FOUNDATIONS OF OPTICS

SHE Level 1
SCQF Credit Points 40.00
ECTS Credit Points 20.00
Module Code M1B525788
Module Leader Niall Strang
School School of Health and Life Sciences
Subject Vision Sciences
Trimester
  • A (September start)-B (January start)

Summary of Content

This module will develop a knowledge and understanding of the principles of refraction and reflection at plane and curved surfaces and will apply these principles to the study of various optical systems. This module will give students the theoretical background to understand the basic principles of physical optics and their specific relevance to practice and the human visual system. Building on these theoretical frameworks it will then introduce and develop an understanding of vision and the eye's optical system. It will provide an understanding of the principles of image formation and the optical correction of the eye. This will provide the basis for the more detailed consideration of ophthalmic lenses, instruments and appliances to be encountered in subsequent modules throughout the programme. The nature of the report writing will also encourage the development of communication skills with the lay public.

Syllabus

Basic properties of light-Basic geometry; -359b7 Electromagnetic spectrum; b7 Light sources; b7 Wave nature of light; b7 Concept of vergence; b7 Rectilinear propagation: shadows, pinhole cameras. b7 Refraction at plane surfaces: Refractive index, laws, image formation (real and apparent depth and measurement of refractive index), critical angle and uses of total internal reflection, refraction by rectangular glass block. b7 Prisms: Thick prisms: deviation, minimum deviation; Prism spectrometer (laboratory session); Thin prisms: deviation, prism dioptre, uses; Image formation b7 Refraction at curved surfaces: Paraxial approximation; Sign convention; Fundamental paraxial expression; Power; Vergence, Reduced vergence, Principal foci; Extended objects; Construction rays; Transverse magnification; Object at infinity; b7 Refraction through a series of spherical curved surfaces: Thin lenses-Conjugate foci formula; Principal foci; Extended objects; Construction rays; Types of images; Transverse magnification; Measurement of focal length: Autocollimation, Conjugate foci and Displacement methods; b7 Prismatic effects of thin lenses; b7 Introduction to chromatic aberration; b7 Separated thin lenses: introduction to lens systems and concept of equivalent power. b7 Reflection at plane surfaces: Diffuse and specular reflection, laws, types of plane mirror, deviation by fixed & rotating mirror, image formation, field of view, uses. b7 Reflection at curved surfaces; Action of convex and concave mirrors, spherical aberration and caustic curve, conjugate foci expression, power, principal foci, transverse magnification, construction rays, field of view. b7 Measurement of radius of curvature and focal length of mirrors: optical bench methods. b7 Principles of Optical Instruments: Accommodation; Visual angle; Magnifying power; Simple magnifier; normal and near-point adjustment; Compound microscope: normal and near-point adjustment; Refracting telescopes: Astronomical, Terrestial, Binoculars; Galilean; b7 Stops in optical systems: aperture stop, entrance and exit pupils; field stop, vignetting; Stops applied to Astronomical and Galilean telescopes. Stops applied to cameras. b7 Gaussian Theory-System of two separated thin lenses: vertex powers, principal planes and equivalent power, cardinal points, construction rays, conjugate foci expression, Newton's expression. Thick lenses: vertex powers, equivalent power, cardinal points, construction rays, conjugate foci expression, Newton's expression. Multi-refracting system. -425 -359b7 Light and wave properties: harmonic waves, travelling waves, the superposition principle, standing waves. b7 Interference: Young's Double Silt, amplitude splitting interferometers, interference from thin films, anti-reflection coatings, dielectric mirrors, Michelson interferometer. b7 Diffraction: Huygens-Fresnel principle, Fraunhoffer diffraction, circular aperture, resolution, diffraction gratings. b7 Polarised Light: Introduction, Law of Malus', Brewster's angle, light scattering, states of polarization. b7 Structure of the Human Eye b7 Location, size and basic functions of the principle elements of the eye and visual pathway. b7 Vision and Visual acuity, detection, discrimination, resolution and recognition; Visual acuity and Snellen's principle. b7 Schematic Eye: Concept of reduced eye; Historical development including work of Listing, Helmoltz, Tscherning, Gullstrand & Emsley; Cardinal points; Gullstrand's schematic eyes I and II; Gullstrand-Emsley eye; Entrance and Exit pupils; Derivation of standard reduced emmetropic eye. b7 Retinal Image Formation; Retinal & optical images; Chief ray; Basic retinal image size; Blur circle; Projected blur; Total retinal image size; Pinhole and Scheiner discs; Blur ratio. b7 Spherical Ametropia and astigmatism; Myopia, Hypermetropia; Axial and refractive ametropia; Ocular refraction; Dioptric length; Far point; Spectacle refraction and vertex distance; Image formation in the corrected eye; Spectacle magnification; Relative spectacle magnification; Knapps rule; retinal image size ratio; Thick lens calculations; -359b7 Anisometropia and Aniseikonia: clinical implications, iseikonic lens. b7 Astigmatism Regular and Irregular astigmatism; Classification by type, axis orientation & degree; Ocular astigmatism; Focal lines and the circle of least confusion; Blur ellipses; Spectacle astigmatism; Image formation in the corrected and uncorrected eye; Cylinder effectivity in near vision. b7 Accommodation: Ocular accommodation; Near point; Range of accommodation; Spectacle accommodation; Presbyopia; Near vision prescriptions; Depth of field; Depth of focus. Aphakia. Optical consequences of aphakia. b7 Calculations of refractive error, optical correction and image formation based on Gullstrand-Emsley eye; b7 Clinical implications of optical correction; Image magnification summary. Image formation and Spectacle magnification; Afocal contact lens; Comparisons with spectacle correction: image size, prismatic effects, accommodation. b7 Spatial and temporal induction, entoptic phenomena, catoptric and catadioptric images.

