What is nasal step scotoma?
In practice the nasal step is an early and characteristic glaucomatous field defect like the isolated scotomas in the Bjerrum area, and it is easily detected and can be used as a sensitive marker in the follow up of glaucomatous damage.
What is scotoma involving central area?
A central scotoma is a blind spot that occurs in the center of one’s vision. It can appear in several different ways. It may look like a black or gray spot for some and for others it may be a blurred smudge or a distorted view in one’s straight ahead vision.
What causes Bjerrum scotoma?
Bjer·rum sco·to·ma A scotoma shaped like a comet’s tail; occurs in glaucoma, attached at the temporal end to the blind spot or separated from it by a narrow gap; the defect widens as it extends above and nasally curves around the fixation spot, and then extends downward to end exactly at the nasal horizontal meridian.
What is superior nasal step defect?
Because the superior field is involved somewhat more frequently than the inferior portion is in the early stages of glaucoma, the nasal step more often results from a greater defect above the horizontal midline, which is referred to as a superior nasal step.
What causes nasal step defect?
Nasal step defects are caused by optic nerve disorders that affect the long, arching axons that originate temporal to the macula, entering the disc superiorly or inferiorly. A nasal step may begin as a small depression above or below (and respecting) the horizontal meridian in the nasal visual field (see Figure 3–8A).
What does scotoma mean?
A scotoma is an aura or blind spot that obstructs part of your vision. Scintillating scotomas are blind spots that flicker and waver between light and dark.
How is central scotoma treated?
Typically, scintillating scotomas don’t require treatment. In most cases, the blind spot will resolve on its own within about an hour. Lying down to rest, closing your eyes, drinking water, and taking an over-the-counter pain reliever, such as ibuprofen or acetaminophen, may help to relieve mild symptoms of scotomas.
How do you test for central scotoma?
A visual field test is a method of measuring an individual’s entire scope of vision, that is their central and peripheral (side) vision. Visual field testing maps the visual fields of each eye individually and can detect blind spots (scotomas) as well as more subtle areas of dim vision.
What is the confrontation test?
Confrontation visual field testing involves having the patient looking directly at your eye or nose and testing each quadrant in the patient’s visual field by having them count the number of fingers that you are showing. This is a test of one eye at a time.
Why is it called a nasal step?
The isopter position is different above and below the nasal horizontal meridian; this produces the “nasal step” described by Bjerrum and Rønne,” wrote Anderson and Patella in Automated Static Perimetry (p.
What is a scotoma in medical terms?
What is a ring scotoma?
Ring scotomas are annular visual field defects centred on fixation. The ring may be mid-peripheral, in which case the annulus passes between 30 and 60 degrees; pericentral, in which case the ring incorporates the physiological blind spot; or central.