Sir,

The article by Shah et al (Eye 15; 616–620) does a service to ophthalmologists by drawing our attention to the existence of this distressing visual symptom in the eyes of young adults with advanced glaucoma. I would concur that the simplest explanation would be that of a circulatory ‘steal’. It is worth remembering that the phenomenon is not restricted to this age group, and is probably to be found more frequently among the elderly. In this older age group, not only exercise (of such a trivial nature as climbing stairs) but also hot baths have been reported to me as causing the same symptom. Avoidance of the causative action, aspirin, and stricter IOP control appear to be the safest remedies on offer to reduce the frequency of attacks.