Abstract
Purpose :
Ocular surface inflammation, including dry eye disease (DED) has been described in keratoconus (KC) patients. Tear osmolarity (TO) has been shown to be a sensitive and specific parameter to detect dry eye and to assess the disease activity. We hypothesized that DED status in KC patients is correlated to KC severity.
Methods :
This cross sectional study enrolled 61 patients (36 male, 25 female; mean age 32,2± 13,5y SD) previously diagnosed with KC and recruited in an ophthalmologic center in Chapecó City, Southwest Brazil. All subjects underwent complete eye examination.Inclusion criteria was KC diagnosis. Exclusion criteria was contact lens wear, eye drops use, pregnancy, brestfeeding, glaucoma and previous eye surgery. Tear osmolarity measures obtained by a portable osmometer (TearLab Osmolarity System,San Diego, CA) and Scheimpflug images parameters were performed in all patients, both eyes, by the same examinator. DED was assumed by considering the highest eye TO (>= 308mOsm/l for mild cases, >=312 mOsm/l for moderate cases and >= 318 mOsm/l for severe cases). KC diagnosis and severity were confirmed by using Bellin/Ambrosio deviation display (BAD-d). All patients agreed to participate in the study and had given their informed consent.The KC subjects were divided in four groups according to DED classification (normal, mild, moderate and severe) and compared to KC severity using the highest BAD-d in each subject. For statistical analysis, Kruskall-Walis, ANOVA, t-student, likelihood ratio and Dunn tests were performed.
Results :
In this study, 83,6% KC patients (51/61) had DED (TO >=308 mOsm/l), among them 54% (33/61) with severe DED. No statistical differences in KC groups concerning age or gender were observed. KC patients with severe DED had a statistically higher BAD-d when compared to no DED KC patients (8,4±3,9; p=0,003).
Conclusions :
In this study DED was found in the majority of KC patients, especially in advanced KC, assumed by greater values of TO in the worse eye. This finding supports the hypothesis that inflammation on the ocular surface is present in KC patients and might plays a role in the progression of KC. We speculate that as the corneal curvature becomes more irregular and steeper in severe KC, it might contribute to tear film instability and consequently more chance to develop DED.. Future studies are necessary to understand these findings and the impact on KC evolution.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.