Sir,

We read with interest the findings presented by the authors.1

In May 2013, we performed a prospective audit in our unit to assess current prescribing trends in our glaucoma clinics. Our results (presented at RCOphth 2014) are consistent with national trends.

Of the 100 continuous patients seen in our unit, 10 patients were switched within the prostaglandin analogues class with improved efficacy and tolerability. Fifty percent of these patients were switched from latanoprost/xalatan to bimatoprost.

Switching within glaucoma medication class is part of our glaucoma unit protocol. There was a small crossover study by Gandolfi and Cimino,2 which showed IOP-lowering effect in 13 out of 15 latanoprost non-responders who switched to bimatoprost. There have also been small studies3, 4 and anecdotal reports5 regarding issues with generic latanoprost bottles due to the different manufacturers. These reasons may account for the move away from generic latanoprost to bimatoprost.

The 2013 prescribing cost analysis data have seen an inclusion of preservative-free bimatoprost 0.03% (Lumigan 0.03% unit dose). This is an increasingly popular option in our unit for patients who have reported side effects to other drugs.

It would be interesting to observe future trends especially with the growing range of preservative-free glaucoma products in the market.