Mari Dezawa, Emiko Adachi-Usami. Role of Schwann cells in retinal ganglion cell axon regeneration. The site of the lesion of the visual pathway determines the shape and location of the scotoma. Nasal steps are nasal peripheral defects along the nasal horizontal meridian. Generalized depression though not strictly a scotoma is a lower sensitivity over the whole visual field which may be detected with visual field perimetry.
Retinal lesions correspond to the visual field defect.
For example, macular lesions cause centrocecal defects and retinal degenerative diseases like retinitis pigmentosa usually produce constricted fields and equatorial ring scotomas. Lesions at or beyond the optic chiasm result in scotomas with sharp naso-temporal edges. Slit lamp Optical examining tool for the front part of the eye. Referring to the cell body as opposed to the axon in a neuron. Much work is being done on understanding stem cells' transplant potential in treating many diseases including nerve tissue diseases.