Abstract
Purpose: :
Short breakup time dry eye (SBUTDE) is a disorder which is characterized by a short fluorescein breakup time (FBUT) and severe ocular symptoms. SBUTDE does not generally accompany tear deficiency and produces minimal ocular surface damage. In this study, various ocular-surface examinations were performed on SBUTDE and eyes with a reduced FBUT (≤5 sec.) due to other causes (abnormal BUT - ABUT).
Methods: :
Thirteen eyes from 13 SBUTDE subjects [age: 51.3±12.8 (mean±SD) yrs.] and 33 eyes from 33 ABUT subjects (age: 52.9±13.8 yrs.) were compared. All enrolled subjects had no meibomian gland dysfunction. Examinations were performed on study eyes in the order of least to most invasive as follows: 1) measurement of the radius (R) of the lower, central tear meniscus by meniscometry, 2) measurement of the initial velocity of the tear film lipid layer (TFLL) spread [H’(0), mm/sec.] using a cross-correlation method and the rheological Voigt model, 3) measurement of the non-invasive BUT (NIBUT), in seconds with a video-interferometer (DR-1TM; Kowa Co. Ltd., Japan), 4) measurement of the FBUT, 5) evaluation of epithelial damage by summing the scores for punctate fluorescein staining on the cornea and conjunctiva [OSED score; scores: from 0 (none) to 9 (most severe)], and 6) the Schirmer 1 test (ST1). The results from both groups were then compared and discriminant analysis was performed using logistic regression.
Results: :
Examined values (SBUTDE; ABUT) were R (0.23±0.08; 0.21±0.09), H’(0) (6.5±2.8; 3.3±3.1), NIBUT (4.4±2.0; 4.7±3.7), FBUT(1.5±1.2; 2.1±1.5), OSED score (0.92±1.2; 3.8±3.3), and ST1 (19.5±13.3; 7.9±8.7). Significant differences were found between the two groups in H’(0), OSED score, and ST1 (p<.005). Discriminant analysis showed that error rate for discrimination was 4.3% (proportion of right answers: 95.7%) [Linear discriminant function: 1.3x(NIBUT)-0.86xH’(0)+0.98xOSED score-3.2].
Conclusions: :
SBUTDE may be differentially diagnosed from ABUT based on examinations including H’(0), NIBUT, and OSED score. In SBUTDE, H’(0) is greater and OSED score is lesser than those in ABUT
Keywords: cornea: tears/tear film/dry eye