Tear film break-up time evaluated by real-time Hartmann-Shack wavefront sensing.
OBJECTIVE
To develop a novel method for measuring tear break-up time (BUT) by continuously measuring higher order wavefront aberrations using a Hartmann-Shack (H-S) aberrometer.


METHODS
Wavefront aberrations up to the sixth order for a 4-mm pupil were measured in six eyes of six normal subjects using an H-S aberrometer. The aberrometry was performed once every second for up to 50 s under topical anesthesia. The sequence of the points was divided into two stages, and the BUT was defined as the wavefront border of the stages (WFBUT). The WFBUT was compared with the BUT by the conventional fluorescein method (FLBUT) or by the disruption of placid-ring images (PLBUT).


RESULTS
In three eyes, the WFBUT (average, 10.9 +/- 1.1 s) was shorter than the PLBUT (average, 17.5 +/- 2.5 s), while in the other three eyes the WFBUT (average, 21.5 +/- 2.2 s) was longer than PLBUT (average, 8.1 +/- 2.2 s). The FLBUT was shorter than WFBUT or PLBUT in most cases.


CONCLUSIONS
The tear break-up time measured by H-S aberrometer may be used as a practical measure of tear break-up.
Mihashi
Toshifumi
T
Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan.
Hirohara
Yoko
Y
Koh
Shizuka
S
Ninomiya
Sayuri
S
Maeda
Naoyuki
N
Fujikado
Takashi
T
D000328:Adult; D001251:Astigmatism / Q000175:diagnosis*; D003287:Contrast Media / Q000008:administration & dosage; D003941:Diagnostic Techniques, Ophthalmological; D019793:Fluorescein / Q000008:administration & dosage; D006801:Humans; D009883:Ophthalmic Solutions; D012016:Reference Values; D015203:Reproducibility of Results; D013666:Tears / Q000502:physiology*
D003287:Contrast Media; D009883:Ophthalmic Solutions; D019793:Fluorescein