None listed
Conditions
Brief summary
Glaucoma is a blinding eye disease which can be treated by lowering eye pressure, or intraocular pressure (IOP). However some patients continue to get worse despite having an acceptably lowered IOP. IOP is determined by the production of aqueous fluid within the eye and the rate at which aqueous leaves the eye through the trabecular meshwork (TM). The eye-drop medication Ibopamine which temporarily increases aqueous production, has no effect on normal patients; however those with glaucoma will exhibit a rise in IOP when Ibopamine is applied. Possibly, patients whose glaucoma is progressively worsening despite having a low IOP measured in the clinic will demonstrate a larger increase in IOP with Ibopamine drops. We would like to recruit two groups of patients: one with glaucoma which is progressively deteriorating despite lowered IOP and one with stable glaucoma. We would then like to compare the change in their IOP when Ibopamine drops are applied to their eyes. Our aim is to validate this as a new test to predict which glaucoma patients will progress.
Interventions
Intraocular pressure (IOP) is dependent on the balance between the production of aqueous fluid within the eye and the rate at which aqueous leaves the eye through the trabecular meshwork (TM) in the angle of the eye’s anterior chamber. The medication Ibopamine (Trazyl: Pharmainvest SpA, Milano, Italy) which is a dopamine receptor agonist, will temporarily increase aqueous production and dilate the pupil. A healthy eye with healthy TM cells will overcome this increase, pump aqueous out of the eye at an increased rated and the patient will demonstrate no IOP rise when Ibopamine drops are applied topically to the eye, however there is evidence that those with glaucoma will exhibit a rise in IOP. It may be that patients whose glaucoma is progressively worsening, will demonstrate a larger increase in IOP when Ibopamine drops are applied topically to their eye compared with stable patients. To undertake an Ibopamine challenge, the patient has their IOP measured and recorded using goldmann applanation tonometry seated at the slit lamp; they then had two drops of Ibopamine 2% solution instilled into their eye; lastly their IOP is re-measured 45 minutes after receiving the Ibopamine eye drops and the IOP results pre and post the challenge are compared.
Sponsors
John Landers
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Diagnosis
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 90 Years
Healthy volunteers
No
Inclusion criteria
Primary open angle glaucoma (POAG) as defined by: characteristic and corresponding visual field and optic disc findings which are consistent with glaucoma and an intraocular pressure on treatment of at least 20% less than that prior to treatment. Progression is based on a worsening of visual field loss on three consecutive visual field tests performed over at least the preceding 24 months. Stability is based on a stable visual field on at least three consecutive visual field tests performed over the preceding 24 months.
Exclusion criteria
Exclusion criteria will include: those with forms of glaucoma other than POAG (e.g angle-closure glaucoma, secondary glaucoma etc.), those who have undergone previous intraocular surgery (except cataract surgery), those who were unable to perform a reliable visual field test and those who were unable to give informed consent.
Outcome results
None listed