MANAGING SYMPTOMS( continued)
Diagnosis and Treatment
An ophthalmologist who has the patient’ s history can usually diagnose dry eye syndrome, though the exam confirms the diagnosis. The doctor’ s exam may show a reduced tear volume and rapid tear break-up time( the time for dry spots to occur on the cornea). A drop of fluorescein dye in the tear film allows the tear film to be better visualized. Some ophthalmologists will test tear production using specially prepared tear-strips( paper strips designed to absorb tears, which appear as a discolored area on the strip).
The severity of dry eye syndrome generally dictates the course of treatment. In most cases, the patient is advised to use artificial tear drops or eye ointment on a regular basis, perhaps four times a day. If the condition is treated with artificial tears chronically, many ophthalmologists will recommend non-preserved artificial tears. Although most of these products can be obtained without prescription, it is highly advisable to consult an eye doctor for advice. Excessive or prolonged use of artificial tears can disrupt the natural production of tears, leading to further aggravation of the condition instead of providing desired relief. A humidifier in the home, especially next to the bed at night, has been found to be particularly helpful for many patients. Because of the hardness of tap water in most areas, however, distilled water is usually required. Hard water will create an airborne mineral dust, which may make the humidifier less effective for its intended purpose
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Visual Disturbances of PSP
PSP does not lead to blindness. Any patient with PSP who begins to lose eyesight should see an eye specialist before attributing the loss of vision to PSP. The disorder does affect the control centers in the brain that generate eye movements. Thus, patients progressively lose the ability to move their eyes. During the early stages of the disorder, the eyes still move fully but slowly, particularly in upward and downward directions. Most patients do not experience any eye symptoms at this stage. As time goes on, the range of eye movements decline. Eventually total paralysis of eye movements ensues. In those with PSP, upward and downward gaze is more impaired than side-to-side gaze.
Inability to look down creates several problems. First, reading becomes difficult, and at times impossible, because patients can’ t look down and use their bifocals. Sometimes people with PSP cannot locate food on their plates. Family members may report that patients unknowingly leave food on their plates. The inability to look down impairs the ability to walk down stairs or to step off curbs, thereby increasing the risk of falls.
Inabilities to look up and sideways are less problematic. While reading, some patients find it hard to shift their gazes to the beginning of the next line after reaching the end of the previous line. Impaired horizontal gaze makes it difficult to scan the surrounding environment, giving patients the impression that their peripheral vision is constricted or that they have tunnel vision. This may lead to a sense of insecurity while walking and driving, activities that patients can still do early in the disease course. When patients express complaints about looking up or sideways, ophthalmologists may prescribe a new pair of glasses or even cataract removal, no matter how mild the cataract might be. Neither of these measures helps. Consulting with a neuro-ophthalmologist or neuro-optometrist can be very helpful, as they are more likely to be knowledgeable about how neurodegenerative diseases affect the eyes.
Another frequent cause of reading difficulty for those with PSP is convergence insufficiency. Besides not being able to look down, the patient cannot aim the eyes in the direction of the nose to focus at near objects and reading material. Because of the combination of failure to converge their eyes and to look down, many patients give up reading.