These researches are directed at finding a practical method for identifying infants and young children who are at risk of developing amblyopia due either to uncorrected refractive errors or subtle motor problems. They are also aimed at finding the physiological basis of an effective preventative therapy for refractive amblyopia and severe ametropia by investigating emmetropizing mechanisms in humans and animals. To accomplish these goals it is proposed to conduct both human and animal studies on refractive development. In the human work, our 15 year longitudinal study of refractive development will be extended by refracting infants and children of our volunteer population with visible light photorefractive and infrared autorefractive methods. In particular a new binocular infrared autorefractive method, developed partially in our laboratory, will be employed. Data on parental and familial refractive status will also be gathered. This refractive data will be used to construct a practical method for the prediction and, hopefully, the prevention of amblyopia on the basis of refractive and motor behavior measured in infancy. The laboratory's animal work will continue to concentrate on the study of the growth of eyes of chicks, focusing now on the image-directed regulation of growth of the anterior chamber. We will investigate the nature of the compensation for astigmatic defocus, and we will employ conditions of constant light to isolate one of the two important feedback mechanisms of image controlled growth. We will also examine the optical methods by which the chick eye maintains optical quality during accommodation in the face of a large change of aberration structure of the cornea. From a knowledge of the emmetropization mechanisms of chicks, we hope to gain insights into both the normal and the pathological development of human refractive states.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY002994-17
Application #
2158588
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1979-07-01
Project End
1998-06-30
Budget Start
1995-07-01
Budget End
1996-06-30
Support Year
17
Fiscal Year
1995
Total Cost
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
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
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

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