Glaucoma surgery with or without adjunctive antiproliferatives in normal tension glaucoma: 2 Visual field progression

Background-Reduction of intraocular pressure by 20-30% with glaucoma draina ge surgery slows disease progression in normal tension glaucoma (NTG). It i s not clear whether adjunctive antiproliferative agents are necessary or sa fe in eyes at low risk for scarring. Method-61 eyes of 61 white patients with NTG who had undergone a primary gu arded fistulising procedure were reviewed. 20 eyes had no antiproliferative s (nil), 29 had peroperative 5-fluorouracil (5-FU), and 12 had peroperative mitomycin C ((MMC). Pointwise linear regression analysis (PROGRESSOR for W indows software) was applied to their visual field series starting with the first visual field following surgery and adding subsequent visual fields o ne at a time. Progression of visual field loss was defined as the appearanc e of a regression slope 1 dB per year or more with a significance of p<0.01 at one or more visual field locations which remained consistent with the a ddition of two of three successive visual fields. Time updated covariate an alysis was used to determine the relation between variables that changed wi th time, such as IOP, and the risk of progression. Results-The median percentage IOP reduction was 24.4 for the nil group, 38. 0 for the 5-FU group, and 47.5 for the MMC group (p=0.001). There was a sta tistically significant relation between percentage change in IOP and risk o f visual field progression in the subsequent 6 month period for all patient s analysed as one group, hazard ratio = -0.021 (p=0.002). There was a stati stically significantly increase in the risk of visual field progression for the MMC group compared with the 5-FU group, hazard ratio = 1.51 (p=0.02). Conclusion-In NTG patients, the IOP reduction produced by drainage surgery reduces the risk that visual field progression may be reduced after drainag e surgery; this is related to the level of IOP reduction. The percentage dr op in IOP during a given time is related to the risk of subsequent visual f ield progression. However, the use of MMC is associated with a greater risk of visual field progression despite a greater fall in IOP. This visual fie ld deterioration may be related to the functional loss produced by late pos toperative complications which have been reported at a higher rate in this group. The use of adjunctive perioperative 5-FU should maintain a suitable target IOP with preservation of visual function without the additional comp lications and associated visual deterioration seen with adjunctive MMC.