Lee YP, et al. - In this investigation, researchers quantified the amounts of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2 and bone morphogenetic protein (BMP)-4 in medial rectus muscle (MR) tissue obtained from intermittent exotropia (IXT) patients and studied the association between each protein amount and the clinical characteristics of IXT including angles of deviation, age at surgery, duration of IXT and postoperative recurrence. The protein amounts were measured in MR collected during surgery for 78 IXT patients using enzyme-linked immunosorbent assay. Data reported that the mean amount of MMP-2 per mm of resected MR was 0.86 ng, of MMP-9, 2.72 ng, of TIMP-1, 1.99 ng, of TIMP-2, 0.92 ng and of BMP-4, 0.82 pg. TIMP-1 displayed a negative association with the angle of deviation at distance and at near. MMPs and BMP-4 tended to increase in IXT patients and TIMPs tended to decrease with increasing angle of deviation, increased age in surgery, and longer duration of IXT.