Optics of the Spectacle LensesLaajuus (5 cr)

Objective

Students are able to
• describe and solve problems by calculating and drawing a human eye as an optical system
• calculate power effect in different vertex distance
• calculate, measure and describe the effect of prism on spectacle lenses and the elimination of unwanted prism effect and use of that in the purpose meaning
• calculate and describe the magnification effect of spectacles and design solutions in the case of aniseiconic cases

Themes are sphero-cylindrical lenses, thin prisms, prismatic effect and the manipulation of lens form and setting to obtain the desired control of prismatic effect.

Content

Eye models and sphero-cylindrical lenses
o ametropias and refraction of the principal meridians
o sphero-cylindrical lenses and the location of foci, image planes, principal meridians, least blur confusion
o dioptric distributions in lenses, also between principal meridians
Lens prismatic effect
o Prentice formula
o manipulation of lens form and setting to obtain the desired control of prismatic effect horizontal and vertical meridian
o vertical prism effect
Schematic eye models:
• Dioptric components
• Cardinal points, entrance and exit pupils
• Ametropia: far point, near point, correction
• Accommodation: amplitude and effectivity
• Astigmatism, including correction
• Retinal image size, spectacle magnification, and relative spectacle magnification
• Apertures
• Entrance and exit pupil size and location
Optics of the eye:
• Characteristics of components (curvature, thickness, separation, refractive indices, and axial length)
• Reference angles and axes
• Retinal image size
• Optical function of the pupil – depth of field
Spectacle lenses:
• geometry of the lens surface: aspherical and atoric lenses
• Power effect distance and near and vertex distance
• spectacle magnifications
o shape and power factors
o relative spectacle magnifications
o iseiconic lenses
• lens prism and prismatic effect
o thickness differences in lens by the prism
o combination of thin prisms
o resolution of an oblique prism into horizontal and vertical components, oblique prism
o prism effect in near distances
• vertical prism eliminations aniseiconic cases
o Slab off, prism segment, Fresnell prism, taking account of height
• lens induced problems; aberrations, weight, thickness, limits of field, secondary images, magnification, jump and displacement in spherical and sphero-cylindrical lenses

Assessment criteria, satisfactory (1)

Student is able to:
- Display learning in core content
- Use individual professional concepts correctly
- Find information for a specific situation
- Distinguish between non-theoretical and theoretical information
- Act in individual professional situations as instructed
- Display learning in his professional field
- Show that he has achieved the targets for core competence
- Follow safety instructions
- Display learning in the ethical principles of his professional field
- Operate as a member of a student group

Assessment criteria, good (3)

Student is able to:
- Display an understanding of concepts and professional knowledge in the field
- Assess and limit the amount of information needed
- Operate well in typical professional duties and contexts
- Operate in a multicultural environment
- Operate safely
- Act according to professional ethics
- Operate in a student group

Assessment criteria, excellent (5)

Student is able to:
- Use concepts and knowledge in his field systematically
- Assess and use various information sources
- Apply professional information in professional assignments
- Work in various duties in a variety of operating environments
- Act independently and responsibly in professional contexts
- To take safety issues into consideration in his action
- Argue his choices on the basis of professional ethics
- Organise the activities of a group of students

Assessment criteria, approved/failed

Student is able to:
- Display learning in core content
- Use individual professional concepts correctly
- Find information for a specific situation
- Distinguish between non-theoretical and theoretical information
- Act in individual professional situations as instructed
- Display learning in his professional field
- Show that he has achieved the targets for core competence
- Follow safety instructions
- Display learning in the ethical principles of his professional field
- Operate as a member of a student group