The effect of positive lens defocus on ocular growth and emmetropization in the tree shrew.

Optical defocus influences postnatal ocular development in animal models. Induced negative lens defocus results in accelerated ocular elongation and myopia. Positive lens-induced defocus findings across animal models have been inconsistent. Specifically, in the tree shrew, positive lens-induced defocus has produced equivocal results. This study evaluated the response of the tree shrew to induced positive lens defocus. One treatment group wore positive lenses binocularly, which were increased in power sequentially from +2 to +4, +6, +8, and +9.5 D over 8 weeks. Other groups wore +4, +6, and +9.5 D lenses, respectively, for 8 weeks. Animals wearing zero-powered (plano) lenses served as controls. Refractive error and ocular dimensions were measured at the start of treatment and every week thereafter. Sequentially increasing positive lens power caused a relative hyperopia of +5.6 D (p < 0.01) compared to the plano lens group (+10.9 +/- 1.8 D vs +5.3 +/- 0.5 D). Constant +4 D lens wear produced +6.9 D relative hyperopia, while +6 and +9.5 D lens wear did not induce hyperopia. Lens-induced defocus changes in refractive state were significantly correlated with vitreous chamber depth changes. The threshold for consistent responses to positive lens defocus in tree shrew was between +4 and +6 D. The results will enable targeted investigation of the efficacy of positive lens defocus in inhibiting myopic ocular growth.

[1]  M. Millodot,et al.  Retinoscopy and Eye Size , 1970, Science.

[2]  P. Kiely,et al.  Effects of retinal image degradation on ocular growth in cats. , 1984, Investigative ophthalmology & visual science.

[3]  Torsten N. Wiesel,et al.  An animal model of myopia. , 1985, The New England journal of medicine.

[4]  W A Ray,et al.  Statistical analysis of multi-eye data in ophthalmic research. , 1985, Investigative ophthalmology & visual science.

[5]  J. Wallman,et al.  Local retinal regions control local eye growth and myopia. , 1987, Science.

[6]  J. Wallman,et al.  Developmental aspects of experimental myopia in chicks: Susceptibility, recovery and relation to emmetropization , 1987, Vision Research.

[7]  Adrian Glasser,et al.  Accommodation, refractive error and eye growth in chickens , 1988, Vision Research.

[8]  Earl L. Smith,et al.  Effects of chronic optical defocus on the kitten's refractive status , 1989, Vision Research.

[9]  Neville A. McBrien,et al.  The development of experimental myopia and ocular component dimensions in monocularly lid-sutured tree shrews (Tupaia belangeri) , 1992, Vision Research.

[10]  Neville A. McBrien,et al.  Normal development of refractive state and ocular component dimensions in the tree shrew (Tupaia belangeri) , 1992, Vision Research.

[11]  E. Irving,et al.  Refractive plasticity of the developing chick eye , 1992, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[12]  Josh Wallman,et al.  Chapter 6 Retinal control of eye growth and refraction , 1993 .

[13]  N. Mcbrien,et al.  Atropine reduces experimental myopia and eye enlargement via a nonaccommodative mechanism. , 1993, Investigative ophthalmology & visual science.

[14]  J. Siegwart,et al.  Goggles for controlling the visual environment of small animals. , 1994, Laboratory animal science.

[15]  Josh Wallman,et al.  Choroidal and scleral mechanisms of compensation for spectacle lenses in chicks , 1995, Vision Research.

[16]  J. Fischbarg.  A rapidly emerging field: water channel proteins in the eye. , 1995, Investigative ophthalmology & visual science.

[17]  K. Zadnik,et al.  How applicable are animal myopia models to human juvenile onset myopia? , 1995, Vision Research.

[18]  Earl L. Smith,et al.  Spectacle lenses alter eye growth and the refractive status of young monkeys , 1995, Nature Medicine.

[19]  Lynn Marran,et al.  Moving the retina: Choroidal modulation of refractive state , 1995, Vision Research.

[20]  N. Mcbrien,et al.  The M1 muscarinic antagonist pirenzepine reduces myopia and eye enlargement in the tree shrew. , 1996, Investigative ophthalmology & visual science.

[21]  C. Wildsoet,et al.  Active emmetropization--evidence for its existence and ramifications for clinical practice. , 1997, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[22]  E. Smith,et al.  Spectacle lenses and emmetropization: the role of optical defocus in regulating ocular development. , 1998, Optometry and vision science : official publication of the American Academy of Optometry.

[23]  K. Schmid,et al.  Sharp vision: a prerequisite for compensation to myopic defocus in the chick? , 1998, Current eye research.

[24]  S. Judge,et al.  The effects of spectacle wear in infancy on eye growth and refractive error in the marmoset (Callithrix jacchus) , 1999, Vision Research.

[25]  Earl L. Smith,et al.  The role of optical defocus in regulating refractive development in infant monkeys , 1999, Vision Research.

[26]  M. Tigges,et al.  Effects of muscarinic cholinergic receptor antagonists on postnatal eye growth of rhesus monkeys. , 1999, Optometry and vision science : official publication of the American Academy of Optometry.

[27]  N. Mcbrien,et al.  Optical correction of induced axial myopia in the tree shrew: implications for emmetropization. , 1999, Optometry and vision science : official publication of the American Academy of Optometry.

[28]  N. Mcbrien,et al.  Scleral remodeling during the development of and recovery from axial myopia in the tree shrew. , 2000, Investigative ophthalmology & visual science.

[29]  J. Wallman,et al.  Temporal constraints on lens compensation in chicks , 2002, Vision Research.

[30]  J. Wallman,et al.  Potency of myopic defocus in spectacle lens compensation. , 2003, Investigative ophthalmology & visual science.

[31]  J. Siegwart,et al.  Binocular Lens Treatment in Tree Shrews , 2003 .

[32]  H. Wagner,et al.  The eye of the blue acara (Aequidens pulcher, Cichlidae) grows to compensate for defocus due to chromatic aberration , 1996, Journal of Comparative Physiology A.

[33]  Jonathan Winawer,et al.  Ocular compensation for alternating myopic and hyperopic defocus , 2005, Vision Research.

[34]  Jonathan Winawer,et al.  In a matter of minutes, the eye can know which way to grow. , 2005, Investigative ophthalmology & visual science.

[35]  Jonathan Winawer,et al.  Homeostasis of Eye Growth and the Question of Myopia , 2012, Neuron.