Debido a la gran importancia fisiologica y optica que representa la pelicula lagrimal para el correcto funcionamiento del ojo humano, una acertada evaluacion y diagnostico de cualquier tipo de anomalia o alteracion, ya sea en sus mecanismos de secrecion, estabilidad o calidad, de una o todas sus capas, se convierte en una imperiosa necesidad para la practica optometrica y oftalmologica. La evaluacion de la pelicula preocular lagrimal (PLPO) es de gran ayuda diagnostica en salud visual. En muchos paises se vienen empleando tecnicas no invasivas, basadas en interferometria1 ,2 ,3 ; las tecnicas invasivas (BUT) tiempo de rompimiento de la pelicula lagrimal, han demostrado no tener validez significativa por su baja reproducibilidad4 ,5 y por provocar una alteracion bioquimica de la pelicula lagrimal, inducida por la fluoresceina. Este estudio se llevo a cabo con el fin de evaluar una tecnica de rompimiento de la pelicula lagrimal no invasiva (BUTNI) con Tearscope® de Keeler U.K., basada en principios fisicos de interferometria, a traves de colores de interferencia generados por las diferentes longitudes de onda6 ,7 ,8 . Este instrumento mide el espesor de la capa lipidica y el reservorio lagrimal, e igualmente permite observar la calidad de la pelicula lagrimal. Se escogio una muestra de 60 sujetos presumiblemente sanos (n= 60), de acuerdo con los criterios de inclusion y exclusion y por medio del cuestionario validado McMonnies 9 ,10 ,11, para diagnostico de ojo seco, se evaluaron ambos ojos. Con el f*in de descartar alteraciones en la vision del color, los examinadores fueron sometidos a la prueba Farnsworth D1512 para evitar sesgos en la observacion de los patrones de colores con el Tearscope®. En una primera sesion se evaluaron el BUTNI\h 7,\h 8, BUT con fluoresceina al 2% (FulGlo) y Schirmer Test I13 ,14 ,15 y en la segunda sesion Schirmer Test II con proximetacaina al 0,5%, para evitar la interaccion farmacologica entre proximetacaina y fluoresceina. Los datos se procesaron en Excel, EPI Info 6 y Epidat 3.0.AbstractPreocular tear film (POTF) evaluation is a main diagnostic issue in primary visual care. A comprehensive evaluation of its anomalies, POTF layers’ stability, quality and secretor mechanisms should be mandatory in Optometric and Ophthalmologic practice. Most countries worldwide are using recently developed POTF non invasive techniques, interferometry based\h 1,\h 2,\h 3. Some other investigators have proven that the invasive technique breakup time (BUT) does not have a significant value because of its low reproducibility\h 4,\h 5 also, due to fluorescein induced biochemical tear film alteration. This study has been made in order to evaluate a non invasive beak-up-time technique (NIBUT), based on physical principles of interferometry through interferometric colors generated by the various wave- length, by means of Tearscope® from Keeler U.K.\h 6,\h 7,\h 8. This instrument measures tear film’s lipid layer thickness and reservoir, also, tear film’s quality can be observed. The study sample was 60 presumably healthy subjects (n=60) according to inclusion and exclusion criteria and by means of the validated McMonnies questionnaire for dry eye\h 9,\h 10,\h 11. Both eyes were evaluated. In order to rule out vision color anomalies, chosen examiners underwent Farnsworth D15 test to avoid NIBUT’s\h 7,\h 8 interferential colors patterns misjudge during observation\h 12 with Tearscope®. On a first session NIBUT, BUT with fluorescein 2% (FulGlo) and Schirmer Test I\h 13,\h 14,\h 15 were evaluated. Schirmer Test II with proximetacaine 0,5% was evaluated on the second session to avoid a pharmacologic interaction between proximetacaine and fluorescein. Analysis statistical data software used were Excel, EPI Info 6 and Epidat 3.0.According to the results, NIBUT’s sensibility and specificity were 65,9% and 62,5% respectively,versus gold test (BUT). Most frequently color pattern reported was First Order Pattern, which corresponds to a lipid layer of 90 to 140nm (26%). In 85% of the population the break-up-time for POTF was less than 23 seconds. Burning and foreign body symptoms versus NIBUT had higher sensibility and specificity: 74% and 71,4% respectively while for BUT they were 58% and 60,7%. Schirmer I test reported 42,9% sensibility for burning, 20,8% for irritation and 95,7% specificity for burning and 91,7% for irritation. Schirmer II test reported 21,1% sensibility for irritation and a high specificity for irritation and burning: 90,9% and 80%. In contrast tear reservoir presented 44,7% sensibility for irritation and 40% for burning while specificity related to irritation was 63,6%, 59,4 for dryness and 50% for burning.
