 |
|
Simple eye scan opens window to multiple sclerosis
October 16, 2007Potential to track the disease at a fraction of the cost of current test
A five-minute eye exam might prove to be an inexpensive and effective way to gauge and track the debilitating neurological disease multiple sclerosis, potentially complementing costly magnetic resonance imaging to detect brain shrinkage - a characteristic of the disease's progression.
A Johns Hopkins-based study of a group of 40 multiple sclerosis (MS) patients used a process called optical coherence tomography (OCT) to scan the layers of nerve fibers of the retina in the back of the eye, which become the optic nerve. The process, which uses a desktop machine similar to a slit-lamp, is simple and painless. The retinal nerve fiber layer is the one part of the brain where nerve cells are not covered with the fat and protein sheathing called myelin, making this assessment specific for nerve damage as opposed to brain MRI changes, which reflect an array of different types of tissue processes in the brain.
Results of the scans were calibrated using accepted norms for retinal fiber thickness and then compared to an MRI of each of the patient's brains - also calibrated using accepted norms. Experimenters found a correlation coefficient of 0.46, after accounting for age differences. Correlation coefficients represent how closely two variables are related -- in this case MRI of the brain and OCT scans. Correlation coefficients range from -1 (a perfect opposing correlation) through 0 (no correlation) to +1 (a perfect positive correlation). In a subset of patients with relapsing remitting MS, the most common form of the disease, the correlation coefficient jumped to 0.69, suggesting an even stronger association between the retinal measurement and brain atrophy.
"This is an encouraging result," says Johns Hopkins neurologist Peter Calabresi, M.D., lead author of the study, which appears in the October 2007 issue of Neurology. "MRI is an imperfect tool that measures the result of many types of tissue loss rather than specifically nerve damage itself. With OCT we can see exactly how healthy these nerves are, potentially in advance of other symptoms."
In addition, says Calabresi, OCT scans take roughly one-tenth as long and cost one-tenth as much as the MRI, which means they are faster and cheaper to use in studies that track the effectiveness of new treatments for MS.
Approximately 400,000 people in the United States have MS, marked by an abnormal immune system that attacks and kills a person's own brain cells. As these neurons die, the volume of the brain decreases. MRI of the brain, which can measure total volume, has long been the primary tool used to monitor MS. But MRI, aside from being expensive and uncomfortable, is often misleading since brain inflammation - also a symptom of the disease - can skew brain volume readings. Also, the brain begins shrinking relatively late in the progression of the disease, so MRI isn't as good at detecting the disease in its early stages when treatments are most effective. OCT scans look directly at the thickness, and therefore health, of the optic nerve, which is affected early on in the disease, often before the patient suffers permanent brain damage.
Calabresi added that many of the disabilities suffered by MS patients - numbness, tingling, visual impairment, fatigue, weakness and bladder function disturbance - are the result of nerve cell degeneration, so a test that specifically measures nerve cell health is potentially the clearest picture of the status of the disease.
He cautions that optic nerve damage can point to a number of diseases and is not a unique diagnostic tool for MS. However, he says, it certainly sends up a flag suggesting that MS might be present. And since optic nerve damage is one of the first recognizable symptoms of MS, doctors have a chance to identify the disease potentially before the patient suffers the physical limitations generally associated with its advanced stages.
"Treatments for MS cannot reverse the damage but they can arrest it, so the earlier we get someone on medication the quicker we can stop the disease from causing more harm," says Calabresi. This tool may be useful as an outcome measure in MS clinical trials to assess the efficacy of neuroprotective drugs.
In the study, researchers recruited 40 patients from the Johns Hopkins MS clinic. Twenty had relapsing remitting MS, 15 had secondary progressive MS, and five had primary progressive MS. Researchers also recruited 15 healthy control patients free from ophthalmological or neurological disease as a comparison group.
Calabresi says his next step will be to look at changes in the fiber layer thickness in 100 patients over a period of three years.
