Eyes with advanced glaucoma are required to have very low intraocular pressures (IOP) for protection against visual field loss.1 Although trabeculectomy has largely been considered the most effective surgery for reducing pressure, a major concern for clinicians has been the perceived high risk of complications associated with this procedure. No specific guidance currently exists for treatment of patients with advanced glaucoma at diagnosis. In some countries, such as the UK, guidelines suggest that patients presenting with advanced disease should be offered trabeculectomy as a primary intervention; however, they cite poor evidence to support this recommendation.
King et al. carried out a multi-center (27 secondary glaucoma care centers in the UK), randomized, controlled trial to compare primary medical management (n = 226) against primary mitomycin C augmented trabeculectomy (n = 227) for patients presenting with previously untreated advanced open-angle glaucoma. The primary outcome was vision-specific quality of life measured with Visual Function Questionnaire-25 (VFQ-25), while clinical effectiveness and safety were also compared. At 24 months, no significant differences were found in the mean VFQ-25 scores in the trabeculectomy (85.4) and medical arms (84.5) (P = 0.38). While mean IOP was 2.8 mmHg lower in trabeculectomy 12.4 ± 4.7 arm compared to medical management 15.1 ± 4.8 mmHg (P < 0.001), frequency of side effects were comparable and serious side effects were rare.
The strengths of the study include the inclusion of multiple centers and multiple surgeons undertaking standard trabeculectomy as well as the use of available topical medications. In addition, this pragmatic approach attempted to replicate current clinical practice in the management of advanced glaucoma as closely as possible. Moreover, maintaining patients' quality of life is the most important outcome of glaucoma management, which was used as the primary outcome in this trial.
This clinical trial suggested that primary trabeculectomy had similar quality of life and safety outcomes compared with primary medical management.
Two-year follow-up assessments are inadequate to draw treatment conclusions and these outcomes might not support altering current treatment approaches to open-angle glaucoma
While the data provided in this review are promising, longer-term findings would be essential to generalize these findings. Two-year follow-up assessments are inadequate to draw treatment conclusions and these outcomes might not support altering current treatment approaches to open-angle glaucoma. For example, in the Collaborative Initial Glaucoma Treatment Study (CIGTS),2 although both initial medical or initial surgical therapy resulted in about the same visual field outcome after up to three years of follow-up, the proportion of eyes that had substantial VF worsening (≥ 3 dB) was 1.6 times greater in the medication arm compared to the surgical arm. Information about IOP fluctuation is also important, as the extent of IOP variation that occurs during treatment may be a more important contributor to the risk of VF progression than mean IOP or other summary IOP measures especially in lower IOPs.3 Lastly, 17% of eyes in the medication arm underwent trabeculectomy during the follow-up. One may also consider that trabeculectomy outcome is better on naive eyes compared to trabeculectomy on eyes already on multiple topical IOP-lowering medications.4