View clinical trials related to Cataract.
Filter by:This study will investigate whether people who donate granulocytes (a type of white blood cell) by leukapheresis are at increased risk of developing cataracts (changes in the lens of the eye that can impair vision). Apheresis is a method of collecting large numbers of white blood cells. The procedure is similar to donating whole blood, but the collected blood is circulated through a cell separator machine, the white cells are extracted, and the rest of the blood is returned to the donor. Before the procedure, donors are given a steroid called dexamethasone. This drug temporarily increases the number of granulocytes circulating in the blood, thus allowing twice as many of these cells to be collected. Recently, one blood collection center reported greater numbers of cataracts in a small number of granulocyte donors who had received repeated doses of steroids for granulocyte mobilization. The donors were unaware that they had the cataracts, which were small and did not affect their vision. Although people who take high doses of steroids over a long period time are known to have an increased risk of cataracts, steroids given infrequently (and in the doses used for granulocyte donation) have not been associated with cataracts. This study will examine the eyes of granulocyte donors and of platelet donors. Platelets-blood components necessary for clotting-are also collected by pheresis, but donors are not given steroids before the procedure. The examination findings will be compared to see if there is a difference in the risk of cataract formation in the two groups. People 18 years of age and older who have donated granulocytes or platelets at the NIH Department of Transfusion Medicine four times or more since 1984 may be eligible for this study. Participants will undergo the following procedures: - Detailed medical history, including allergies, corticosteroid use, diabetes mellitus, and asthma - Detailed eye history, including cataracts, glaucoma, other eye diseases and infections, eye trauma, and corrective lenses - Detailed history of sun exposure - Eye examination, including measurement of visual acuity (eye chart test) and eye pressure, examination of the lens and retina. - Photographs of the eye using a special camera
This study will use a newly developed instrument called dynamic light scattering device (DLS) to examine age-related changes in the human lens and to study the causes and development of cataracts. DLS uses a low intensity laser light (similar to that used in supermarket checkouts) to measures lens cloudiness. It detects changes in the human lens at the earliest stages, when anti-cataract treatment would be most effective in reversing, delaying or preventing cataract formation. Patients 18 years of age and older with cataracts and normal volunteers between the ages of 18 and 70 years may be eligible for this study. Participants will have a standard eye examination, including a vision check, pressure measurement, lens examination using DLS and examination of the retina. Photographs of the lens or retina, or both, may be taken. This study does not involve treatment. No anti-cataract medications will be given.
This study will assess the value of improved magnetic resonance imaging (MRI) techniques to study the lens of the human eye. Knowledge of how cataracts develop and progress has been hampered by the lack of human tissue available for study; MRI may provide an effective means for learning more about this eye disease. Normal volunteers between 18 and 70 years of age may be eligible for this study. Participants will undergo a medical history and complete eye examination, including vision assessment, eye pressure measurement, lens and retina examinations, and photography of the eye. MRI scans will be scheduled for a second visit. For this procedure, the volunteer's pupils are dilated and he or she then lies on a stretcher that is moved into a cylinder containing a magnetic field. A device similar to a welder's helmet is placed on the head. Attached to the device are an imaging probe and a small blinking light. The probe receives radio signals from the eye that a computer converts into images. During imaging, the participant gazes at the blinking light; this helps keep the eyes from blinking and wandering. Scan times vary from 2 to 10 minutes; the total time for the study is less than an hour.
This study will test the reliability of an instrument called the Quasi Elastic Laser Scattering Device (QLS) in detecting early changes in cataract formation. Surgery is currently the only treatment for cataracts. Many laboratories, however, are researching drugs to reverse, delay or prevent cataract formation. Anti-cataract drugs presumably would be most effective given early in the course of disease. When clinical trials of these drugs are begun, dependable and standardized methods for documenting and monitoring lens opacities will be needed to test their effectiveness. The QLS was designed to detect the earliest molecular changes in cataract development. This study will evaluate the usefulness and reliability of this instrument in measuring these changes. Normal volunteers and patients with cataracts in this study will have a standard eye examination, including a vision test and eye pressure measurement. The pupils will be dilated for QLS testing and for examination of the retina. Photographs of the retina may be taken. The QLS test uses a very dim laser light similar to that used to scan grocery items in the supermarket. The laser beam is projected into the lens of the eye, and the scattered light is collected and analyzed to determine normal and abnormal molecular interactions in the lens. Two measurements will be done for each eye. The test will be repeated in 6 months to determine reproducibility of the system.
Cataract, in which the lens of the eye is opacified, is the major cause of blindness. This study will examine protein material of the lens called crystallins to try to determine what causes nuclear cataracts, a type of cataract that forms in the central lens nucleus. Men and women age 45 years or older with a cataract may be eligible for this study. Candidates will be screened to determine what type of cataract they have and will undergo a complete eye examination, including a vision test, eye pressure test, and examination of the lens and retina. Patients selected for study will have a complete physical and eye examination, including photography of various parts of the eye, and ultrasound measurements of the eye. They will then have cataract surgery, either with or without intraocular lens implantation, and will have follow-up examinations 1 week, 3 weeks, 5 weeks and 8 weeks after surgery. Tissue from the lenses removed during surgery will be given to NEI scientists for research on the causes of age-related nuclear cataracts.
