{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,18]],"date-time":"2026-06-18T09:14:27Z","timestamp":1781774067089,"version":"3.54.5"},"reference-count":32,"publisher":"American Veterinary Medical Association (AVMA)","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["ajvr"],"published-print":{"date-parts":[[2010,6]]},"abstract":"<jats:title>Abstract<\/jats:title>\n<jats:p><jats:bold>Objective<\/jats:bold>\u2014To assess natural variations in degree of refraction, corneal curvature, corneal astigmatism, corneal radius, and intraocular distance of healthy equine eyes.<\/jats:p>\n<jats:p><jats:bold>Animals<\/jats:bold>\u2014159 horses with healthy eyes that were admitted to a veterinary teaching hospital for nonophthalmic surgeries.<\/jats:p>\n<jats:p><jats:bold>Procedures<\/jats:bold>\u2014Eyes of horses were examined with a retinoscope prior to anesthesia and with a keratograph and A- and B-scan ultrasonographic biometers during surgery. In addition, manual caliper measurements of horizontal and vertical corneal radii were obtained.<\/jats:p>\n<jats:p><jats:bold>Results<\/jats:bold>\u2014Mean \u00b1 SD degree of refraction in the horizontal meridian of eyes was \u22120.06 \u00b1 0.68 diopters (D). Vitreous body length and horse age correlated negatively with refraction values. The horizontal corneal radius (15.96 \u00b1 1.28 mm) was larger than the vertical corneal radius (15.02 \u00b1 1.09 mm). Accordingly, the vertical corneal curvature (21.56 \u00b1 1.68 D) was greater than the horizontal corneal curvature (22.89 \u00b1 1.65 D). Axial globe length (40.52 \u00b1 2.67 mm), anterior chamber depth (6.35 \u00b1 0.59 mm), lens thickness (12.30 \u00b1 0.83 mm), and vitreous body length (21.87 \u00b1 1.85 mm) were positively correlated with body weight, height, and age. Results of keratograph and caliper measurements correlated well for horizontal corneal diameter but poorly for vertical corneal diameter. Results of A- and B-scan ultrasonography differed by \u2264 1 mm in 64% of measured eyes.<\/jats:p>\n<jats:p><jats:bold>Conclusions and Clinical Relevance<\/jats:bold>\u2014Results of keratometry and ultrasonographic biometry varied widely. Additional research is needed to validate the keratograph used in our study for measurements in equine eyes.<\/jats:p>","DOI":"10.2460\/ajvr.71.6.677","type":"journal-article","created":{"date-parts":[[2010,6,1]],"date-time":"2010-06-01T07:06:16Z","timestamp":1275375976000},"page":"677-681","source":"Crossref","is-referenced-by-count":34,"title":["Evaluation of healthy equine eyes by use of retinoscopy, keratometry, and ultrasonographic biometry"],"prefix":"10.2460","volume":"71","author":[{"given":"Petra","family":"Grinninger","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Monika","family":"Skalicky","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Barbara","family":"Nell","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1272","reference":[{"key":"ref1","series-title":"The retinoscopy book","author":"Corboy","year":"2003"},{"key":"ref2","series-title":"Equine Vet J Suppl","first-page":"91","article-title":"Follow-up report of a case of surgical aphakia with an analysis of equine visual function","volume":"10","author":"Farrall","year":"1990"},{"key":"ref3","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"157","DOI":"10.1046\/j.1463-5224.2000.00139.x","article-title":"Cataract phacofragmentation in horses","volume":"3","author":"Millichamp","year":"2000"},{"key":"ref4","series-title":"Vet Ophthalmol","first-page":"255","article-title":"Refractive error in Rocky Mountain Horses with cornea globosa and with normal cornea","volume":"2","author":"Ramsey","year":"1999"},{"key":"ref5","series-title":"Vet Ophthalmol","first-page":"255","article-title":"The normal refractive state of the equine","volume":"2","author":"Stuhr","year":"1999"},{"key":"ref6","series-title":"Osterr Wochenschr Tierheilkd","first-page":"125","article-title":"\u00dcber die Entstehung der Myopie bei Pferden","volume":"13","year":"1912"},{"key":"ref7","series-title":"Z Vgl Augenheilkd","first-page":"21","article-title":"Beitr\u00e4ge zur Dioptrik der Krystalllinse","volume":"4","author":"Matthiessen","year":"1886"},{"key":"ref8","series-title":"Z Vgl Augenheilkd","first-page":"17","article-title":"\u00dcber den physikal-optischen Bau des Pferdeauges","volume":"8","author":"Berlin","year":"1882"},{"key":"ref9","series-title":"Am J Vet