Intermittent exotropia: relation between age and surgical outcome: a change-point analysis.

PURPOSE: To study the relationship between age and response to surgery in patients with intermittent exotropia and to identify change points in response to surgery. METHODS: A retrospective analysis was conducted on 311 patients with intermittent exotropia who had bilateral lateral rectus recession using standard tables with minimum follow-up of 6 months. Data were analyzed using the change-point analysis software to identify cutoff points. A prospective pilot study was then performed on 171 consecutive patients with intermittent exotropia with the same clinical characteristics, in whom amount of recession was modified according to the identified cutoff points. In angles with two change points, 1-mm recession was reduced from patients younger than the lower change point and 1.5-mm recession was added to those older than the upper change point. In angles with one change point, 1.5-mm recession was added to those older than the change point. Satisfactory alignment was defined as esophoria/tropia ≤ 5Δ to exophoria/tropia ≤ 8Δ. RESULTS: There was a negative correlation (P<0.01) between response to surgery and age at surgery for all angles. In younger patients (<7 years) in whom surgical dose was reduced, there was no significant change in success rate (77%), compared with those who had surgery using standard tables (75%). In older patients (>12 years) in whom surgical dose was increased, there was a statistically significant increase in success rate (80% vs 41%). CONCLUSIONS: Modifying the surgical dose according to age can improve the success in patients with intermittent exotropia.

Polypropylene vs silicone Ahmed valve with adjunctive mitomycin C in paediatric age group: a prospective controlled study.

PURPOSE: To compare the results of silicone and polypropylene Ahmed glaucoma valves (AGV) implanted during the first 10 years of life. METHODS: A prospective study was performed on 50 eyes of 33 patients with paediatric glaucoma. Eyes were matched to either polypropylene or silicone AGV. In eyes with bilateral glaucoma, one eye was implanted with polypropylene and the other eye was implanted with silicone AGV. RESULTS: Fifty eyes of 33 children were reviewed. Twenty five eyes received a polypropylene valve, and 25 eyes received a silicone valve. Eyes implanted with silicone valves achieved a significantly lower intraocular pressure (IOP) compared with the polypropylene group at 6 months, 1 year, and 2 years postoperatively. The average survival time was significantly longer (P=0.001 by the log-rank test) for the silicone group than for the polypropylene group and the cumulative probability of survival by the log-rank test at the end of the second year was 80% (SE: 8.0, 95% confidence interval (CI): 64-96%) in the silicone group and 56% (SE: 9.8, 95% CI: 40-90%) in the polypropylene group. The difference in the number of postoperative interventions and complications between both groups was statistically insignificant. CONCLUSION: Silicone AGVs can achieve better IOP control, and longer survival with less antiglaucoma drops compared with polypropylene valves in children younger than 10 years.