A Pilot Study to Investigate the Effect of Phosphodiesterase Inhibitors on Chorioretinal Blood Flow Using Optical Coherence Tomography Angiography.
试验速览
- 阶段
- 3 期
- 状态
- 暂停
- 入组人数
- 30
- 试验地点
- 1
- 主要终点
- Changes in central macular thickness as assessed by retina imaging
研究概览
简要总结
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.
详细描述
Hypotheses
This study is examining the hypothesis that Phosphodiesterase inhibitors increase chorio-retinal blood flow; in other words, we hypothesise that drugs like Viagra that have a known effect of generally increasing circulation may also increase the blood flow in the back of the eye -retina, with possible beneficial effect.
Study design
This is a small pilot study which is not expected to produce a definitive answer to our question -however, if successful this study will enable us to progress to a larger study that will have much more data to base our conclusions on.
Our present study will, therefore, examine both healthy and glaucomatous eyes with regards to the level of blood flow in the retina - something that can be measured using optical coherence tomography (OCT), a safe and non-invasive procedure which has been in use as part of the standard of care for some time.
研究设计
- 研究类型
- Interventional
- 分配方式
- Non Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- None
入排标准
- 年龄范围
- 40 Years 至 80 Years（Adult, Older Adult）
- 性别
- Male
- 接受健康志愿者
- 否
入选标准
- •Able to give informed consent to participate in the study
- •Aged between 40 and 80 years of age
- •Clear optical media
- •Spherical equivalent +-10D
- •IOP 21mmHg
排除标准
- •have used sildenafil for 48 hours (4 hour half-life) and tadalafil for 5 days (48 hour half-life).
- •have a known adverse reaction to any phosphodiesterase inhibitors
- •have an inherited photoreceptor disease (manufacturer contra-indication)
- •have any other known ocular disease (except glaucoma in this cohort)
- •have had non-arteritic anterior ischaemic optic neuropathy (manufacturer precaution due to lack of long term visualfield studies)
- •are on current ritonavir, erythromycin, cimetidine treatment (Manufacturer advises if concurrent use of ritonavir is unavoidable, the max. dose should not exceed 25 mg within 48 hours)
- •have serious cardiac or liver disease (manufacturer contra-indication)
- •have had a stroke or myocardial infarction (manufacturer contra-indication) within 6 months
- •have anatomical deformation of the penis or conditions predisposing to priapism (sickle cell anaemia, leukaemia, multiple myeloma)
- •have hypotension (manufacturer contra-indication) BP<100/60
- •have secondary or narrow/closed angle glaucoma
研究组 & 干预措施
eyes with glaucoma
patients with glaucoma will have imaging of retina post administration of Sildenafil or Tadalafil.
干预措施: Sildenafil 100mg (Drug)
Healthy (unaffected) eyes
patients with healthy eyes who are already taking Sildenafil or Tadalafil have their imaging of retina post administration of Sildenafil or Tadalafil.
干预措施: Sildenafil 100mg (Drug)
结局指标
主要结局
Changes in central macular thickness as assessed by retina imaging
时间窗: 30 minutes, 60 minutes, 120 minutes
OCT and angiographic findings before and after drug administration including
Changes in retinal vascular density as assessed by retina imaging
时间窗: 30 minutes, 60 minutes, 120 minutes
OCT and angiographic findings before and after drug administration including
Changes in choroidal vascular density as assessed by retina imaging
时间窗: 30 minutes, 60 minutes, 120 minutes
OCT and angiographic findings before and after drug administration including
Changes in central choroidal thickness as assessed by retina imaging
时间窗: 30 minutes, 60 minutes, 120 minutes
OCT and angiographic findings before and after drug administration including
Changes in choroidal flow as assessed by retina imaging
时间窗: 30 minutes, 60 minutes, 120 minutes
OCT and angiographic findings before and after drug administration including
Changes in outer retina flow as assessed by retina imaging
时间窗: 30 minutes, 60 minutes, 120 minutes
OCT and angiographic findings before and after drug administration including
次要结局
未报告次要终点