Humane Research Australia (HRA) and Action for Primates are calling for an end to the funding of baby monkey vision experiments by the Australian charity, the Brien Holden Vision Institute Ltd.
Myopia (near-sightedness) research partly funded by the Australian charity involving the rearing of infant monkeys in low intensity lighting has recently been published (1). The work was carried out at the University of Houston in the USA, in collaboration with researchers from the Brien Holden Institute. Seven two-week-old infant rhesus macaques (Macaca mulatta) were used. The infants had been removed from their mothers and continued to be subjected to maternal deprivation throughout the experiment. Forcibly separating infants from their mothers, and then depriving them of each other, is extremely cruel and an extremely distressing experience for mother and infant.
At around 24 days of age, the infants were transferred to an area in which there was reduced lighting. The infants remained under these conditions (except for brief removals to do measurements on ocular development) until they were about 10 months or 310 days of age. The overhead lighting in the room during ‘daylight’ hours was only 55 lux, but the amount of light as measured at the fronts of the cages was only seven to 36 lux; light levels were just above twilight light levels typically encountered outdoors. This is completely aberrant for the normal daytime habitat in which rhesus monkeys live. These infant monkeys, therefore, had to endure not only the fear and distress of social and maternal deprivation in a completely abnormal environment for their well-being, but also the near-dark conditions. Control data were acquired from age-matched monkeys who were reared similarly, but under typical laboratory lighting.
For the various tests to measure ocular development, the infants were injected with a sedative and their heads were covered with a light-blocking cloth while they were transferred to the measuring facility to collect data, including inserting contact lenses. These tests were carried out every two weeks for the first seven months, then every month until the end of the experiment. No information was provided as to the fate of the seven infant monkeys.
The authors found that dim-light rearing of these monkeys did not result in myopia, rather it subtly altered ocular structure and optical refraction (bending of light). No tests were done to determine if any of this had any effect on vision for these individuals; all the measurements were physical, not functional, in nature.
The data derived from this inhumane treatment of infant monkeys are essentially valueless. The authors even acknowledged this: “A limitation of our study was that the illumination level, as well as the duration of exposure, was not representative of real-world scenarios. In addition, whereas transitioning between relatively lower and higher ambient lighting frequently takes place in daily life; our subjects were deprived of such opportunities.”
Rachel Smith, Chief Executive Officer, of HRA , stated: “Australian charities should be held accountable for the research they are funding. I am sure donors would be shocked to learn of the cruelty their donations are contributing to, with no translatable value to human patients. HRA encourages donors to consult the Humane Charities List to ensure they avoid funding animal research such as this.”
Dr Nedim Buyukmihci, Emeritus Professor of Veterinary Medicine at the University of California, Ophthalmologist and spokesperson for Action for Primates, stated: “Research has already been done in people to show that an increase in ambient light protects children from developing myopia [see reference 2]. Why, therefore, were these infant macaques deliberately caused to suffer? This is work simply designed to continue using non-human primates as ‘models’ for human refractive error development, as alluded to by the authors. It is of no medical value to human patients, but of enormous psychological cost to the monkeys and should be discontinued. The authors, however, advocate the carrying out of further similar research using non-human primates, something that should not be allowed, not just because of its inhumanity, but also because of its lack of scientific credibility.”
Vision research on infant macaques, involving some of the US and Australian authors of this study, has been carried out over many years, also publicly funded by grants from the National Institutes of Health, funds from the Vision Cooperative Research Centre in Australia (Brien Holden Vision Institute) and the University of Houston Foundation. One such study involved rearing infant monkeys with red filters over one or both eyes (3). The filters were held by goggle helmets that provided monocular and binocular fields of view. Except for brief periods needed for routine cleaning and maintenance, the monkeys wore the helmets continuously from about 25 to 146 days of age.
References:
1. She, Zhihui; Hung, Li-Fang; Arumugam, Baskar; Beach, Krista M. and Smith, Earl L. 2020-08-07. “Effects of low intensity ambient lighting on refractive development in infant rhesus monkeys (Macaca mulatta)” Vision Research 176:48-59.
Published under Creative Commons license
2. Hua, Wen-Juan; Jin, Ju-Xiang; Wu, Xiao-Yan; Yang, Ji-Wen; Jiang, Xuan; Gao, Guo-Peng and Tao, Fang-Biao. 2015-05-01. “Elevated light levels in schools have a protective effect on myopia” Ophthalmic & Physiological Optics 35(3):252-262.
3. Smith, Earl L.; Hung, Li-Fang; Arumugam, Baskar; Holden, Brien A.; Neitz, Maureen and Neitz, Jay. 2015-10-01. “Effects of Long-Wavelength Lighting on Refractive Development in Infant Rhesus Monkeys” Investigative Ophthalmology & Visual Science 56(11):6490-6500.