Phosphodiesterase Inhibitors in Glaucoma Study (PhiGS)
Status:
Suspended
Trial end date:
2022-10-30
Target enrollment:
Participant gender:
Summary
It is commonly known that high eye pressure is associated with glaucoma. However, there is
also a theory that poor circulation to the eye is a contributing factor. Therefore, if we can
increase the flow of blood to the eye, we may be able to stop people losing vision from this
disease.
Phosphodiesterase inhibitors (for example sildenafil, tadalafil, Viagra®, Cialis®) are drugs
used to improve blood flow to certain parts of the body. They are commonly used on an ad-hoc
basis to treat erectile dysfunction, in addition to problems with blood circulation to the
lungs, fingers and toes.
The majority of previous work in this field has been completed using insensitive, poorly
reproducible techniques such as colour doppler ultrasound. Since then, a new imaging modality
able to image blood flow in blood vessels without the need for the injection of contrast has
entered clinical use.
This initial pilot study is designed as a proof-of-concept study to investigate whether we
can measure detectable changes in the blood flow to the retina and choroid at the back of the
eye following ingestion of a phosphodiesterase inhibitor medication by healthy and
glaucomatous volunteers already taking this medication for erectile dysfunction.