This grant addresses aspects of the general question: how do neural and hormonal pathways work together to establish regulation of refraction and growth of both eyes during early postnatal development? These pathways are important in coordinating development of eye movements, eye size, refraction and emmetropization. As such, their investigation is of singular importance in understanding the genesis of refractive error, strabismus, and amblyopia in humans. This study is particularly focused on the regulation of growth of the anterior segment of the eye. Using the chick model we will 1a) determine if the signal responsible for protection from constant light effects (flattened cornea, shallow anterior chamber & hyperopia) is a periodic increase in melatonin concentration, and investigate the causal chain linking illumination and melatonin concentrations; 1b) determine whether the elongation of the vitreous chamber in constant light results from emmetropization growth, induced by the hyperopia that is caused by the flattening of the cornea; 1c) investigate the role of autonomic effects on the growth of the anterior segment; 2) investigate the light-dependent growth influences of one eye on another by various manipulations including optic nerve section, selective retinal cell destruction by drugs, and the generation of unilaterally micro-ophthalmic chicks. 3) investigate the mode of coupling of the light dark cycle to the circadian melatonin rhythm with the aid of mathematical models. Behavioral, surgical, biochemical, histological, and mathematical methods will be employed to answer these questions.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY002994-22
Application #
6518300
Study Section
Special Emphasis Panel (ZRG1-VISB (03))
Program Officer
Oberdorfer, Michael
Project Start
1979-07-01
Project End
2004-05-31
Budget Start
2002-06-01
Budget End
2003-05-31
Support Year
22
Fiscal Year
2002
Total Cost
$256,102
Indirect Cost
Name
Cornell University
Department
Other Basic Sciences
Type
Schools of Arts and Sciences
DUNS #
City
Ithaca
State
NY
Country
United States
Zip Code
14850
Wahl, Christina; Li, Tong; Howland, Howard C (2016) Intraocular pressure fluctuations of growing chick eyes are suppressed in constant light conditions. Exp Eye Res 148:52-54
Wahl, Christina; Li, Tong; Howland, Howard (2015) Plasticity in the growth of the chick eye: emmetropization achieved by alternate morphologies. Vision Res 110:15-22
Wahl, Christina; Li, Tong; Takagi, Yuko et al. (2011) The effects of light regimes and hormones on corneal growth in vivo and in organ culture. J Anat 219:766-75
Wahl, Christina; Li, Tong; Choden, Tsering et al. (2009) Morphometrics of corneal growth in chicks raised in constant light. J Anat 214:355-61
Li, Tong; Howland, Howard C (2006) Role of the pineal gland in ocular development of the chick in normal and constant light conditions. Invest Ophthalmol Vis Sci 47:5132-6
Ronneburger, Ariel; Basarab, Jennifer; Howland, Howard C (2006) Growth of the cornea from infancy to adolescence. Ophthalmic Physiol Opt 26:80-7
Howland, Howard C (2005) Allometry and scaling of wave aberration of eyes. Vision Res 45:1091-3
Kelly, Jennifer E; Mihashi, Toshifumi; Howland, Howard C (2004) Compensation of corneal horizontal/vertical astigmatism, lateral coma, and spherical aberration by internal optics of the eye. J Vis 4:262-71
Howland, Howard C; Merola, Stacey; Basarab, Jennifer R (2004) The allometry and scaling of the size of vertebrate eyes. Vision Res 44:2043-65
Schaeffel, Frank; Burkhardt, Eva; Howland, Howard C et al. (2004) Measurement of refractive state and deprivation myopia in two strains of mice. Optom Vis Sci 81:99-110

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