Tear Function Changes Postoperatively In Patients With Pterygium

Background and ObjectivePterygium is a common external eye disease affecting people around the world, and its prevalence increases with proximity to the equator. It usually grows from the nasal side, affecting both eyes. Clinical manifestations of pterygium can include increased astigmatism, decreased visual acuity and poor cosmesis. Pterygium is an elastotic degeneration of the conjunctiva that produces fibrovascular tissue, which invades the superficial cornea. It destroys Bowman's layer through fibrovascular ingrowth. The main histopathologic change in primary pterygium is elastodysplasia and elastodystrophy of the subepithelial connective tissue. Pterygium's origin, pathogenesis and recurrence rate are all mysteries. Thetreatment of pterygium has been traditionally reported to be surgical excision. Until recently, surgical treatment usually consisted of simple pterygium resection leaving a bare sclera;or combined with limbal-conjunctival autograft transplantation, or amniotic membrane transplantation, or lamallar corneal transplantation. Adjunctive therapy include application of antifibrotic agents such as mitomycin C, 5-Fu uracil and β-irradiation. Reports about tear hyposecretion in patients with pterygium have led to the theory that dry eye could be a causative factor in the pathogenesis of this disease. But there were few studies concerning the role of tear film in the pathogenesis of pterygium. In recent years, Pterygium excision combined with limbal-conjunctival autograft transplantation has become increasing accepted as a method likely to prevent pterygium recurrence. It's not clear whether this method can result in changes of tear function in patients with pterygium. So we evaluated the tear function tests in patients with pterygium.Materials and Methods30 eyes of 30 patients with unilateral pterygium which were operated in Tai Zhou Central Hospital between September 2005 and February 2007, were entered in the study. Schirmer Ⅰ test, tear break up time (BUT) and mucus fern test(MFT) were evaluated in the patients before and after pterygium excision combined with limbal-conjunctivalautograft transplantation. Data were processed using SPSS 12.0 software. All the probability level set at 5% for statistical significance.ResultsComparing with the opposite healthy eyes, the results of BUT , MFT were significant different, there were no significant difference in the results of Schirmer Ⅰ test. The results of BUT,MFT were significant different before and after surgery(4 weeks later), there was no significant difference in Schirmer Ⅰ test. When compared with the BUT before surgery (9. 89 ±3. 93) s, BUT prolonged significantly 4 weeks (12.78 ± 4.12) s and 8 weeks (14.27 ± 3.80) s after surgery (Oneway ANOVA P<0.05) ; Before surgery, only 46. 7% of the patients showed normal crystallization in MFT, and the ratio increased significantly to 80. 0% 4 weeks after surgery and 86. 7% 8 weeks after surgery (x~2 test P <0.05 ).ConclusionTear functions were abnormal in patients with pterygium. Pterygium can affect the results of BUT and MFT. Pterygium excision combined with limbal-conjunctival autograft transplantation can partly restore the tear functions into normal state in patients with pterygium.