Astigmatism associated with experimentally induced myopia or hyperopia in chickens.

PURPOSE Astigmatism is a very common refractive error in humans, but its etiology is poorly understood. The primary purpose of this study was to determine whether alterations in visual experience would result in astigmatism in chicks. METHODS Longitudinal and cross-sectional data were obtained from chicks that were raised undergoing four different visual manipulations known to alter axial eye growth: form deprivation by translucent occluders, spherical defocus by -10- or +10-D lenses, and constant light. The visual manipulations began at 5 days of age and continued for a week. Age-matched groups raised without any treatment or with Velcro rings or plano lenses served as control groups. Refractions in all birds were measured with a Hartinger refractometer, and infrared photokeratometry was performed in a subset of birds at the end of the treatment period. RESULTS In control birds, natural astigmatism decreased in magnitude over the 7-day treatment period. In contrast, birds treated with visual manipulations developed significant amounts of astigmatism throughout the treatment period. At the end of the 7-day treatment period, whereas only 8.6% of the control chicks had refractive astigmatism >1 D, the percentage of treated birds that had astigmatism >1 D in each treatment group ranged from 66.7% to 100%. The astigmatism in the treated eyes was predominantly against-the-rule, corneal in nature, and correlated significantly with spherical ametropia of the principal meridians. CONCLUSIONS Visual manipulations known to induce axial ametropia also promote the genesis of astigmatism in chickens. The characteristics of astigmatism associated with spherical myopia or hyperopia in chicks is similar to those reported in humans in many respects, supporting the hypothesis that vision-dependent changes in eye growth may contribute to the astigmatism commonly found in humans.

[1]  E. Irving,et al.  Inducing ametropias in hatchling chicks by defocus—Aperture effects and cylindrical lenses , 1995, Vision Research.

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

[3]  J. Jonas,et al.  Optic disc shape, corneal astigmatism, and amblyopia. , 1997, Ophthalmology.

[4]  William J. Benjamin,et al.  Borish's clinical refraction , 1998 .

[5]  D. Mutti,et al.  Optical and structural development of the crystalline lens in childhood. , 1998, Investigative ophthalmology & visual science.

[6]  J. Wallman,et al.  Differences in time course and visual requirements of ocular responses to lenses and diffusers. , 2001, Investigative ophthalmology & visual science.

[7]  D. Mutti,et al.  Chapter 2 – Incidence and Distribution of Refractive Anomalies , 2006 .

[8]  P. Mitchell,et al.  Refractive errors in an older population: the Blue Mountains Eye Study. , 1999, Ophthalmology.

[9]  D. Mutti,et al.  Refractive error and ethnicity in children. , 2003, Archives of ophthalmology.

[10]  R. Held,et al.  Astigmatism and the development of myopia in children , 2000, Vision Research.

[11]  J. Rada,et al.  Regional proteoglycan synthesis in the sclera of experimentally myopic chicks. , 1994, Experimental eye research.

[12]  R Held,et al.  Astigmatism in children: changes in axis and amount from birth to six years. , 1984, Investigative ophthalmology & visual science.

[13]  G. Wilson.  The Effect of Lifting the Lids on Corneal Astigmatism , 1982, American journal of optometry and physiological optics.

[14]  Joseph M. Miller,et al.  Treatment of astigmatism-related amblyopia in 3- to 5-year-old children , 2004, Vision Research.

[15]  M. J. Hirsch.  Changes in astigmatism during the first eight years of school--an interim report from the Ojai longitudinal study. , 1963, American journal of optometry and archives of American Academy of Optometry.

[16]  K. Schmid,et al.  Natural and imposed astigmatism and their relation to emmetropization in the chick. , 1997, Experimental eye research.

[17]  Bernard Gilmartin,et al.  Myopia: precedents for research in the twenty‐first century , 2004, Clinical & experimental ophthalmology.

[18]  J. M. Garber.  High corneal astigmatism in Navajo school children and its effect on classroom performance. , 1981, Journal of the American Optometric Association.

[19]  P. Kronfeld,et al.  THE FREQUENCY OF ASTIGMATISM , 1930 .

[20]  H. Howland,et al.  Constant light produces severe corneal flattening and hyperopia in chickens , 1995, Vision Research.

[21]  G. V. van Alphen.  Choroidal stress and emmetropization. , 1986, Vision research.

[22]  H. Howland.  Infant eyes: optics and accommodation. , 1982, Current eye research.

[23]  James M. Newman.  Chapter 22 – Analysis, Interpretation, and Prescription for the Ametropias and Heterophorias , 2006 .

