUT < 5s) and aqueous deficiency (AD) (Schirmer value ≤ 5mm and BUT < 5s) groups. Questionnaire of subjective symptoms, vital staining of epithelia of ocular surface, tear lipid layer interferometry, and visual function tests using functional visual acuity (FVA) measurement and tear stability analysis system (TSAS) were performed. Goblet cell density and keratinization in bulbar conjunctival epithelia obtained by nitrocellulose filter-paper stripping (impression cytology) were studied using PAS staining. Quantitative real-time PCR was used to determine the mRNA expression of MUC5AC and MUC16 in the bulbar conjunctival epithelia obtained by brush cytology.
Results: :
SB and AD group was consisted with 15 eyes (1 male, mean age: 50.5±15.2 years) and 28 eyes (2 males, 60.4±10.6 years), respectively. Mean age of the SB group was significantly younger than that in the AD group (P=0.038). Symptom scores were comparable between the two groups. Eyes with epithelial damages (vital staining scores > 3/9 points) were significantly less common in the SB group than the AD group (P=0.0032). Visual maintenance ratio (VMR) calculated by FVA tests were comparably decreased in the SB and AD groups. Grading of tear lipid layer interference patterns showed that mean score in the AD group was significantly higher than in SB (P= <.001). Indices of irregular astigmatism measured by TSAS were comparably high in the SB and AD groups. Decreased goblet cell density and keratinized conjunctival epithelia were observed in both groups. There was no difference in the mRNA expressions of MUC5AC and MUC16 between the two groups.
Conclusions: :
Eyes with short BUT without decreased tear secretion had strong irritating symptoms. Although they showed less epithelial damages, visual functions were deteriorated as in aqueous deficiency eyes. The results suggested that tear film instability may be an independent category of dry eyes other than aqueous deficiency.
Clinical Trial: :
Institutional Review Board
Keywords: cornea: tears/tear film/dry eye • cornea: surface mucins • cornea: clinical science