Learning Outcomes

On completion of this module students should be able to: 1. demonstrate a knowledge and understanding of geometrical optical principles including refraction and reflection at plane and curved surfaces. 2. demonstrate a knowledge and practical understanding of the principles of optical instruments. 3. demonstrate a basic understanding of the effects of stops within optical systems. 4. demonstrate a theoretical and practical knowledge of instruments and optical bench methods for determining optical constants. 5. understand and apply Gaussian theory to optical systems including two separated thin lenses in air, thick lenses and multi-refracting systems.6. derive and use appropriate formulae to solve problems relating to refraction and reflection at plane and curved surfaces, lens systems and optical instruments. 7. draw ray diagrams to illustrate optical principles of various instruments. 8. understand wave and particle nature of light, properties of light waves and the nature of polarised light.- understand clinical applications and significance of interference of light waves 9. understand diffraction effects on visual acuity and visual resolution 10. demonstrate a knowledge and understanding of the principles involved in the optics of vision11. derive and apply formulae to solve problems relating to image formation and optical correction of the eye. 12. demonstrate observational and record/report writing skills. 13. demonstrate adequate foundation knowledge to enter into clinical areas for which knowledge of geometrical optics and visual-optical function is required.

Teaching / Learning Strategy

The module will consist of lectures, demonstrations, practicals and tutorials (including e-learning facilities). The laboratory work will encourage the students to gain a practical understanding of the subject and to develop observational, data analysis and data management skills. Coursework will be a mixture of both formative and summative class tests and data analysis sessions. The tutorials will enable the students to develop problem-solving skills and will provide an opportunity for group discussion and feedback.

Indicative Reading

-359 Keating, MP. (1998) Geometric, Physical and Visual Optics, Butterworths Tunnacliffe, AH & Hirst, J. (1996) Optics 2nd Ed, ABDO Tunnacliffe, A Worked Problems on Optics (2nd Ed.) ABDO, 1991 Freeman, MH & Hull, SCC., Optics, (11th Ed.), Butterworths, 2003. Serway, RA. Physics for Scientists and Engineers Saunders 2003 Halliday, D, Resnick, R, & Krane, KS. Physics vol 2 (5th Ed.) John Wiley 2001 Atchison, DA and Smith, G. Optics of the Human Eye, 2000, Butterworth Rabbetts, RB. Clinical Visual Optic (4th Ed), 2007 Tunnacliffe, AH. Introduction to Visual Optics (4th Ed), 1993 Smith, G & Atchison, DA. The Eye and Visual Optical Instruments 1997 Kierl, A & Christie, C. Clinical Optics & Refraction 2007 -358 i Books Geometric Optics - Mark Bullimore - available via iBooks Visual Optics - Roderick Fullard - available via iBooks -359

Transferrable Skills

Data analysis; problem solving; numeracy; investigative techniques; communication skills

Module Structure

Activity Total Hours
Practicals (FT) 28.00
Independent Learning (FT) 242.00
Assessment (FT) 8.00
Lectures (FT) 68.00
Tutorials (FT) 54.00

Assessment Methods

Component Duration Weighting Threshold Description
Exam (Exams Office) 2.00 50.00 35% Unseen written paper for Visual Optics and Applied Optics (VO and AO)
Coursework 1 n/a 50.00 35% Coursework Assessment