The objective of this study is to discover the genes responsible for the development of hereditary cataracts in families. A cataract is clouding of the lens of the eye that obstructs the passage of light and may impair vision. Information from this study may provide a better understanding of why hereditary cataracts form and perhaps lead to the development of a test that can predict who will likely be affected and to what degree. Patients or family members of patients with inherited cataracts who participate in this study will be asked questions about their family history, especially concerning eye disease or cataracts, and a family tree will be drawn. They will undergo a complete eye examination, including photographs to document the clarity or opacity of the lens. In addition, a small blood sample will be drawn for use in gene mapping studies of inherited cataract.
The efficacy of laser photocoagulation treatment for diabetic retinopathy has been demonstrated by several National Eye Institute (NEI) sponsored clinical trials. The Diabetic Retinopathy Study (DRS) demonstrated that scatter photocoagulation reduces the risk of blindness from diabetic retinopathy. The Early Treatment Diabetic Retinopathy Study (ETDRS) extended these findings by providing information on when to initiate scatter photocoagulation and by demonstrating that focal treatment was effective in treating macula edema. The Krypton Argon Regression Neovascularization Study (KARNS) showed that scatter photocoagulation with krypton red laser was just as safe and effective as the argon blue-green laser in the treatment of proliferative diabetic retinopathy. Unfortunately, there is little data on the long term effects of photocoagulation on visual function. The first objective of this study is to assess the long term effects of photocoagulation for diabetic retinopathy. A second objective is to provide additional information on the risk of progression of cataracts in persons with diabetes. All patients previously treated with laser photocoagulation (focal and/or scatter) are eligible to participate in this long term study. The first priority will be given to patients who participated in the ETDRS and KARNS because of the wealth of information available regarding the details of their treatment and course after treatment. Study evaluations will include a standard ophthalmic examination, fluorescein angiography, lens and fundus photography.
Clouding of the lens, or cataract formation, accounts for vision loss in about 45 percent of the U.S. population aged 75 to 85 years. Macular degeneration-destruction of the part of the retina responsible for central vision used in reading-is the leading cause of legal blindness in people over 60 years of age. This 10-year study on age-related macular degeneration and cataract will investigate: 1. The natural course and prognosis of these diseases; 2. The effects of vitamin and mineral supplements on their development and progression; and 3. Risk factors associated with their development. Patients with age-related macular degeneration or cataract will be evaluated for their eligibility in this study with a medical history, vision test and thorough eye examination, including photographs of the lens and back of the eye. Those accepted to the study will be randomly assigned to take one of the following 4 times a day: 1) a vitamin only; 2) a mineral only; 3) both a vitamin and a mineral; or 4) a placebo (a tablet with no active ingredient). A blood sample will be drawn at the beginning of the study and once a year until its end to measure vitamin and mineral blood levels and to study their effects on cholesterol. Participants will be asked to complete a voluntary questionnaire about their visual function and how it affects their daily lives. Some patients may be asked to participate in two interviews about 6 months apart, in which they will provide information on their food intake over a 24-hour period. This information will be used to explore possible dietary risk factors for macular degeneration and cataract. Participants may also be asked to provide a small blood sample for use in studying possible hereditary factors associated with age-related macular degeneration. This research may lead to a better understanding of why the condition develops, who is likely to be affected and to what degree, and how to improve treatment.
This study will test the effectiveness of an intraocular lens treated with heparin in reducing or preventing inflammation after cataract surgery in patients with uveitis. Patients with uveitis (inflammatory eye disease) often develop cataracts (clouding of the lens of the eye) that can impair eyesight. Cataracts can be removed surgically, and this is usually done when poor vision interferes with adequate daily functioning, or when the lens becomes too cloudy to evaluate the level of eye inflammation in uveitis-information needed to adjust medication dosages. After surgery, vision is corrected with special eyeglasses, contact lenses, or intraocular lenses (IOL). IOLs are small, plastic artificial lenses permanently placed inside the eye. Patients with uveitis who require cataract surgery and whose eye inflammation has been controlled by medicine for at least 3 months may be eligible for this study. Those enrolled in the study will be randomly assigned to one of two treatment groups: one group will have a standard IOL implanted during cataract surgery; the other will receive a heparin-treated IOL. Before surgery, patients will undergo standard preoperative tests, including chest X-ray, electrocardiogram, blood tests and urinalysis, as well as an eye examination that includes photography of the cornea, iris and retina. Additional tests and examinations to be done at the start of the study and at periodic follow-up visits for about 1 year may include: fluorescein angiography to evaluate the blood vessels of the retina; specular microscopy to examine the surface of the IOL; cell and flare measurements to evaluate inflammation, and ultrasound to examine the back of the eye.
To determine whether vitamin E supplementation reduces the risk of cataract and age-related macular degeneration (AMD) in women. To determine whether vitamin C supplementation reduces the risk of cataract and AMD in women. To determine whether beta-carotene supplementation reduces the risk of cataract and AMD in women. To determine whether alternate day, low-dose aspirin reduces the risk of cataract and AMD in women. To identify potential risk factors for cataract and AMD including cigarette smoking, alcohol intake, blood pressure, blood cholesterol, cardiovascular disease, height, body mass index, and diabetes.