Analysis Of The Relationship Between Tear Film, Epithelial Cell Stability And The Mechanical Injury Of Ocular Surface

The maintenance of the health of the ocular surface is a complex process and needs the coordinating role of corneal and conjunctival epithelium and tear film. Entropion or trichiasis are common diseases of the eyelids, and may result in severe mechanical trauma of ocular surface. The inverted eyelashes in patients can lead to changes of structure and function of corneal and conjunctival epithelial cell and the stability of tear film besides photophobia, epiphora, foreign body sensation or eyelid spasm and other symptoms, or even, corneal epithelial exfoliation is caused by cilia friction,when secondary infection happened,it may become corneal ulcers, the prognosis is a surviving keratoleukoma or neovascularization, and corneal transparency lose and lead to severe visual impairment, all of them affect seriously the healthy and stability.of ocular micro-environment.To investigate the relationship between the mechanical injury of ocular surface and tear film and epithelial cell stability, and the situation of improvement of ocular microenvironment postoperatively.106 eyes of 60 inpatients from January to December in 2009 in Ophthalmology DEPARTMENT of the second hospital of Jilin University were enrolled in this randomized study,and were divided into three groups according to the pathogenesis: congenital entropion group (n= 41), senile entropion group (n= 45)and cicatricial entropion group (n= 20).A11 enrolled patients in this study were examined preoperatively,1 week and 1 month postoperatively by Schirmer's I test (STI), tear film break up time(BUT), Cornea fluorescein staining (CFS) and Conjunctival impression cytology (CIC) (according to Nelson rating). We compared preoperative functional status of the tear film, goblet cell density and degree of squamous metaplasia of conjunctival epithelial cells with the postoperative to investigate the situation of improvement of ocular microenvironment. All data were recorded as!±S, the present results were analysed by SPSS software version 17.0. Probalility(P) values less than 0.05 were considered to be statistically significantly.The research results show that:(1) Compared with the preoperative, there was no significant changes in tear secretion of three groups of patients with entropion or trichiasis at 1 week and 1 month postoperatively (P> 0.05). (2) The postoperative break up time (BUT) of three groups of patients was much longer than the preoperative,there was statistical significance (P< 0.05). Observing the experimental results of 1 week and 1 month postoperatively, the break up time of senile entropion group (8.95±3.75s; 9.43±2.67s) and congenital entropion group (9.20±7.35s; 10.01±3.32s) was longer compared with cicatricial entropion group (6.02±3.43s; 6.34±6.86s). (3) The results of corneal staining of three groups of patients preoperatively and postoperatively show that, cornea fluorescein staining reduce or even disappear, all of corneal fluorescein staining score decrease, and most of patients'cornea restore smoothly and transparently after surgical correction, there was statistical significance (P < 0.05) (4) The postoperative squamous metaplasia of patients with congenital and senile entropion decreased a little at a time, and the level of goblet cell density also increased significantly,there were significant differences compared with preoperative squamous metaplasia and goblet cell density (P< 0.05). The postoperative squamous metaplasia of patients with cicatricial entropion decreased compared with the preoperative (P< 0.05), However, there was no significant increase in goblet cell density (P> 0.05)Analysis of these results,we can obtain the following conclusions:The persistent mechanical trauma by cilia in patients with entropion or trichiasis can induce conjunctival squamous metaplasia, reduction in the number of goblet cells, damage of the integrity of corneal epithelium and decrease of tear film stability; However, these conjunctival changes can be reversed by surgical correction, which suggests that it's necessary for patients with entropion or trichiasis of surgical correction timely; Relative to cicatricial entropion, the recovery of function of ocular surface after surgical correction is better for congenital and senile entropion.In conclusion, the coordinating role of corneal and conjunctival epithelium and tear film is the basis of the maintenance of the health of the ocular surface. Tear film is corneal barrier and attached to corneal and conjunctival epithelium, incomplete tear film may cause damage to corneal and conjunctival epithelium, while corneal and conjunctival epithelial injury changes the composition of tear, and increases the difficulty of the tear film adhesion at the same time. The two sides are complementary and influence each other. The entropion or trichiasis breaks the balance of the normal ocular.therefore, according to different pathogenesis of the entropion or trichiasis, we select corresponding surgical procedures to prevent the mechanical friction of the cornea and conjunctiva surface, restore the function of ocular surface epithelial cell gradually, promote the secretion of mucin, eliminate inflammatory response, and improve the stability and integrity of the tear film, and form a virtuous circle at last. Hence, Ocular micro-environment is improved effectively and achieve the state of health.