Res","first-page":"735","article-title":"Physical optics of the equine eye","volume":"38","author":"Knill","year":"1977"},{"key":"ref10","series-title":"Dtsch Z Tiermed Vgl Pathol","first-page":"53","article-title":"\u00dcber Form-, Lage- und Gr\u00f6\u03b2enverh\u00e4ltnisse der Orbita, des Bulbus und der Krystalllinse unserer Haustiere","volume":"9","author":"Koschel","year":"1883"},{"key":"ref11","series-title":"Equine Vet J Suppl","first-page":"9","article-title":"An ophthalmic survey of the neonatal horse","volume":"2","author":"Latimer","year":"1983"},{"key":"ref12","series-title":"Large animal ophthalmology","first-page":"101","author":"Lavach","year":"1990"},{"key":"ref13","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"183","DOI":"10.1046\/j.1463-5216.2001.00147.x","article-title":"Description of ciliary body anatomy and identification of sites for transscleral cyclophotocoagulation in the equine eye","volume":"4","author":"Miller","year":"2001"},{"key":"ref14","series-title":"Am J Vet Res","doi-asserted-by":"publisher","first-page":"661","DOI":"10.2460\/ajvr.2003.64.661","article-title":"Assessment of corneal thickness, intraocular pressure, optical corneal diameter, and axial globe dimensions in Miniature Horses","volume":"64","author":"Plummer","year":"2003"},{"key":"ref15","series-title":"Vis Res","doi-asserted-by":"publisher","first-page":"1353","DOI":"10.1016\/0042-6989(75)90189-3","article-title":"An evaluation of the \u201cramp\u201d retina of the horse eye","volume":"15","author":"Sivak","year":"1975"},{"key":"ref16","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"47","DOI":"10.1046\/j.1463-5224.1999.00050.x","article-title":"Congenital abnormalities of Rocky Mountain Horses","volume":"2","author":"Ramsey","year":"1999"},{"key":"ref17","series-title":"J Am Vet Med Assoc","first-page":"1706","article-title":"Ocular diagnostic ultrasonography","volume":"153","author":"Rubin","year":"1968"},{"key":"ref18","series-title":"Vet Ophthalmol","first-page":"437","article-title":"Assessment of axial globe dimensions in juvenile horses","volume":"8","author":"Townsend","year":"2005"},{"key":"ref19","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"357","DOI":"10.1111\/j.1463-5224.2006.00493.x","article-title":"Ocular biometry, determination of corneal curvature and prediction of intraocular lens power in the equine eye","volume":"9","author":"McMullen","year":"2006"},{"key":"ref20","series-title":"Vet Radiol","doi-asserted-by":"publisher","first-page":"24","DOI":"10.1111\/j.1740-8261.1986.tb00616.x","article-title":"Evaluation of the extirpated equine eye using B-mode ultrasonography","volume":"27","author":"Rogers","year":"1986"},{"key":"ref21","series-title":"Kleintierpraxis","first-page":"127","article-title":"Biometrie am Hundeauge","volume":"33","author":"Neumann","year":"1988"},{"key":"ref22","series-title":"Invest Ophthalmol Vis Sci","first-page":"2459","article-title":"Myopia and refractive error in dogs","volume":"33","author":"Murphy","year":"1992"},{"key":"ref23","series-title":"Am J Vet Res","first-page":"1317","article-title":"Corneal thickness, intraocular pressure, and optical corneal diameter in Rocky Mountain Horses with cornea globosa or clinically normal corneas","volume":"60","author":"Ramsey","year":"1999"},{"key":"ref24","article-title":"Anatomy and histology of the eye and 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vitreous","volume":"40","author":"Jansson","year":"1962"},{"key":"ref29","first-page":"1","article-title":"Ophthalmologie v\u00e9t\u00e9rinaire et compar\u00e9e","author":"Nicolas","year":"1914"},{"key":"ref30","series-title":"Othalmic Physiol Opt","doi-asserted-by":"publisher","first-page":"215","DOI":"10.1111\/j.1475-1313.1988.tb01040.x","article-title":"Schematic eyes for domestic animals","volume":"8","author":"Coile","year":"1988"},{"key":"ref31","series-title":"Am J Vet Res","first-page":"898","article-title":"Ultrasonographic and biometric evaluation of the eye and orbit of dogs","volume":"50","author":"Cottrill","year":"1989"},{"key":"ref32","series-title":"Vet Radiol Ultrasound","doi-asserted-by":"publisher","first-page":"502","DOI":"10.1111\/j.1740-8261.1999.tb00382.x","article-title":"Agreement between A-mode and B-mode ultrasonography in the measurement of ocular distances","volume":"40","author":"Hamidzada","year":"1999"}],"container-title":["American Journal of Veterinary 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