[24]  J. Woodhouse,et al.  Emmetropisation in human infancy: Rate of change is related to initial refractive error , 1995, Vision Research.

[25]  Janette Atkinson,et al.  Infant astigmatism: Its disappearance with age , 1980, Vision Research.

[26]  D. Lam,et al.  Astigmatism in Chinese preschool children: prevalence, change, and effect on refractive development , 2004, British Journal of Ophthalmology.

[27]  J. Simon,et al.  Astigmatism associated with adnexal masses in infancy. , 1987, Archives of ophthalmology.

[28]  K. C. Dean,et al.  CORNEAL ASTIGMATISM IN AMERIND CHILDREN* , 1972, American journal of optometry and archives of American Academy of Optometry.

[29]  K. Schmid,et al.  Retrospective Analysis of Refractive Errors in Children With Vision Impairment , 2005, Optometry and vision science : official publication of the American Academy of Optometry.

[30]  Jingjing Xu,et al.  Refractive error and visual impairment in urban children in southern china. , 2004, Investigative ophthalmology & visual science.

[31]  H. Rowland,et al.  Photokeratometric and photorefractive measurements of astigmatism in infants and young children , 1985, Vision Research.

[32]  Ying Qiao,et al.  Prevalence of astigmatism in infant monkeys , 2002, Vision Research.

[33]  L. Thibos,et al.  Power Vectors: An Application of Fourier Analysis to the Description and Statistical Analysis of Refractive Error , 1997, Optometry and vision science : official publication of the American Academy of Optometry.

[34]  Chien-Jen Chen,et al.  The Prevalence of Astigmatism in Taiwan Schoolchildren , 2004, Optometry and vision science : official publication of the American Academy of Optometry.

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

[36]  B. Heller.  Circular Statistics in Biology, Edward Batschelet. Academic Press, London & New York (1981), 371, Price $69.50 , 1983 .

[37]  S B Kaye,et al.  Association between total astigmatism and myopia , 1997, Journal of cataract and refractive surgery.

[38]  D. Plager,et al.  Resolution of astigmatism after surgical resection of capillary hemangiomas in infants. , 1997, Ophthalmology.

[39]  T. Wiesel,et al.  Myopia and eye enlargement after neonatal lid fusion in monkeys , 1977, Nature.

[40]  M. Banks.  Infant Refraction and Accommodation , 1980, International ophthalmology clinics.

[41]  J. Guggenheim,et al.  The association between spherical and cylindrical component powers. , 2004, Optometry and vision science : official publication of the American Academy of Optometry.

[42]  J. Rada,et al.  The sclera and myopia. , 2006, Experimental eye research.

[43]  M. Edwards.  The refractive status of Hong Kong Chinese infants , 1991, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[44]  Ing Mr.  The development of corneal astigmatism in contact lens wearers. , 1976 .

[45]  J. Waterbor,et al.  Distribution of astigmatism among Sioux Indians in South Dakota. , 1997, Journal of the American Optometric Association.

[46]  R. Stone,et al.  Photoperiod, early post-natal eye growth, and visual deprivation , 1995, Vision Research.

[47]  H. Howland,et al.  Differences in eye growth and the response to visual deprivation in different strains of chicken , 1995, Vision Research.

[48]  T. Grosvenor.  What causes astigmatism? , 1976, Journal of the American Optometric Association.

[49]  Scott A. Read,et al.  A review of astigmatism and its possible genesis , 2007, Clinical & experimental optometry.

[50]  I. Flitcroft,et al.  Retinal dysfunction and refractive errors: an electrophysiological study of children , 2005, British Journal of Ophthalmology.

[51]  S. Duke-Elder.  System of Ophthalmology , 1962 .

[52]  D. Mutti,et al.  Refractive Astigmatism and the Toricity of Ocular Components in Human Infants , 2004, Optometry and vision science : official publication of the American Academy of Optometry.

[53]  O. Braddick,et al.  Infant Emmetropization: Longitudinal Changes in Refraction Components from Nine to Twenty Months of Age , 1997, Optometry and vision science : official publication of the American Academy of Optometry.

[54]  D. Altman,et al.  STATISTICAL METHODS FOR ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENT , 1986, The Lancet.

[55]  J. M. Miller,et al.  Corneal and refractive astigmatism in a sample of 3- to 5-year-old children with a high prevalence of astigmatism. , 1999, Optometry and vision science : official publication of the American Academy of Optometry.

[56]  M. Ing.  The development of corneal astigmatism in contact lens wearers. , 1976, Annals of ophthalmology.

[57]  T Grosvenor,et al.  Predicting Refractive Astigmatism: A Suggested Simplification of Javal's Rule , 1988, American journal of optometry and physiological optics.

