The DIOXXACT Trial(Diurnal IOP and OBF Xalatan vs Xalatan And Cosopt Trial)
Information source: Maisonneuve-Rosemont Hospital
ClinicalTrials.gov processed this data on August 23, 2015 Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Eye Disease
Intervention: Dorzolamide 20 mg and Timolol 5 mg (Drug)
Phase: Phase 4
Status: Enrolling by invitation
Sponsored by: Maisonneuve-Rosemont Hospital Official(s) and/or principal investigator(s): Mark R Lesk, MSc,MD, Principal Investigator, Affiliation: Maisonneuve-Rosemont Hospital
Summary
Diurnal and intervisit fluctuations in IOP are strongly associated with progression of open
angle glaucoma and therefore need to be minimized. Control of diurnal fluctuations of IOP
with different ocular hypotensive medications has been studied in some detail. But how do
IOP changes contribute to progressive glaucomatous optic nerve damage? It is reasonable to
assume that there are two principal effects of IOP changes. First, IOP fluctuations result
in changes in the stresses and strains on the ONH which in turn result in morphological
changes to the ONH. These morphological changes could in turn result in stretching and
damage to axons of the ONH. Secondly, IOP fluctuations results in changes to the forces
acting on the ONH vasculature, leading to changes in ONH vascular perfusion. These changes
to perfusion could in turn result in relative ischemia of the ONH and consequent ONH damage.
The investigators propose to monitor diurnal fluctuations in IOP and choroidal blood flow
(Pulsatile Ocular Blood Flow,POBF), and intervisit ONH topographical and blood flow
changes—ie to monitor the direct ONH consequences of IOP . Open angle glaucoma patients are
commonly prescribed topical latanoprost as first line therapy. The EXACCT study, for which I
was the principal investigator and which is now submitted for publication, demonstrated that
COSOPT was an efficacious choice as second line therapy for patients not controlled on
latanoprost monotherapy. The investigators will therefore recruit 20 OAG patients on
latanoprost monotherapy, perform diurnal curves of IOP, as well as a. m. ONH morphology and
ONH blood flow. Cosopt will then be added and at the next visit the same measurements will
be repeated.
The investigators expect that when Cosopt is added the investigators will demonstrate
improved IOP, morphology and blood flow compared to the latanoprost baseline. Furthermore
the investigators expect the the diurnal fluctuation of IOP and choroidal blood flow will be
stabilized on Cosopt therapy. The implications are that adding Cosopt to latanoprost can
stabilize not only the IOP but also the damaging consequences of IOP to the optic nerve
head.
Clinical Details
Official title: Change in Optic Nerve Head Blood Flow,Optic Nerve Topography and Diurnal Fluctuation of Intraocular Pressure and Pulsatile Ocular Blood Flow in Glaucoma:Cosopt and Xalatan vs Xalatan Alone
Study design: Allocation: Non-Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label
Primary outcome: Clinical evidence for lower diurnal variational Intraocular Pressure
Secondary outcome: The Intraocular Pressure, Retinal and choroidal blood flow will be stabilized on Cosopt therapy
Detailed description:
Twenty patients with open angle glaucoma or ocular hypertension currently on latanoprost
immunotherapy will be recruited.
A complete routine ophthalmic examination including biomicroscopy, gonioscopy and fundus
ophthalmoscopy will be performed. The eye with better visual acuity is selected for fundus
flowmetry.
All patients will undergo a complete diurnal workup including IOP, as well as 10am Confocal
scanning laser ophthalmoscopy (Heidelberg Retina Tomography-3) of ONH topography. Optic
nerve head, nasal and temporal peripapillary retinal blood flow are measured with scanning
laser Doppler flowmetry (SLDF; Heidelberg Retinal Flowmeter/Tomograph, SLDF analysis
software v3. 3, Heidelberg Engineering, Germany Goldmann IOP will be measured at 8am, 10am
2pm and 4pm. Pulse amplitude, similar to Pulsatility Ocular Blood Flow (POBF) will be
measured using the Pascal Dynamic Contour Tonometer (DCT) at 8am, 10am, 2pm, and 4 pm.
All procedures will conform to the Declaration of Helsinki and the study will be approved by
the Ethics Committee and each patient will sign an informed consent form.
Following visit one, Cosopt will be added to the patients therapy (bid). Following 6 weeks
of therapy patients will return for visit two. Cosopt will be applied by the investigator at
8am on visit 2.
We expect that this blood flow will be improved with COSOPT therapy and that the diurnal
fluctuation of this parameter will be improved as well. It is evidently of great interest to
examine diurnal changes in ocular blood flow with and without COSOPT and the measurement of
POBF can be performed without great cost and is well tolerated by the patient.
Changes in IOP, ONH Topography, and ONH blood flow will be analysed using appropriate
statistical approaches
Eligibility
Minimum age: 30 Years.
Maximum age: 80 Years.
Gender(s): Both.
Criteria:
Inclusion Criteria:
- Subjets with open angle glaucoma or ocular hypertension currently on latanoprost
immunotherapy.
- Subjets must have clear media, corrected visual acuity of 6/12 or better,and be able
to sit for imaging.
Exclusion Criteria:
- Subjets with contraindications or known allergies to any of the components of Cosopt.
- Subjets who had undergoing laser or any ocular surgery.
Locations and Contacts
Maisonneuve-Rosemont Hospital, Montreal, Quebec H1T 2M4, Canada
Additional Information
Starting date: June 2009
Last updated: August 11, 2009
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