Non-enhanced trabeculectomy by non-glaucoma specialists: are results related to risk factors for failure?

Purpose To determine the 1 year success rate of non-enhanced trabeculectomy under the care of non-glaucoma specialists and the effects of risk factors on the surgical outcome as measured by intraocular pressure (IOP) control. Methods A retrospective study of 167 patients undergoing trabeculectomy was performed. One hundred and four cases were performed in a teaching hospita l and 63 in a district general hospital (DGH). Non-glaucoma specialists per formed all the operations, enhanced trabeculectomy with antimetabolites bei ng excluded. Information was recorded from a retrospective review of case n otes, and post-operative IOPs at 12 months follow-up were analysed. Risk fa ctors for failure were defined as: (1) age less than 40 years old, (2) blac k race, (3) diabetes mellitus, (4) miotic therapy greater than or equal to 18 months, (5) sympathomimetic therapy greater than or equal to 6 months, ( 6) pseudophakia or aphakia, (7) previous failed filtration procedure, (8) a rgon laser trabeculoplasty, (9) previous ocular surgery and (10) high-risk glaucoma (angle recession glaucoma, uveitic glaucoma and neovascular glauco ma). A success was defined to be a post-operative IOP at 1 year of less tha n 21 mmHg and at least 20% less than the presenting IOP on no medication. Results The overall success rate was 139 of 167 (83.2%). Eighty-seven of 10 4 eyes (83.7%) were classified as a success in the teaching hospital group and 52 of 63 (82.5%) were classified as a success in the DGH group. There w as no significant difference in the number of risk factors between the succ ess and failure groups. Eyes with two or more risk factors had significantl y higher IOPs at 1 year when compared with eyes with 0 or 1 risk factor (me an +/- SD: 17.4 +/- 6.34 mmHg vs 14.2 +/- 5.0 mmHg, p = 0.022). When only ' successful eyes' were analysed, those with two or more risk factors still h ad significantly higher IOPs at 1 year (mean +/- SD: 15.0 +/- 3.0 mmHg vs 1 2.8 +/- 3.9 mmHg, p = 0.046). There were significantly fewer eyes in the tw o or more risk factor group with IOPs < 16 mmHg at 1 year (26.1% vs 60.4%, p = 0.021). Conclusions Eyes at relatively low risk for failure operated upon by non-gl aucoma specialists appeared to have success rates similar to previously pub lished series. Eyes with two or more risk factors for failure have higher I OPs at 1 year in non-enchanced trabeculectomy. Adjunctive anti-scarring age nts may be considered for these patients when filtration surgery is schedul ed.