The Effects of Low Intensity Ambient Lighting on Refractive Development in Rhesus Monkeys (Macacca mulatta)

PURPOSE: Elevated ambient lighting levels protected animals from certain forms of experimental myopia, suggesting that alterations in ambient lighting levels influence refractive development. The purpose of the studies reported in this dissertation was to evaluate the extent to which low ambient lighting influences refractive development in primates and to determine whether and how low ambient lighting levels cause myopias. METHODS: Infant rhesus monkeys (Macaca mulatta) were reared under reduced or “dim” ambient lighting (~50 lux) with either unrestricted vision or one of the monocular lens treatments that induces experimental anisometropias. The development of their refractive errors, corneal powers, and ocular axial dimensions was measured longitudinally and compared to those in monkeys reared under typical laboratory lighting (“normal” light) with the same visual conditions. Their choroidal thickness changes were also longitudinally measured to reflect the activity of refractive regulation. RESULTS: The results showed that (1) dim light did not produce myopia in monkeys reared with unrestricted vision, but increased the variability in refractive error and reduced the likelihood of successful emmetropization; (2) dim light did not increase nor reduce the magnitude of form-deprivation myopia (FDM), but interfered with the refractive development after the discontinuation of form-deprivation and reduced the probability of recovery form FDM; (3) dim light reduced the probability of lens-induced compensating changes, increased the variability in refractive development, and reduced the degree of compensating anisometropias. All refractive observations were associated with alterations in vitreous chamber depth. The failures in developing the anticipated vision-induced anisometropias were associated with an absence of vision-induced relative choroidal thickness changes. CONCLUSIONS: Dim light is not necessarily myopiagenic; however, extended exposure to dim light could cause myopia through reductions in the efficacy of visual mechanisms that normally regulate refractive development.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Physiological Optics and Vision Science

Grantor

University of Houston

Year dc:date.issued

2021

Author dc:creator

• She, Zhihui

Advisor dc:contributor.advisor

• Smith, Earl L., III

Committee members dc:contributor.committeemember

• Frishman, Laura J.
• Patel, Nimesh B.
• Ostrin, Lisa A.
• Wildsoet, Christine F.

• Lighitng level
• dim light
• myopia
• emmetropization
• form-deprivaiton myopia
• lens-induced myopia
• lens-induced hyperopia

Statement dc:rights

• The author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. UH Libraries has secured permission to reproduce any and all previously published materials contained in the work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/10657/8128

OAI identifier oai:identifier

oai:uh-ir.tdl.org:10657/8128