Abstract
Abstract: :
Purpose:The lacrimal film has a trophic, immunological, antimicrobial and anti–inflammatory role. The lipidic phase of the tear film reduces the surface stresses and limits tear evaporation. We present a reproducible and non–invasive investigation of the lacrimal film, the Video–Tearscope (Vi–Te) that allows to analyze the after–blinking tear stabilization time and the different types of blinking. Vi–Te consists of a numerical video recording of the specular reflexion produced by the Tearscope Plus adapted to a biomicroscope. Methods:Thirty normal subjects and 32 patients with a dry eye syndrome were included. We studied the blinking types and lacrimal film stabilization time (LFST) and its speed from both open and closed eyes using the Vi–Te technique. The analysis was carried out at 25 images/sec., corresponding to an in–between image interval of 40 milliseconds. Results:Four types of spontaneous blinking were observed: complete, subtotal (99 to 70% of occlusion), partial (69 to 20%) and abortive (less than 20%). We obtained a mean LFST of 1,06±0,42 sec. with an average speed of 6,8±1,4 mm/sec. for the control group versus 2,02±0,93 sec. with 5,09±1,67 mm/sec for the dry eye syndrome group. The differences were significant between the two groups for the LFST (p<0,0001) and the stabilization speeds (p=0,008) for complete blinking. There was a significant correlation between the blinking type and the LFST: the more complete the blinking was, the shorter was the stabilization time. A negative correlation was also found between the LFST and the tear break–up time. Conclusions:The Video–Tearscope is a promising technique that provides new insights on the tear film stability and physiology. The main weakness of this technique however is the time required for video analysis (20–45 min. per case). Despite this drawback, additional studies should be undertaken in order to allow us to establish standards for evaluating ocular surface disorders in a completely noninvasive way.
Keywords: cornea: tears/tear film/dry eye • imaging/image analysis: clinical • cornea: surface mucins