Health-Related Quality of Life in two treatment pathways for primary open angle glaucoma and ocular hypertension: a randomised controlled trial of initial selective laser trabeculoplasty versus conventional medical therapy

This is an unmasked pragmatic randomised controlled trial using a ‘Treat in Pursuit of Control' design to reflect clinical practice in previously untreated patients with open angle glaucoma (OAG) or ocular hypertension needing (OHT) intra-ocular pressure (IOP) reduction. It compares health-related quality of life at 3 years with either initial selective laser trabeculoplasty (SLT), followed by conventional medical therapy as required (‘Laser 1st’) or medical therapy without laser (‘Medicine-1st’), while measuring incremental cost and cost-effectiveness of each pathway. A NICE-guideline-based control Target IOP is set for each participant who then proceeds through stepped increments of treatment (up to and including surgery) until the predetermined target is reached. SLT is a YAG laser technology applied to the ocular trabecular meshwork (aqueous humor outflow site). It is reported as being both more effective and safer than existing lasers and that treatments can be safely repeated [McIlrait 2006, Nagar 2005]. SLT lowers intra-ocular pressure by 20% in 80% of patients [Juzych 2004]. Thus the need for topical medications can be delayed, possibly for several years and it may reduce the amount of subsequent medical treatment required and delay the need for surgery. SLT delivered in an outpatient setting using topical anaesthesia is quick and pain-free. Adherence to drops is well known to be poor with up to 75% of patients failing to comply [Nordstrom 2005]. Drops can have severe adverse effects and are associated with reduced HRQL [Balkrishnan 2003]. A single laser treatment may be a preferable option to daily use of eye-drops. Models suggest SLT is still cost saving [Cantor 2008, Taylor 2008]. Existing studies are short and of limited generalisability: we have chosen the 3 year follow-up to look for superiority of HRQL (and examine cost) at the time when the majority of patients receiving SLT will have had a repeat treatment, if required.