For the last 20 years, a great amount of evidence has accumulated through epidemiological studies that most of the dry eye disease encountered in daily life, especially in video display terminal (VDT) workers, involves short tear film breakup time (TFBUT) type dry eye, a category characterized by severe symptoms but minimal clinical signs other than short TFBUT. An unstable tear film also affects the visual function, possibly due to the increase of higher order aberrations. Based on the change in the understanding of the types, symptoms, and signs of dry eye disease, the Asia Dry Eye Society agreed to the following definition of dry eye: "Dry eye is a multifactorial disease characterized by unstable tear film causing a variety of symptoms and/or visual impairment, potentially accompanied by ocular surface damage." The definition stresses instability of the tear film as well as the importance of visual impairment, highlighting an essential role for TFBUT assessment. This paper discusses the concept of Tear Film Oriented Therapy (TFOT), which evolved from the definition of dry eye, emphasizing the importance of a stable tear film.

Increments of LV, IC, IT, and IA with age led to a reduction in the dimensions of the AC and to narrowing of the ACA. This may explain why aging is a significant risk factor for primary angle closure glaucoma.

ABSTRACT.Purpose: To evaluate the distribution of anterior chamber angle (ACA) parameters and to assess association of these parameters with age in Asian subjects. Methods: Four hundred and thirty-nine consecutive Korean subjects aged from 30 to 89 were enrolled from a university clinic. All participants were scanned using anterior segment optical coherence tomography (AS-OCT, Visante, version 2.0). We measured ACA parameters such as anterior chamber depth (ACD), angle opening distance at 500 and 750 lm (AOD 500,750 ), angle recess area at 500 and 750 lm (ARA 500,750 ), trabecular iris space area at 500 and 750 lm (TISA 500,750 ), and determined age-related changes in these parameters with use of a linear mixed effect model that adjusted for gender, axial length, intraocular pressure, and keratometry data. Slopes of ACA parameters as a function of age were determined. For various AS-OCT parameters, the normalized slope was calculated by dividing the slope by the mean value. Results: All analysed ACA parameters decreased with age in both nasal and temporal quadrants. Axial length and keratometry data were significant covariates for ACA changes. The slopes of ACD were )0.02396 mm ⁄ year, AOD 500 , ARA 500 , and TISA 500 measured at the temporal angle were )0.00634 mm ⁄ year, )0.0019 mm 2 ⁄ year, and )0.00177 mm 2 ⁄ year, respectively. There was no age-dependent difference in central corneal thickness (p value; 0.4597) Based on the normalized slopes, the AOD showed the steepest slope at both temporal and nasal sectors. Conclusion: All ACA parameters assessed by AS-OCT, which accounted for other ocular biometric parameters, showed significant negative slopes with increasing age. These results should be considered when assessing changes in the anterior chamber over time.