Johns Hopkins Medical Institutions
Results of the scans were calibrated using accepted norms for retinal fiber thickness and then compared to an MRI of each of the patient's brains - also calibrated using accepted norms. Experimenters found a correlation coefficient of 0.46, after accounting for age differences. Correlation coefficients represent how closely two variables are related -- in this case MRI of the brain and OCT scans. Correlation coefficients range from -1 (a perfect opposing correlation) through 0 (no correlation) to +1 (a perfect positive correlation). In a subset of patients with relapsing remitting MS, the most common form of the disease, the correlation coefficient jumped to 0.69, suggesting an even stronger association between the retinal measurement and brain atrophy.
"This is an encouraging result," says Johns Hopkins neurologist Peter Calabresi, M.D., lead author of the study, which appears in the October 2007 issue of Neurology. "MRI is an imperfect tool that measures the result of many types of tissue loss rather than specifically nerve damage itself. With OCT we can see exactly how healthy these nerves are, potentially in advance of other symptoms."
In addition, says Calabresi, OCT scans take roughly one-tenth as long and cost one-tenth as much as the MRI, which means they are faster and cheaper to use in studies that track the effectiveness of new treatments for MS.
Approximately 400,000 people in the United States have MS, marked by an abnormal immune system that attacks and kills a person's own brain cells. As these neurons die, the volume of the brain decreases. MRI of the brain, which can measure total volume, has long been the primary tool used to monitor MS. But MRI, aside from being expensive and uncomfortable, is often misleading since brain inflammation - also a symptom of the disease - can skew brain volume readings. Also, the brain begins shrinking relatively late in the progression of the disease, so MRI isn't as good at detecting the disease in its early stages when treatments are most effective. OCT scans look directly at the thickness, and therefore health, of the optic nerve, which is affected early on in the disease, often before the patient suffers permanent brain damage.
Calabresi added that many of the disabilities suffered by MS patients - numbness, tingling, visual impairment, fatigue, weakness and bladder function disturbance - are the result of nerve cell degeneration, so a test that specifically measures nerve cell health is potentially the clearest picture of the status of the disease.
He cautions that optic nerve damage can point to a number of diseases and is not a unique diagnostic tool for MS. However, he says, it certainly sends up a flag suggesting that MS might be present. And since optic nerve damage is one of the first recognizable symptoms of MS, doctors have a chance to identify the disease potentially before the patient suffers the physical limitations generally associated with its advanced stages.
"Treatments for MS cannot reverse the damage but they can arrest it, so the earlier we get someone on medication the quicker we can stop the disease from causing more harm," says Calabresi. This tool may be useful as an outcome measure in MS clinical trials to assess the efficacy of neuroprotective drugs.
In the study, researchers recruited 40 patients from the Johns Hopkins MS clinic. Twenty had relapsing remitting MS, 15 had secondary progressive MS, and five had primary progressive MS. Researchers also recruited 15 healthy control patients free from ophthalmological or neurological disease as a comparison group.
Calabresi says his next step will be to look at changes in the fiber layer thickness in 100 patients over a period of three years.
Johns Hopkins Medical Institutions
Optic Nerve Current Events and Optic Nerve News RSSEye conditions linked with obstructive sleep apnea
If a good night's sleep helps the brain and body perform better, it's a good guess that sleep problems can cause more than just fatigue. Numerous studies have shown a connection between sleep disorders and medical conditions such as cardiovascular disease, cerebrovascular disease, and metabolic disorders, including the risk of obesity and diabetes mellitus. In the November issue of Mayo Clinic Proceedings, Mayo Clinic researchers outline several interesting associations between sleep disorders and eye disease.
A second career for a growth factor receptor: keeping nerve axons on target
Neurons constituting the optic nerve wire up to the brain in a highly dynamic way. Cell bodies in the developing retina sprout processes, called axons, which extend toward visual centers in the brain, lured by attractive cues and making U-turns when they take the wrong path.
New marker for raised intracranial pressure
Magnetic resonance imaging (MRI) measurements of the thickness of the optic nerve sheath are a good marker for raised intracranial pressure (ICP).
Best treatment for MS may depend on disease subtype
Animal studies by University of Michigan scientists suggest that people who experience the same clinical signs of multiple sclerosis (MS) may have different forms of the disease that require different kinds of treatment.
Glaucoma procedure now available at Mayo Clinic aims to prevent further eye damage
For the first time in Florida, patients with glaucoma have a new treatment option known as the Trabectome.
