The Refraction of the Eye Author: G Hartridge Publisher: J & A Churchill Date: 1919 flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, the refraction of the eye, book

Optometrists are trained to examine eyes and prescribe visual aids such as spectacles. The optometer pictured in the media section of this document dates from the 1800s. The optometer was used with various lenses to determine the refraction of the eye. Refraction means the extent to which light is bent by an individual's eye. The result can determine how short-sighted or long-sighted they are, and the strength of spectacles required. In the second half of the 1800s, ophthalmologists also devised instruments to measure the separate components of vision. Dr Jules Badal developed the pictured instrument in 1876. It was based on an optometer invented by William Porterfield in 1759. The brass stands look as though they were made for an optometer to be table mounted, with heavy brass stands and designed to hold a cylindrical object securely as would be required by an optometer. Stands appear to have been very well made and very early probably early to mid 19th Century by a well known scientific instrument maker given there are no inscriptions or marks to indicate the time period made or maker it is difficult to assume significance to these items at this point in time as well as the items are incomplete.The brass stands believed to be for mounting an early Optometer an (ophthalmic instrument) Noneflagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, stands for scientific instrument

How widely the prisoptometer was used is unclear but the Standard Optical Company later patented a new model, The Standard Prisoptometer, on June 21, 1904. Edward Jackson's crossed cylinder technique of determining astigmatism was first detailed in the Transactions of the American Ophthalmological Society (1887)4:595-598. The convenience of Jackson's crossed cylinder lenses over the prisoptometer in weight, cost, portability and reliability meant that they were soon almost universally adopted.This is a rare item as few are known world wide.This instrument is an optometer, that is, a device to measure the refractive error of an eye. It is made of cast iron, steel, brass and glass. It contains a prism which could be rotated, and was used to view a disc or an object circle. The prism caused monocular doubling of the object circle and the separation of the two images varied as the prism rotated, depending on the astigmatism present. The axis of the astigmatism was indicated by the prisoptometer and trial lenses were used to determine the the magnitude of the spherical and cylindrical refractive errorImprinted:"DR CULBERTSON'S PRISOPTOMETER/ GENEVA OPTICAL COMPANY MAKERS, GENEVA, N.Y./ PATENTED SEPT, 21, 1886". Stamped "853" on eyepiece and lens mounting.optometry, prisoptometer, optometer, astigmatism, refractive error, refraction, culbertson

Hard cover book,The Clinical Use of Prisms Author: Ernest Edmund Maddox Publisher: John Wright & Co Date: 1907 5th Edition Further Information: Front cover & spine blue cloth title, publisher details and author name in gilt lettering.non-fictionThe subject volume The Clinical Use of Prisms; and the Decentring of Lenses is a seminal treatise on ophthalmic optics, binocular vision, and the correction of eye muscle imbalances (strabismus and heterophoria). The book covers two core clinical topics. Prismatic Refraction, how light bends through optical prisms, and how clinicians can use prisms to measure, diagnose, and relieve eye strain (asthenopia), double vision (diplopia), and misaligned line of sight. Decentring Lenses is the second and its focusing on the mathematical and practical rules for shifting the optical center of a spectacle lens relative to the patient's pupil. By decentring a standard spherical or cylindrical lens, allowing an optometrist or ophthalmologist to create an intentional "prismatic effect" without needing to grind a separate, heavy prism into the glassflagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, the clinical use of prisms, book, ernest f. maddox

Blue hard covered book with gold writing and illustrations on front cover, illustrations, 196 pages. Targetted to the general reader of the scientific principles of heat, light and sound topics include heat; light (including reflection and refraction); vision (including vision and optical illusions, the eye, chromatic aberration, spinning tops); optical illusions (including occular estimation, zollner's designs, the thaumatrope, phenakistoscope, zootrope, praxinoscope, the dazzling top); optical illusions cont. (including the talking head, ghost illusions); optical apparatus (including the eye, the streoscope, spectrum analysis, the spectroscope, the telescope and microscope, photography, dissolving views, luminous paint); spectral illusions (including a spectre, ghosts); acoustics (including the harmonograph); acoustics cont (including the topophone, the megaphone, the autophone, the audiphone, the telephone, the phonograph, the microphone). non-fictionscience, science class, scientific recreation series, light, heat, sound, ballarat ironworkers & polytechnic association

