Tear fluid and Complement activation products in tears after ocular surgery.

Purpose: To investigate changes in the tear film complement activation products (CAPs) and ocular surface after vitrectomy combined with cataract surgery. Methods Forty-three patients (23 women; median age, 69 years) were enrolled in this prospective study and underwent phacoemulsification and vitrectomy. We measured Schirmer's test (ST) and CAPs in the tears at baseline, 4 days and 1 month after the surgery. Tears were collected in microtubes. The CAPs in the tear fluid were analyzed by cytometric bead array. Results A negative correlation was found between the ST and C3a (r 2 = -0.37, P  = 0.0015) at baseline. The median ST (8.5 mm) at baseline increased to 16 mm at 4days ( P  < 0.001) and 10 mm at 1 month ( P  = 0.44). The C3a levels (1202 pg/ml) at baseline increased to 2753 pg/ml at 4 days ( P  < 0.001), and 1763 pg/ml at 1month ( P  = 0.049). The C4a levels (476 pg/ml) at baseline increased to 880 pg/ml at 4days ( P  < 0.001), and 657 pg/ml at 1 month ( P  = 0.013). The C5a levels (22.6 pg/ml) at baseline increased to 470.9 pg/ml at 4 days ( P   10 mm, n = 21) based on the preoperative ST values. At 1 month postoperatively, the C3a levels was 2194 pg/ml in the preoperative short ST group and 1391 pg/ml in the long ST group, with significantly higher C3a concentrations in the short ST group ( P  < 0.001). Conclusions The CAPs levels in tears increased after vitrectomy combined with cataract surgery. A preoperative deficit in tear secretion might induce prolonged complement activation and delayed recovery of ocular surface parameters postoperatively.