BOBO022 Spectacle optics

Faculty of Medicine
Spring 2013
Extent and Intensity
2/0. 3 credit(s). Type of Completion: zk (examination).
Teacher(s)
prof. RNDr. Radim Chmelík, Ph.D. (lecturer), doc. MUDr. Svatopluk Synek, CSc. (deputy)
Guaranteed by
prof. RNDr. Radim Chmelík, Ph.D.
Department of Optometry and Orthoptics – Departments of Non-medical Branches – Faculty of Medicine
Contact Person: Anna Petruželková
Supplier department: Department of Optometry and Orthoptics – Departments of Non-medical Branches – Faculty of Medicine
Course Enrolment Limitations
The course is only offered to the students of the study fields the course is directly associated with.
Course objectives
The course teaching is based on the fundamentals of geometrical optics, which are applied to eye as multi element optical system, which may be affected by various refractive errors (myopia, hyperopia, presbyopia, astigmatism, anisometropia, aniseikonia, aphakia). The aim of the course is to elucidate the effect of proper spectacle lenses as well as the method of their technical parameters determination for individual refractive errors.
Syllabus
  • Spectacle optics I. 1. Fundamentals of geometrical optics for spectacle optics (sign convention, refraction at a spherical surface, Gauss’ lens formula, system of refractive surfaces in the paraxial approximation, tabular calculations, the vertex power). 2. Imaging by the system of two centred optical surfaces in the paraxial space (cardinal points and planes of an optical system and their positions, transversal, longitudinal (axial) and angular magnification, the Helmholtz-Lagrange law, construction of image, vergence of a light pencil). 3. Gullstrand’s schematic eye (description and calculation of the corneal, lenticular and overall system of the schematic eye in the paraxial space, basic parameters and positions of cardinal points), real values of optical parameters of eye, alternative eye models. 4. Eye anatomy (overview, retina, photoreceptors, fundamental axes), photopic and scotopic vision, retinal image size, maximum eye resolution. 5. Visual acuity and optotypes (definition of visual acuity, dependence on age, basic parameters of optotypes, Snellen chart, optotype size gradation, LogMAR and VAR scales, ETDRS and cRLM charts, general requirements stressed on optotypes, angular and coincidence visual acuity) 6. Emmetropic, myopic and hyperopic eye. Far point, near point, axial refraction, accommodation interval, accommodation amplitude, expressions for individual ametropias, principle of ametropia correction. 7. Myopic eye. Classification of myopia, etiology & symptoms, correction, recalculation of the vertex power of a spectacle lens on the change of its distance from a cornea, retinal image size. 8. Hyperopic eye. Classification of hyperopia, etiology & symptoms, correction, recalculation of the vertex power of a spectacle lens on the change of its distance from a cornea, retinal image size. 9. Aphakic eye. Imaging by an aphakic eye. Correction of aphakia by a spectacle lens, by a contact lens, and by an intraocular lens. 10. Nature of the axial refraction with respect to eye length and to optical system power. Axial and system ametropia, emmetropic state of eye, dependence of aniseikonia on axial refraction. Spectacle optics II 1. Accommodation (accommodation interval and amplitude, dependence of accommodation on the position of object point, mechanism of accommodation, the Purkynie experiment, change of Gullstrand’s eye parameters during accommodation, description of accommodation in alternative eye model, accommodation measurement, the Duane graph). 2. Analysis of accommodation process (external and internal accommodation effect, Graef’s factor, the effect of a distance-vision correction lens on accommodation for myopia and hyperopia). 3. Correction of presbyopia (basis of presbyopia, technical possibilities of its correction, determination of addition from the position of a main working point, correction of presbyopia and intervals of sharp vision for emmetropic, myopic and hyperopic patients). 4. Spectacle lenses (bi-, plan-, periscopic, menisci, calculation of powers and radii of surfaces). 5. Single-point focus lenses (optical aberrations of spectacle lenses, field curvature and Petzval surface, Petzval sum, effect of field curvature at eye rotation, astigmatic pencil, tangential and sagittal plane and pencil of rays, focal lines, calculation of a single-point focus lens, the Tscherning ellipse, design of a thick single-point focus lens, possibilities of realization of single-point focus lenses, the Percival solution). 6. Aspheric spectacle lenses. Aberration correction by means of an aspheric surface. 7. Basic properties and parameters of spectacle lenses materials, chromatic aberration. 8. Prismatic effect (deviation, prismatic effect, image shift, orientation of base, prismatic effect of a lens, the Prentice rule) 9. Bifocal spectacle lenses (manufacture requirements, one-piece (grinded) bifocals, conditions for the zero image jump in bifocals, accommodation intervals), trifocal spectacle lenses (main working points, accommodation intervals), fused bifocals (calculation of surface radii, of refractive index, image jump). 10. Progressive power spectacle lenses (principle, design and manufacture, iso-power and iso-cylinder lines, sources of astigmatism, definition and width of progressive power corridor, soft and hard type of lens). 11. Lenticular lenses. Prism correction. 12. Eye astigmatism (etiology, classification, & correction of eye astigmatism). 13. Cylinder and toric spectacle lenses. Conversion of astigmatic corrections.
Literature
  • A. H. Tunnacliffe: Introduction to Visual Optics. ABDO College, Canterbury 2004.
  • R. Baštecký: Praktická brýlová optika. R+H Optik, Praha 1997.
  • 1. Brýlová optika pro SZŠ, Mgr.Rutrle M, IDVPZ Brno, 1993
  • BALÍK, J. and J. BOBEK. Technický sborník oční optiky. Edited by J. Polášek. 2. vyd. Praha: Oční optika, 1975, 579 s. info
Teaching methods
Lecture completed by exercises that immediately follow the lecture subject matter.
Assessment methods
2 written tests take place during each of both semesters; 50 % of the maximum total score is necessary to pass. Oral examination consists from 2 topics. The resulting classification is calculated as the average of the written tests score (weight ca 1/3) and of the oral exam score (weight ca 2/3).
Language of instruction
Czech
Further Comments
The course is taught annually.
The course is taught: every week.
The course is also listed under the following terms Spring 2000, Spring 2001, Spring 2002, Spring 2003, Spring 2004, Spring 2005, Spring 2006, Spring 2007, Spring 2008, Spring 2009, Spring 2010, Spring 2011, Spring 2012.
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