Objective To observe the changes of tear film stability,goblet cell and mucin 5AC expression in conjunctivochalasis patients,and explore the mechanism of conjunctivochalasis.Methods Conjunctivochalasis patients (30 cases) and single age-related cataract patients (15 cases) were collected as conjunctivochalasis group and normal control group.Eye symptom assessment (OSDI score),tear break-up time (BUT),Schirmer Ⅰ test,tear fern crystallization tests were performed for all the selected persons.Conjunctival rescent-shaped resections were made for all the conjunctivochalasis patients.Conjunctival tissue samples were stained by HE staining,AB staining,mucin 5AC immunohistochemical staining from the conjunctivochalasis group and norral control group respectively,and then statistical analysis was made.Results The OSDI score in the conjunctivochalasis group (37.80 ± 8.94) was significantly higher than that in the normal control group (11.40 ±4.08) (P ＜0.01).BUT in the conjunctivochalasis group (6.70 ± 2.76) s was significantly lower than that in the normal control group (13.67 ± 3.48) s (P ＜ 0.01).Schirmer Ⅰ test in the conjunctivochalasis group (6.23 ± 3.13) mum was significantly lower than the normal control group (13.40 ± 3.74)mm (P ＜ 0.01).Tear ferbing crystallization of the conjunctivochalasis group was decreased significantly compared with the normal control group (x2 =14.309,P =0.003).Light microscopic showed that conjunctival thickness was thinned,collagen fibers were less,elastic fiber was reduced,the lamina propria and interstitial were congestion and edema,the number of goblet cells was significantly reduced,and the positive staining of mucin 5AC staining was significantly lower in the conjunctivochalasis group than in normal control group (x2 =9.499,P =0.023).Conclusion For patients with conjunctivochalasis,the tear film function is affected,goblet cells are decreased,tear fern crystallization is decreased,mucin 5AC content is decreased,which finally leads the excessive conjunctival relaxation and abnormal ocular surface and tear.