OPTICS II

SHE Level 1
SCQF Credit Points 20.00
ECTS Credit Points 10.00
Module Code M1B522298
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

-359 Basic properties of light-Basic geometry; b7 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 -425 -359b7 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; Swaine's criterion. 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 successful completion of this module students should be able to:1. demonstrate a knowledge and understanding of geometrical optical principles 2. demonstrate a theoretical and practical knowledge of instruments and optical bench methods for determining optical constants. 3. derive and use appropriate formulae to solve problems relating to refraction at plane and curved surfaces, lens systems and optical instruments. 4. draw ray diagrams to illustrate optical principles of various instruments. 5. understand wave and particle nature of light, properties of light waves.6. understand diffraction effects on visual acuity and visual resolution 7. demonstrate a knowledge and understanding of the principles involved in the optics of vision8. derive and apply formulae to solve problems relating to image formation and optical correction of the eye. 9. draw ray diagrams to illustrate the formation of retinal images in corrected and uncorrected eyes. 10. be able to communicate and explain basic scientific systems and the optics of vision to the lay public.11. demonstrate observational and record/report writing skills. 12. 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 and data analysis skills. Coursework will be a mixture of both formative and summative class tests. The tutorials will enable the students to develop problem-solving skills and will provide an opportunity for group discussion and feedback.

Indicative Reading

Books Rabbetts RB. (2007) Bennett & Rabbetts Clinical Visual Optics 4 th Edition Butterworth Heinemann Atchison, DA and Smith, G. (2000) Optics of the Human Eye, Butterworth Freeman, MH & Hull, SCC. (2003) Optics, (11th Ed.), Butterworths. Keating, MP. (1998) Geometric, Physical and Visual Optcs, Butterworths Serway, RA. Physics for Scientsts and Engineers Saunders 2003 Smith, G & Atchison, DA. (1997) The Eye and Visual Optical Instruments Tunnacliffe, A & Hirst J. (1996) Optics (2nd Ed.) ABDO Tunnacliffe, A (1991) Worked Problems on Optics (2nd Ed.) ABDO Tunnacliffe AH (1993) Introduction to Visual Optics. 4 th Edition iBooks Bullimore M (2019) Geometric Optics - available on iBooks Fullard R (2019) Visual Optics- available on iBooks

Transferrable Skills

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

Module Structure

Activity Total Hours
Lectures (FT) 35.00
Practicals (FT) 18.00
Assessment (FT) 5.00
Independent Learning (FT) 102.00
Tutorials (FT) 40.00

Assessment Methods

Component Duration Weighting Threshold Description
Coursework 1 n/a 50.00 35% Trimester 1 class test
Coursework 2 n/a 50.00 35% Trimester 2 class test