[58]  Frank Schaeffel,et al.  A simple mechanism for emmetropization without cues from accommodation or colour , 1994, Vision Research.

[59]  J. Lauber,et al.  Intraocular pressure and aqueous outflow facility in light-induced avian buphthalmos. , 1970, Experimental Eye Research.

[60]  R. A. Petersen,et al.  The relation of myopia and astigmatism in developing eyes. , 1982, Ophthalmology.

[61]  M. Orhan,et al.  Topographical Analysis of Corneal Astigmatism in Patients With Tilted-Disc Syndrome , 2002, Cornea.

[62]  T. Bender,et al.  High prevalence of myopia among young adult Yupik Eskimos. , 1985, Canadian journal of ophthalmology. Journal canadien d'ophtalmologie.

[63]  B. Becker,et al.  Research into the pathogenesis of keratoconus. A new syndrome: low ocular rigidity, contact lenses, and keratoconus. , 1970, Archives of ophthalmology.

[64]  H C Howland,et al.  Infant astigmatism measured by photorefraction. , 1978, Science.

[65]  Karla Zadnik,et al.  Axial growth and changes in lenticular and corneal power during emmetropization in infants. , 2005, Investigative ophthalmology & visual science.

[66]  K. Budak,et al.  Against-the-rule (ATR) astigmatism as a predicting factor for the outcome of amblyopia treatment. , 2002, American journal of ophthalmology.

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

[68]  Earl L. Smith,et al.  Astigmatism in Monkeys with Experimentally Induced Myopia or Hyperopia , 2005, Optometry and vision science : official publication of the American Academy of Optometry.

[69]  P. Mitchell,et al.  Population prevalence of tilted optic disks and the relationship of this sign to refractive error. , 2002, American journal of ophthalmology.

[70]  J. Siegwart,et al.  Regulation of the mechanical properties of tree shrew sclera by the visual environment , 1999, Vision Research.

[71]  C. Chan,et al.  The aging effect on corneal curvature and the validity of Javal's rule in Hong Kong Chinese. , 1999, Current eye research.

[72]  M J HIRSCH,et al.  Changes in astigmatism after the age of forty. , 1959, American journal of optometry and archives of American Academy of Optometry.

[73]  F. Solsona.  Astigmatism as a congenital, bilateral and symmetrical entity (observations based on the study of 51,000 patients). , 1975, The British journal of physiological optics.

[74]  P. Kiely,et al.  Astigmatism Occurring in Association with Pediatric Eye Disease , 1986, American journal of optometry and physiological optics.

[75]  Ying Qiao,et al.  Astigmatism in infant monkeys reared with cylindrical lenses , 2003, Vision Research.

[76]  R Held,et al.  Astigmatism in infants. , 1978, Science.

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

[78]  Bruce J W Evans,et al.  The Correlation Between Migraine Headache and Refractive Errors , 2006, Optometry and vision science : official publication of the American Academy of Optometry.

[79]  J M Bland,et al.  Statistical methods for assessing agreement between two methods of clinical measurement , 1986 .

[80]  F. Schaeffel,et al.  6-Hydroxy dopamine does not affect lens-induced refractive errors but suppresses deprivation myopia , 1994, Vision Research.

[81]  E. Smith,et al.  Continuous ambient lighting and eye growth in primates. , 2001, Investigative ophthalmology & visual science.

[82]  L B Ellwein,et al.  Ethnicity-specific prevalences of refractive errors vary in Asian children in neighbouring Malaysia and Singapore , 2006, British Journal of Ophthalmology.

[83]  O. Pärssinen.  Astigmatism and school myopia , 1991, Acta ophthalmologica.

[84]  G. V. Alphen.  Choroidal stress and emmetropization , 1986, Vision Research.

[85]  Johan Sjöstrand,et al.  Astigmatic axis and amblyopia in childhood. , 2003, Acta ophthalmologica Scandinavica.

[86]  R. A. Petersen,et al.  Cycloplegic refractions in infants and young children. , 1980, American journal of ophthalmology.

[87]  A. McKendrick,et al.  The Axis of Astigmatism in Right and Left Eye Pairs , 1997, Optometry and vision science : official publication of the American Academy of Optometry.

[88]  Gunilla Haegerstrom-Portnoy,et al.  Development of Refractive Errors into Old Age , 2002, Optometry and vision science : official publication of the American Academy of Optometry.

[89]  Earl L. Smith,et al.  Continuous Ambient Lighting and Lens Compensation in Infant Monkeys , 2003, Optometry and vision science : official publication of the American Academy of Optometry.