Identification and Treatment of Feeder Vessels in Macular Degeneration
This study will try to identify and treat feeder vessels in age-related macular degeneration. The macula is the part of the retina in the back of the eye that determines central or best vision. In macular degeneration, leaking blood vessels under the macula lead to loss of central vision. These vessels branch out tree-like from one or more feeder vessels. Instead of treating all the abnormal branching vessels, this study will try to find and close only the feeder vessels, thereby depriving the abnormal vessels of nutrition. The vessels will be closed with laser beam treatment.
People 50 years of age and older with macular degeneration and visual acuity worse than 20/50 in the study eye and the same or better vision in the other eye may be eligible for this study. Candidates will undergo fluorescein angiography to try to locate feeder vessels. For this procedure, a yellow dye is injected into an arm vein. The dye travels to the blood vessels in the eyes, and pictures of the retina are taken using a camera that flashes a blue light into the eye. The pictures show if any dye has leaked from the vessels into the retina, indicating possible blood vessel abnormality.
Before laser treatment, participants will have a complete eye examination, including measurement of visual acuity, evaluation of the front part of the eye with a slit lamp microscope, examination of the retina with an ophthalmoscope, and measurement of eye pressure using a tonometer.
During the laser treatment phase of the study, participants will have indocyanine green angiography-a procedure similar to fluorescein angiography, but using a green dye-to photograph the retina and identify feeder vessels. If feeder vessels are located, laser beam treatment will begin. For this procedure, the eye is anesthetized with numbing drops. A special contact lens is then placed on the eye for the laser treatment. The number of treatments depends on how well the individual patient responds, but usually between two and eight treatments are required.
The indocyanine green angiogram will be repeated after the laser beam treatment to determine if the feeder vessels have been successfully closed. If the vessels remain partially open, a repeat application will be done, followed by another indocyanine green angiogram to check the results.
Patients will be checked in the clinic after 1 week to see if additional treatment is needed. If so, re-treatment will be done in a week. If no re-treatment is required, follow-up visits will be scheduled 2, 3, and 6 weeks after treatment, 3 and 6 months after treatment, and every 6 months after that for 2 years to evaluate treatment results. The evaluations will include fluorescein angiograms and other examinations that were done before starting treatment. If abnormal vessels are still present or growing, repeat treatments will be applied following the same procedure.
Procedure: Laser Treatment
|Study Design:||Primary Purpose: Treatment|
|Official Title:||Feasibility Study of the Identification and Treatment of Feeder-Vessels of Choroidal Neovascularization in Age-Related Macular Degeneration|
|Study Start Date:||June 2001|
|Estimated Study Completion Date:||August 2006|
Age-related macular degeneration (AMD) represents the most common cause of blindness in patients over the age of 60. Most vision loss in this disease results from sequelae of choroidal neovascular membrane (CNVM) formation. CNVM is usually composed of well-formed neovascularization and occult (less well-formed) neovascularization. While clinical trials have shown that some patients, mostly those with well-formed CNVM, may benefit from laser photocoagulation or photodynamic therapy, at present there is no treatment for patients who have combined CNVM lesions (both well-formed and occult) whose area of occult neovascularization is greater than 50% or who have other presentation of CNVM such as pigment-epithelial detachment or neovascular fibrosis.
Retinal histopathology of patients with choroidal neovascularization has revealed that areas of CNVM are usually fed by a few smaller choroidal feeder vessels originating from the choroid or choriocapillaris. Therefore, it has been hypothesized that closure of these feeder vessels would infarct the large CNVM complex. Until recently, identification of these feeder vessels has been difficult but new high speed indocyanine imaging of the choroid (Phi-motion) indocyanine green angiography (ICG) has allowed for more precise detection of these vessels. We will test this hypothesis by utilizing Phi-motion ICG to identify choroidal feeder vessels in patients with CNVM not amenable to approved treatments. If feeder vessels are identified, then pulse-diode laser photocoagulation will be used to attempt closure of these vessels. The study is designed to provide information on the feasibility of standardizing this procedure and estimating its potential efficacy. The primary outcome will be a greater than 50% reduction in the area of leakage from the neovascular component as determined by fluorescein angiogram. Secondary outcomes will include a complete resolution of leakage measured by fluorescein angiography, the number of repetitive laser treatments undergone, the number of patients eligible by fluorescein angiogram but without identifiable feeder vessels, and the number of patients with vision loss, from baseline, of 15 letters or more, 30 letters or more, or are reduced to less than 5 letters read. All adverse events regardless of severity or relatedness to the therapy will be collected and summarized. Assessment of all outcomes will be made at 6 weeks, 3, 6, 12, 18, and 24 months post laser treatment, and 24 months after enrollment. This study will give investigators some insight into this technology and the feasibility of this treatment in patients with various forms of neovascular AMD. In addition, the results of the study will provide the foundation for larger studies of this therapy.
|United States, Maryland|
|National Eye Institute (NEI)|
|Bethesda, Maryland, United States, 20892|