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Completed

NCT Number: NCT00957190

The DIOXXACT Trial(Diurnal IOP and OBF Xalatan vs Xalatan And Cosopt Trial)

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.

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Key information

Conditions

Eye Disease Eye Diseases Glaucoma Glaucoma, Open-Angle Ocular Hypertension

Age range

30 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Maisonneuve-Rosemont Hospital

Montreal, Quebec, H1T 2M4, Canada

About this study

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

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Dorzolamide 20 mg and Timolol 5 mg

Drug

Twice daily in the affected eye(s)

Other names: Cosopt

Primary outcomes

  1. Clinical evidence for lower diurnal variational Intraocular Pressure

    Time frame: Six weeks

Secondary outcomes

  1. The Intraocular Pressure, Retinal and choroidal blood flow will be stabilized on Cosopt therapy

    Time frame: Six weeks

Sponsors and collaborators

Lead sponsor

Maisonneuve-Rosemont Hospital

Other

Collaborators

  • Merck Sharp & Dohme LLC

Registry information

Official study 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

Acronym: DIOXXACT

Important dates

Study start
2009
Primary completion
2011
Study completion
2012
First posted
Aug 12, 2009
Registry last updated
Mar 27, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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