Peripheral nasal field defects in glaucoma.

One hundred fifty-one eyes of 101 consecutive patients with chronic open-angle and low tension glaucoma showed typical visual field changes. Sixty of the eyes had a nasal step, either alone or in combination with other defects. In 17 of these eyes, it was possible to demonstrate an isolated scotoma in the nasal periphery. It was concluded that the peripheral nasal step is a nerve fiber bundle defect that in its earliest phase produces a scotoma. In this sense, it behaves similar to the more central defects, rather than simply as a depression of isopters nasally.