Eyes wrong, eyes right: vision problems come and go.
Double vision--called diplopia--and involuntary jerky eye movements--called nystagmus--may improve with time mostly due to the ability of the nervous system to adjust itself to improve visual function.
A third common vision problem for people with MS is optic neuritis--an inflammation and demyelination of the optic nerve. The optic nerve is actually a bundle of fibers individually connected to parts of the retina. These fibers relay visual information to the brain.
Optic neuritis is often a first sign of MS. Between 50 and 70 percent of those diagnosed with this disorder only will go on to develop multiple sclerosis over a period of 2-15 years.
The initial symptoms of optic neuritis may include blurred vision, color blindness, pain behind the eye when it is moved, blind spots in the field of vision, or difficulty in seeing objects with poor contrast.
Experts say clinical improvement is likely in the first few weeks after the onset of the disorder. Optic neuritis rarely results in total blindness, and even that unusual condition is likely to improve, with the person regaining some sight.
But some MS vision problems may persist. With time and use, a number of the symptoms simply recede. Eye movements, double vision, or blind spots may slowly become less noticeable to the person or they may actually diminish. And the vision an individual has in one eye may compensate for deficiencies in the other.
Both ACTH and steroids have been used to treat all three of these eye disorders but, unfortunately, medications cannot prevent the conditions. At most they hasten improvement, which is likely to occur anyway. And they all carry the possibility of causing serious side effects. Thus the first question facing the physician and the patient is whether to treat the condition or to wait for it to get better on its own.
The second question concerns the choice of medication. ACTH, which prompts the body to produce natural steroids, is not used as much as it once was. Instead, neurologists tend to prefer prescribing laboratorymade steroids such as oral prednisone, and most recently, methylprednisolone, a steroid that is administered intravenously.
Recently, the question of which strategy works best was tested scientifically. Dr. Roy Beck of the Jaeb Center for Health Research in Tampa, Florida, headed a 457-patient, 15-center study in which IV (or intravenous) steroids, oral steroids and placebos (inert, look-alike compounds), were compared in the treatment of optic neuritis.
The IV steroid methylprednisolone was administered in 250-milligram doses every 6 hours for 3 days, followed by tapering-off doses of oral prednisone over 11 days. The group receiving oral prednisone alone was given 1 mg per kilogram of patient weight for 14 days, and the control group a placebo for 14 days.
"There was more rapid recovery of vision by using the IV steroids," Dr. Beck said, "although after about a month, there wasn't much difference in eyesight improvement" in all three groups.
Then, a second report on the study was published in the December 9, 1993 issue of The New England Journal of Medicine. This report claimed the IV steroids used to hasten recovery from optic neuritis, also delayed the development of MS in those people who were most likely to develop MS, based on their MRI results and other MS risk factors they might have.
Dr. Beck said that the analysis suggests the delaying effect of the IV steroids wears off after two years. Now, he is about to begin a new study to determine whether regular IV steroid therapy at six-month intervals might prolong this delay or reduce the number of exacerbations a person with MS would otherwise experience.
The National MS Society's Medical Advisory Board has pointed out that there is no established rationale to explain why IV steroids would produce this delaying effect. IV steroids have been used to treat exacerbations of MS for many years.
Lack of a reason why inevitably leads to questions. Has there been an error in interpreting the study?
Dr. Donald H. Silberberg, professor of neurology at the University of Pennsylvania, is among the skeptics. He was asked to comment on Dr. Beck's report in an editorial in The New England Journal of Medicine.
"There are many flaws in the paper that make its conclusions open to question," Dr. Silberberg said in a recent interview. "The study was not designed to ask whether IV steroids forestall MS. It was designed to ask whether they make optic neuritis better." In his opinion, "this controversy has confused neurologists, ophthalmologists and patients." He is particularly concerned about the side effects of IV steroid use, although Dr. Silberberg concedes that the incidence of serious side effects is low.
Dr. Beck points out that his data were analyzed by two independent biostatistic centers. But, he recommends some degree of caution. "Potential sources of bias were evaluated and seem unlikely to have produced the findings," he said. "But there is a possibility, though it seems small, that the findings could be due to chance."
What does Dr. Silberberg tell his own patients? If the vision loss is minor, he explains that improvement is likely without treatment and suggests that his patients simply wait it out. For those with serious visual loss, Dr. Silberberg recommends a moderately high dose of oral prednisone to hasten recovery.
Dr. Beck, on the other hand, would recommend three days of IV steroid therapy followed by oral prednisone, especially if his patient had any other neurologic symptoms suggestive of MS or "silent" symptoms, detected by MRI.
Other doctors have individual experiences and approaches.
"We need research to get at the underlying cause of optic neuritis. We also need additional properly done studies on IV steroids," Dr. Silberberg said. And on those points the community of MS specialists can easily agree.
But where does all this leave a person impaired by a bout of acute optic neuritis, who is living in a blurred world with pain accompanying every eye movement?
The Society's National Medical Advisory Board is very clear: Talk over your situation with a physician who is knowledgeable about MS, who knows you, and who is familiar with these studies. As in so many other areas of MS, an answer will apply to your individual situation, whether your concern is the treatment of acute optic neuritis or of exacerbations of MS.
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|Title Annotation:||Cover Story|
|Date:||Sep 22, 1994|
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