Abstract
Abstract: :
Purpose: To determine tear film parameters associated with KCS in patients with chronic blepharitis. Methods: Twenty-four patients with various forms of chronic blepharitis were classified into hyper-evaporative, hypo-secretory, and combined mechanism keratoconjunctivitis sicca groupings based on clinical appearance, e.g. presence or absence of signs of MGD. The tear film parameters assessed were tear turnover, tear volume, tear flow, Schirmer test, ocular evaporation, and meibomian gland dropout. The effect of age on the various tear parameters was determined without subgrouping. Results: Hyper-evaporative, hypo-secretory, and combined mechanism KCS were found respectively to have tear turnover of 0.19, 0.31, 0.11, tear volume of 6.21, 3.06, 3.16, tear flow of 0.62, 0.53, 0.26, Schirmer test of 18.02, 8.71, 16.60, ocular evaporation of 4.87, 5.57, 5.41, and meibomian gland dropout of 43.69, 31.92, 36.68. There are large differences between the hyper-evaporative and hypo-secretory group values for tear volume, tear turnover, meibomian gland dropout, and Schirmer test with the Schirmer value being the only one reaching statistical significance (p = 0.003). Increased age was correlated with decreasing tear flow only (p = 0.01). Conclusions: Remarkably, the Schirmer test was the most positively correlated test with the clinical impression of type of KCS with the hypo-secretory group having the lowest value. The clinical impression of hyper-evaporative KCS based on difficulty of expressability of meibomian secretions and their turbidity correlated with meibomian gland dropout but not excessive tear evaporation. The role of MGD in KCS requires further investigation. Decreasing tear flow with age was not an unexpected finding.