The eyes have it: Part II

Recently, I mentioned some vision experiments that I dubbed "Life through a keyhole," and "The eyes have it: Part 1." Here is another example of a vision experiment performed on monkeys.

Citation: L Kiorpes, C Tang, and JA Movshon (2006) Sensitivity to visual motion in amblyopic macaque monkeys. Vis Neurosci 23(2): 247-56.

Summary of experiment: Nine young male rhesus macaques were used in the experiment. In addition, data from nine others used in an earlier study served as normal controls. For four of the experimental monkeys, a “lazy eye” was induced surgically at ~4 weeks of age. Judging from the detail in the methods section, surgery was performed under ketamine sedation rather than anesthesia and no analgesia was mentioned. The other five monkeys were raised wearing a single defocus lens beginning from ~4 weeks of age and ending before 8 months of age. Operant conditioning for visual tasks was used to measure the perception of motion ranging from very small to larger movements. Tests were done for motion at different speeds, visual distances and levels of contrast. General vision tests (like the ones humans get for glasses) were also performed.

Results: Under some conditions the lazy eye performed better than the “fellow” eye and under other conditions worse. In some cases, performance was roughly equal.

My notes:

• The first author has been publishing articles on monkey vision since at least 1984.


• Many of the papers cited in this article pertain to “lazy eye” and vision in humans. Why bother with a model?


• They mention providing visual and tactile enrichment for the monkeys who they are blinding. Infants and blind animals satisfy the requirements for special consideration under Section 3.81 of the AWA regarding psychological well-being.



• Infants were "obtained" from WaNPRC and hand-reared in the NYU visual neuroscience laboratory.


• Approved by UAWC and conformed to “the Guide.”


• Given the many test conditions in this experiment, and changes that take place as the animal ages and becomes more experienced (with the testing), the lack of independence between each eye in a pair belonging to a single monkey, the statistical analysis is suspect.

Affiliations: New York University Center for Neural Science

Funding Acknowledged: National Eye Institutes EY05864 and EY02017. Additional support was provided by an investigatorship from the Howard Hughes Medical Institute. Also acknowledged RR00166 to the Washington National Primate Research Center.