Immediate and long-term effects on visual acuity of surgically induced strabismus in kittens (original) (raw)

Summary

In order to isolate some of the factors responsible for strabismic amblyopia as well as to ascertain the time course of its development, frequent measurements were made of the visual acuity of the two eyes of kittens following imposition of surgically induced strabismus. Following behavioural training on a jumping stand, strabismus was induced in all but one animal by simple section of either the lateral (esotropia) or medial (exotropia) rectus muscle of one eye. The one exception was a kitten on which esotropia was induced by another common but more radical surgical procedure that involved removal of the body of both the lateral rectus and superior oblique muscles of one eye. There was a surprising difference between the immediate consequences for vision of section of the lateral and medial rectus muscles that were reflected by equally large differences in the magnitude of the amblyopia that developed eventually in the two situations. Following section of the lateral rectus muscle, there was an immediate reduction in the visual acuity of the operated eye of as much as 2 octaves after which vision returned to normal levels over 4 to 8 days. The acuity of the two eyes remained comparable for a few days after which the vision of the operated eye began to decline once more, signalling the onset of amblyopia some 10 to 12 days following imposition of strabismus. In contrast to the severity of these effects, the effects observed following section of the medial rectus were both mild and transitory. Furthermore, whereas all kittens that were rendered esotropic early developed amblyopia, none of the kittens that were made exotropic at the same age did so. Together, these results suggest that factors associated with the immediate consequences of the surgical procedure employed to produce a misalignment of the visual axes may contribute to the severity of the effects of surgically induced strabismus.

Access this article

Log in via an institution

Subscribe and save

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

Download references

Author information

Authors and Affiliations

  1. Psychology Department, Dalhousie University, B3H 4J1, Halifax, N.S., Canada
    D. E. Mitchell, M. Ruck, M. G. Kaye & S. Kirby
  2. National Vision Research Institute of Australia, 386 Cardigan St., 3053, Carlton, Vic., Australia
    D. E. Mitchell

Authors

  1. D. E. Mitchell
    You can also search for this author inPubMed Google Scholar
  2. M. Ruck
    You can also search for this author inPubMed Google Scholar
  3. M. G. Kaye
    You can also search for this author inPubMed Google Scholar
  4. S. Kirby
    You can also search for this author inPubMed Google Scholar

Additional information

This research was supported by a grant (MA7732) to D.E.M. from the Medical Research Council of Canada. We wish to thank Keith Grasse for his assistance with the measurements of eye alignment under paralysis, and Cindy Trask and Heather Dzioba for their assistance with the behavioural testing

Rights and permissions

About this article

Cite this article

Mitchell, D.E., Ruck, M., Kaye, M.G. et al. Immediate and long-term effects on visual acuity of surgically induced strabismus in kittens.Exp Brain Res 55, 420–430 (1984). https://doi.org/10.1007/BF00235272

Download citation

Key words