Prophylactic Use of Brimonidine or Apraclonidine for Intraocular Pressure Elevation following Laser Iridotomy

PURPOSE: The purpose of this study was to evaluate and compare the prophylactic effect of brimonidine 0.2% and apraclonidine 0.5% in preventing intraocular pressure(IOP) elevation in patients undergoing laser iridotomy. METHODS: The 24-hour, placebo-controlled, randomized, clinical trial was conducted to determine the efficacy of brimonidine 0.2% and apraclonidine 0.5% in controlling IOP after combined argon and Nd:YAG laser peripheral iridotomy. The 110 eyes(56 eyes with angle closure glaucoma, 54 eyes with narrow occludable angle) were randomized to receive brimonidine 0.2%, apraclonidine 0.5% or artificial tear(as placebo) 20 minutes before the procedure. IOP was measured before and 1, 2, and 24 hours after the procedure by masked observer using Goldmann applanation tonometry. The difference between preoperative(baseline) IOP and the highest postoperative IOP was recorded as the maximum IOP rise. RESULTS: The mean of maximum IOP rise was 1.1+/-5.6 mmHg in the brimonidine group, 1.0+/-2.9 mmHg in the apraclonidine group and 4.7+/-7.6 mmHg in the placebo group. There was statistically significant decrease in IOP in both drug groups compared to the placebo group(p0.05). CONCLUSIONS: Both brimonidine 0.2% and apraclonidine 0.5% were significantly effective in preventing IOP spike following laser iridotomy procedure. There was a tendency toward less efficacy with brimonidine 0.2% compared to apraclonidine 0.5%, but this was statistically insignificant.

Effects of Mitomycin C on Cultured Rabbit Osteoblasts

PURPOSE: To evaluate the effect of mitomycin C (MMC) on osteotomy site as an adjunctive therapeutic agent during dacryocystorhinostomy, the effect of MMC on cultured rabbit osteoblasts was tested. METHODS: Cultured osteoblasts which was obtained from the iliac crest of rabbits, were treated with MMC (0.2 mg/ml) for 5 or 30 minutes, washed and changed with fresh osteogenic media (Opti-MEM), and then cultured for 24 hours. To observe the effect of MMC dose dependency on cultured osteoblasts, four different concentrations of MMC (0.2 mg/ml, 0.02 mg/ml, 0.002 mg/ml, 0.0002 mg/ml) were applied into the cells and cultured for 24 hours. The effect of fibroblast growth factor (FGF) and transforming growth factor-beta(TGF-beta) on the MMC-treated cells was evaluated. In control group, osteoblasts were cultured in osteogenic media without exposure of MMC for 24 hours. Cell viability was measured using trypan blue staining method. RESULTS: As compared with control group, the growth of osteoblasts was inhibited by MMC (0.2 mg/ml) treatment, 30-minute treatment group demonstrated marked suppression twice as much as 5-minute treatment group. Growth rate of 0.2 mg/ml MMC-treated cells was highly suppressed to 7.7% of control and 0.02 mg/ml MMC-treated cells was inhibited to 15.4% in number. Growth rate of 0.002 mg/ml, 0.0002 mg/ml MMC-treated cells was diminished to 53.8%, 84.6% in number, respectively. Both growth factors had promotive effect on the growth of osteoblasts in 0.002 mg/ml MMC-treated cells, especially in TGF-beta. CONCLUSION: Osteoblasts which were treated for longer time and with higher concentration of MMC showed more severe suppression in growth rate. These results suggest that MMC could have some therapeutic effect on osteotomy site of dacryocystorhinostomy.

Change of Postoperative Distance Stereoacuity in Intermittent Exotropic Patients

To determine whether distance stereoacuity improved following strabismus surgery in patients with intermittent exotropia, we tested distance stereoacuity of 107 patients preoperatively and postoperatively using the Mentor B-VAT IIVideo Acuity Tester. Following successful surgical alignment there was significant improvement of postoperative distance stereoacuity in binocular vision contour circles[BVC]and binocular vision random dot E[BVRDE]test[p<0.05 ]. Based on BVC testing, performance improved 45.8%of the patients after surgery, remained unchanged in 43.0%, and decreased in 11.2%. Based on BVRDE testing, performance improved 29.9%of the patients after surgery, remained unchanged in 66.4%, and decreased in 3.7%. But improvement of postoperative distance stereoacuity was not related statistically to age, operative methods, suppression, and preoperative size of deviation. From the results of this study, it is concluded that the BVC test is a useful test for assessing control in intermittent exotropic patients. Distance stereoacuity improved after successful operation, thus distance stereoacuity test may be helpful in evaluation of preoperative and postoperative intermittent exotropia control.