PURPOSE: To evaluate and compare the tear-film dynamics in normal eyes and in eyes with milddry-eye symptoms using a new noninvasive optical method based on a double-pass instrument.
SETTING: Hospital Universitario Virgen de la Arrixaca, Murcia, Spain.
DESIGN: Evaluation of diagnostic test or technology.
METHODS: Dynamic recording of double-pass retinal images during unforced tear-film breakupwas performed in eyes with mild dry-eye symptoms (study group) and in an asymptomatic controlgroup. Series of consecutive retinal images were recorded every 0.5 seconds while the patientavoided blinking. Measurements were performed under low-light conditions to naturally increasepupil diameter and maximize the method’s sensitivity. Additional clinical tests were performedfor comparison and included tear breakup time (TBUT), Schirmer I tests, and a normalized questionnaire(McMonnies). From the retinal images, a quality metric, the intensity distribution index,was calculated. An objective TBUT value was estimated in each eye when the intensity distributionindex surpassed a defined threshold value compared with the initial baseline.
RESULTS: The study group comprised 20 eyes and the control group, 18 eyes. Symptomatic dryeyes had a typical exponential increase in the intensity distribution index with time. The objectiveTBUT values in the study group were comparable to the clinical TBUT estimates.
CONCLUSIONS: The new objective optical method to evaluate the quality and stability of the tear filmwas sensitive in detecting mild symptoms of dry eye and differentiating from normal cases. The proceduremay allow early detection and follow-up of patients’ tear film–related complaints.
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