Sir,

We would like to thank Svasti-Salee et al for their response to our letter entitled ‘Cotton-wool spots and migraine: a case series of three patients’. The authors give a long list of all possible diagnoses that may present with cotton-wool spots (CWS). We would agree that patients with CWS should be appropriately investigated.

Indeed, all three of our patients had blood pressure measurement, routine serum biochemistry, and haematology tests (including inflammatory markers) on presentation. Furthermore, fundus fluorescein angiogram (FFA), optical coherence tomography (OCT), and Goldmann visual field testing were performed in each case. The patients, who were all below the age of 50, were then followed-up initially within 1 month, then around 2 months following this, then finally at 6 months, at which point symptoms and signs had completely resolved. All tests carried out were normal, other than the presence of an isolated CWS on the FFA and OCT images. We were unable to give all this detail due to the word count stipulation of this article.

We would also agree with Svasti-Salee et al that our observation, that isolated CWS and migraine could be linked, is speculation. Migraine is a complex disorder and, as the authors point out, the understanding of its pathophysiology is evolving. However, we would suggest that it seems likely that there is an association based on the evidence that we have cited and our observations in these three young, healthy patients.

Svasti-Salee et al appear to have misinterpreted the message of our article. We would certainly advocate appropriate investigation and follow-up of patients with CWS. The risk of an associated life or sight threatening disease becomes higher with the presence of any concerning clinical features such as increasing age, evidence of vascular disease elsewhere in the retina, or elsewhere in the body.