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Editors Selection IGR 18-3
Medical Treatment: Round-the-clock effects of IOP lowering eyedrops
Comment by Franz Grehn on:
71499 Efficacy and safety of preoperative IOP reduction using a preservative-free fixed combination of dorzolamide/timolol eye drops versus oral acetazolamide and dexamethasone eye drops and assessment of the clinical outcome of trabeculectomy in glaucoma, Lorenz K; Wasielica-Poslednik J; Bell K et al., PLoS ONE, 2017; 12: e0171636
The major long-term challenge of filtration surgery is excessive wound healing and failure by scar formation of the new outflow route. The wound healing process is significantly influenced by the amount of conjunctival inflammation resulting from long-term antiglaucomatous topical medication. Most topical antiglaucoma medications and preservatives induce inflammation. Preoperative reduction of inflammation is a pivotal step to better postoperative bleb development. Therefore, many surgeons use regimens to quiet inflammation preoperatively.
In a subgroup of severe preoperative inflammation from medication, the addition of preoperative steroids may be still be considered
The present study compares two different preoperative regimens, (1) dorzolamide/timolol preservative free combination versus (2) acetazolamide/dexamethasone as pretreatment four weeks prior to surgery after discontinuation of their individual preoperative topical medication. The two arms of this randomized prospective study included 30 and 32 patients, respectively. IOP decrease after surgery at three months follow-up was used as the primary outcome measure. Secondary outcomes were the number of 5-FU injection needed, needlings, suture lysis, hypotension rate, visual acuity, and bleb morphology. The adverse events were studied with the vision-related NEI VFQ25 test.
Regarding IOP change no differences or inferiority could be found with the dorzolamide/ timolol preservative free regimen at three months (IOP decrease -8.12 mmHg versus -8.30 mmHg) and at six months (9.13 mmHg versus -9.06 mmHg). All secondary parameters were also not significantly different. The NEI VFQ 25 test battery showed increased reporting of AE's in the azectazolamide/dexamethasone group.
The results demonstrate that reducing the preoperative medication to either a fixed combination of unpreserved dorzolamide/timolol or treating preoperative IOP with oral acetazolamide plus topical steroids is equally effective. However, the role of preoperative topical steroids for suppression of inflammation should be further investigated as result might also depend on the severity of preoperative inflammation which was not quantified in this study. Although the initial inflammation was balanced by randomization, in a subgroup of severe preoperative inflammation from medication, the addition of preoperative steroids may be still be considered and their usefulness should be tested in a subsequent study as proposed by the authors.
