Phosphodiesterase Inhibitors in Glaucoma Study (PhiGS)
Research type
Research Study
Full title
A pilot study to investigate the effect of phosphodiesterase inhibitors on chorioretinal blood flow using optical coherence tomography angiography
IRAS ID
253353
Contact name
Eduardo Normando
Contact email
Sponsor organisation
Imerial College London
Clinicaltrials.gov Identifier
Duration of Study in the UK
0 years, 8 months, 31 days
Research summary
Research 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.
Summary of Results
Purpose of the Study:
The study aimed to investigate whether phosphodiesterase inhibitors, a type of medication, could effectively treat glaucoma, which damages the eye's optic nerve and can lead to blindness.Participants:
The study planned to recruit 30 participants but ended up enrolling 15.Reason for Ending the Study Early:
The study was stopped early because the technology needed to take essential images was no longer available.Results:
The study was cut short, so the results are limited.
The initial findings suggest that phosphodiesterase inhibitors might help treat glaucoma, but more research is needed to confirm this.Impact on Participants:
There were no adverse effects on the participants due to the early termination of the study.Conclusion:
Although the study could not be completed as planned, it provided some useful insights into the potential of phosphodiesterase inhibitors for glaucoma treatment. Further studies are needed to understand their effectiveness fully.REC name
South West - Frenchay Research Ethics Committee
REC reference
19/SW/0078
Date of REC Opinion
16 May 2019
REC opinion
Further Information Favourable Opinion