Severe retinal hemorrhaging is linked to severe motor vehicle crashes
The severity of retinal hemorrhaging for young children in motor vehicle crashes is closely correlated to the severity of the crash, according to a new study by researchers at the Medical College of Wisconsin in Milwaukee.
Glaucoma report points to increased costs
A new Centre for Eye Research Australia/ Access Economics report shows the cost of glaucoma will more than double in the next two decades.
Young patients with knee disorder get active after new Stanford surgical procedure
At 14 years old, Adam Vasser of Los Altos, Calif., was an active kid who loved baseball. Then a mysterious virus attacked his heart, making a heart transplant necessary to save his life.
'Fluorescent' cells give early warning for eye disease
Scientists at the University of Michigan have shown that their new metabolic imaging instrument can accurately detect eye disease at a very early stage.
Role identified for glaucoma gene and related signaling pathway
Researchers have found that a gene and a related signaling pathway play a role in the development of glaucoma, which is a common cause of visual impairment and blindness worldwide.
More Optic Nerve Current Events and Optic Nerve News Articles
 | Optic Nerve: Perceptual Art of the 1960s by Joe Houston The abstract art movement Op art came to international attention in the mid-1960s, an era of global social and technological change. The movement, which placed emphasis on viewer perception by exploring optical effects in painting, sculpture and light installation, quickly gained in popularity but met with considerable criticism. This important book, published to accompany the first... |
 | Optic Nerve Disorders (Ophthalmology Monograph Series) Ophthalmologists need to be familiar with a wide variety of optic nerve diseases that may occur in isolation or form part of a generalized neurological or systemic disorder. Optic Nerve Disorders provides a succinct-yet-comprehensive review of the optic nerve disorders commonly encountered in clinical practice, briefly reviews the anatomy and physiology of the optic nerve, and outlines those... |
 | Primary Optic Nerve Sheath Meningioma (Medical Radiology / Radiation Oncology) Optic nerve sheath meningioma (ONSM) is a rare tumour. Cases are usually separated into primary ONSM, which arises either intraorbitally or, less commonly, intracanalicularly, and secondary ONSM, which arises intracranially and subsequently invades the optic canal and orbit. This is the first book to cover all important aspects of the diagnosis and treatment of primary ONSM. After a general... |
 | Optic Nerve Disorders: Diagnosis and Management by Jane W. Chan The optic nerve and the brain comprise the main anatomic components of neuro-ophthalmology. Although there are numerous handbooks and major texts describing all the common disorders of neuro-ophthalmology, Optic Nerve Disorders is the only practical reference book focusing only on common optic nerve disorders. The author discusses diagnosis, pathophysiology, management, and prognosis of complex... |
| Optic Nerve 2, November 1995 by Adrian Tomine | |
| Optic Nerve 9, October 2004 - Shortcomings Part 1 by Adrian Tomine | |
| Optic Nerve #11 by Adrian Tomine Acclaimed small press comic which started as a duplicated flyer, and evolved into one of the most successful alternative black and white comic... | |
 | 32 Stories: The Complete Optic Nerve Mini-Comics In 1991, Adrian Tomine self-published the first issue of Optic Nerve. Consisting of three xeroxed sheets of paper, and with a print run of twenty-five, it was a less-than-auspicious, largely unnoticed debut. In the following three years, though, Optic Nerve developed at a startlingly rapid pace: the artwork and writing evolved with each story, production quality improved, page counts increased,... |
| Optic Nerve Disease Research Perspectives by Benjamin D. Lewis, Charlie James Davies Optic nerve diseases is the second commonest cause of blindness world-wide. The diagnosis and clinical management of these conditions depends critically on accurate, reliable and sensitive methods of assessing damage to the optic nerve fibres. The techniques currently available include functional tests (such as visual perimetry, electro-diagnostic tests or evaluation of the pupillary light reflex... | |
 | Optic Nerve: 30 Postcards This remarkably illustrated collection of postcards features the best of Tomine's distinctive, critically acclaimed Optic Nerve comic book series, as well as selections from his work for magazines such as The New Yorker, album covers, and more. Share these 30 different postcards or keep them all to... |
| © 2008 BrightSurf.com |