Timothy C. Hain, MD • Page last modified: March 8, 2021
Occasionally individuals with acquired blindness develop a pendular nystagmus, the so-called "nystagmus of the blind" (e.g. Devogelaere et al, 2006; Lorenz and Gampe, 2001).
In some cases, the blindness is from prosaic causes such as diabetic retinopathy, in others it is associated with retinal disease such as retinitis pigmentosa, advanced macular degeneration, achromatopsia or albinism. In albino's, the nystagmus is thought to be due to co-existing abnormalities in the wiring of the optic chiasm. Furthermore, according to the pediatric literature, Visual disorders, present during early life, can also produce a pendular nystagmus. It usually resolves spontaneously in 1-4 years.
We are not sure why nystagmus of the blind is occasional, or why it often resolves in children.
Persons that are nearly blind will often perform very poorly on tracking tests that require central vision, but rarely have nystagmus. It is important in these people also to note that calibration may be difficult, but here there is no issue.
This pursuit test is from a woman with advanced macular degeneration and no central vision. In spite of having very poor pursuit, her OKN was normal.
This particular patient also had increased phase on her rotatory chair, and upbeating nystagmus with vibration. Perhaps these are related to loss of calibration of the VOR.