Trial frames are used to hold trial spectacle lenses in front of the eyes to establish the spectacle refraction. This unit is able to hold 3 lenses in front of each eye. It is very complex for its early date.This trial frame is a rare example of a very complex early design which has survived in good condition. Complex nineteenth century trial frame: double lens clip to front rotated by long control knob. Single downward pointing lens clip to back. Bridge height and extension adjustable. Variable inter-pupillary distance calibrated in inches. Slide extending curl sides. Eye rims stamped:'PAT NOV.6.94 & PAT JUNE25.95'. Sides stamped:'PAT APR.30.95'optometry, eye examination, refraction, trial frame, spectacles

Model eyes were used by students to practise skills of ophthalmoscopy and retinoscopy. This item shows more variety of fundus view and refractive state than most.This fine example is preserved in excellent condition, perhaps through lack of use. It is the most complex of the five model eyes in the collection.Cased metal model eye for teaching ophthalmoscopy and retinoscopy. 17 numbered interchangeable fundi illustrating various pathological conditions. Double cell lens holder in front can hold lenses for retinoscopy. Axis scale on front. 6 lenses provided to simulate various refractive states. Rotating disc changes between 3 pupil sizes. Model eye, fundi samples & lenses enclosed in snap closing wooden case, covered in black leatherette and lined with burgundy velvet.Inside case:'F.DAVIDSON & Co,/ 29 GREAT PORTLAND STREET,/ LONDON, W/ DUNN'S MODEL EYE'optometry, ophthalmology, model eye, teaching, ophthalmoscopy, retinoscopy

This case only includes spherical lenses and has no cylindrical lenses for correction of astigmatism. The lenses have no rims, which was unusual after 1900. The set appears to have had very little use as it is in excellent condition.This is a late example of a trial case comprising only spherical lenses. The trial frame is a very rare type.Small timber cased trial set of spherical lenses only. No rims on lenses. Case labelled with lens powers in dioptres and inches. Trial frame included of unusual design:each eye rim has a sprung top cover to secure lens in place. Nickel alloy. Fixed bridge stamped 62, tapered sides with loop ends. Also a lens handling tool (nickel alloy) to position a lens in front of patient's eye.Lens powers labelled in inches and dioptres. Trial frame bridge stamped '62'.optometry, lenses, refraction, trial case, trial set

This is the 1854 fourth edition of a book on diseases of the eye by William MacKenzie (1791-1868) first published in 1830. William MacKenzie was surgeon oculist in Scotland to Her Majesty (Queen Victoria), lecturer in the University of Glasgow and a surgeon in the Glasgow Eye Infirmary. This fourth edition appeared just after Helmholtz's invention of the ophthalmoscope, but Mackenzie did not at this stage have much understanding of the internal diseases of the eye. Nor did he properly understand refractive errors which were soon to be elucidated by the work of Donders. MacKenzie did however recognise the hardness of the eye as being an essential sign of glaucoma.This book is significant historically as it shows contemporary understanding of eye disease in the early nineteenth century. It is not rare as copies still turn up at book markets and also are held in other Australian institutions.This book, bound in full calf leather (probably later 19th Century) with 1107 pages including an index and is followed by a publisher's catalogue. It is the 1854 fourth edition of William MacKenzie's 'A practical treatise on the diseases of the eye' first published in 1830. It has a long (32 pages) introductory section on the anatomy of the eye by Thomas Wharton Jones, FRS. There are 27 chapters on eye disease. Chapter 24 is on refractive errors and presbyopia.eye, ocular anatomy, ocular disease