We want to thank Drs Martinez and Sanchez for taking the time and effort to respond to our recent editorial. We are very grateful for their agreement with us that long-term prospective multicentre studies are needed to evaluate the impact of ocular blood flow in the pathogenesis and treatment of glaucoma. In addition, we are in heartfelt agreement with them, as we expressed in our editorial, that evidence does exist that blood flow is altered in glaucoma and is suggestive of a pathogenetic role.1 We also agreed in the editorial that a variety of methods are being used to evaluate blood flow, and these techniques certainly have improved over the last decade and a half.

I would also like to thank Drs Martinez and Sanchez for calling attention to the readers of BJO to their fine article in Acta Ophthalmologica2 detailing their prospective analysis of blood flow in glaucoma. They are to be congratulated on their work. Unfortunately, in an editorial, space is limited, and not all research could be highlighted to the extent that we would have desired.

The article mentioned by Drs Martinez and Sanchez is an elegant early step in attempting to prospectively determine blood-flow-based risk factors for progression over the mid-term in patients with glaucoma. In the 49 patients evaluated by the authors (23 progressed and 26 non-progressed over 3 years) differences in resistivity index in the ophthalmic and short posterior arteries, as measured with colour Doppler, predicted approximately 80–90% of patients who ultimately progressed or remained stable.2

The work of Drs Martinez and Sanchez, and their response letter to our editorial, are a welcomed reminder that the ophthalmic community needs to progress to a more definitive evaluation of blood flow in glaucoma to determine if indeed disturbed ocular haemodynamics is related to the pathogenesis of glaucoma and if improving this parameter improves long-term visual outcomes. By doing so, we hope that in the future, our patients, who may be at risk for progression because of systemic or ocular vascular disease, may be more specifically and adequately treated.