The evidence guide provides advice on assessment and must be read in conjunction with the Performance Criteria, Required Skills and Knowledge, the Range Statement and the Assessment Guidelines for this Training Package.

Critical aspects for assessment and evidence required to demonstrate this competency unit:

The individual being assessed must provide evidence of specified essential knowledge as well as skills

Observation of actual or simulated workplace performance is essential for assessment of this unit

Consistency of performance should be demonstrated over the required range of situations relevant to the workplace

Where, for reasons of safety, space, or access to equipment and resources, assessment takes place away from the workplace, the assessment environment should represent workplace conditions as closely as possible

Context of and specific resources for assessment:

Resources essential for assessment include:

Access to an optical appliance manufacturing workplace

Method of assessment

Observation in the work place (if possible)

Written assignments/projects or questioning should be used to assess knowledge

Case study and scenario as a basis for discussion of issues and strategies to contribute to best practice

Access and equity considerations:

All workers in the health industry should be aware of access and equity issues in relation to their own area of work

All workers should develop their ability to work in a culturally diverse environment

In recognition of particular health issues facing Aboriginal and Torres Strait Islander communities, workers should be aware of cultural, historical and current issues impacting on health of Aboriginal and Torres Strait Islander people

Assessors and trainers must take into account relevant access and equity issues, in particular relating to factors impacting on health of Aboriginal and/or Torres Strait Islander clients and communities

Related units:

It is recommended that this unit be delivered and assessed in conjunction with:

HLTOPT406B Edge and fit ophthalmic appliances

HLTOPT407C Apply surface coatings to ophthalmic lenses

This describes the essential skills and knowledge and their level required for this unit.

Essential knowledge:

The candidate must be able to demonstrate essential knowledge required to effectively do the task outlined in elements and performance criteria of this unit, manage the task and manage contingencies in the context of the identified work role

This includes knowledge of:

Astigmatic lenses including:

how to perform calculations related to the application of astigmatic lenses in optical prescriptions

nature of astigmatism

the difference between cylindrical and astigmatic lenses

various forms of astigmatic lenses

Drilled rimless frames including mounts and rimless types and equipment needed

Filter and tinted lens processes including:

Australian Standards

plastic lens tinting including dyes and tint types, equipment, preparation, problems and solutions

transmission testing including equipment and instrumentation, equipment limitations and Australian Standards

Frame measurement systems including boxing and datum

Glazing techniques

Impact resistant safety lenses including:

advantages and disadvantages

Australian Standards for both general purpose and industrial use

evaluation of materials including glass, CR39, higher index plastics, polycarbonate and laminates

impact resistance

impact testing requirements, conditions and procedures

principles and processing of thermal and chemical toughening

problems and special lens requirements

Lens thickness including:

affect of prism on lens thickness

determining meridian thickness and oblique meridian thickness

how to perform calculations related to the application of lenses in optical prescriptions

nature of curve variation factor and sagittal thicknesses

the different affects of lens indices on thickness

Light including:

calculation of angles of incidence, refraction, deviation and critical angles

contemporary theories of light

how light is propagated and explain how commonly observed effects may occur

various light-induced phenomena

continued ...

Essential knowledge (contd):

Multifocal and progressive lenses including:

appropriate formulae when performing calculations related to multifocal and progressive lenses

calculation of fused segment and thickness allowance for manufacturing

determining addition powers

determining powers from radii

determining the prismatic effect of multifocal and progressive lenses

differences between bifocals, trifocals progressives, and their methods of manufacturing

differences between fused and solid multifocals

differentiating styles and types of progressive lenses

the range of multifocal and progressive lenses available

Ophthalmic prism including:

effects of ophthalmic prism upon the eyes, and the need for
ophthalmic prism in prescriptions

solving by both calculation and graphical methods, a variety of prism
problems

the relationship between lens power, decentration and prism

the use of a tangent scale to measure ophthalmic prism

Relevant Australian Standards

Scope of metal and plastic frame material including heating, manipulation, adjusting, handling and repair

Spherical lenses including:

concepts of vergence and demonstration of its use in optical calculations

how to construct diagrams to illustrate image formation using simple ray-tracing techniques

refractive effects of a lens as the sum of its two surface powers

refractive properties of spherical lens surfaces

The properties of lens

The use of impact resistant protective lenses

Types of ophthalmic lenses and spectacle frames and their performance characteristics

Vacuum coatings including:

absorptive (tinted) coatings

handling, cleaning and care of coatings

manufacturing processes

multiple layer AR coatings

single AR coating

surface reflections and ghost images

Essential skills

It is critical that the candidate demonstrate the ability to effectively do the task outlined in elements and performance criteria of this unit, manage the task and manage contingencies in the context of the identified work role

This includes the ability to:

Calculate minimum size uncut (MSU):

MSU using centration chart and by calculation to allow for PD and decentration for prism

Correctly and accurately use a focimeter (lensmeter) including:

correct neutralisation

determination of powers

determination of axes

determination of prism

determination of centration

determination of additions

Complete semi-finished lens surface protection

Generate lens surfaces

Hand edge using both hand bevelling techniques and safety chamfering

Handle glass and plastic lens material

Handle metal and plastic frame material

Interpret grind card calculations

Take into account opportunities to address waste minimisation, environmental responsibility and sustainable practice issues

Transpose a prescription

Undertake a surface inspection

Undertake digital fame tracing

Undertake lay out and blocking

Undertake material selection

Undertake surface curve finishing

Use appropriate techniques to inset lens and fit frames

Use problem solving techniques:

reducing unwanted vertical and/or horizontal prism

rectifying off-axis lenses

The Range Statement relates to the unit of competency as a whole. It allows for different work environments and situations that may affect performance. Add any essential operating conditions that may be present with training and assessment depending on the work situation, needs of the candidate, accessibility of the item, and local industry and regional contexts.

Prescriptions may include:

Lens order including electronic, fax, telephone

Optometrist prescription

Basic mathematical operations mustinclude but is not limited to:

Base curve

Front curve

Prism

Lens power

Thickness

Cut out

Minimum size uncut

Lens material includes:

Mineral material

Organic material

Frame material includes

Metals

Plastics

Manufacture of higher powered prescription lenses may include:

Surfacing techniques for higher prescription lens surfaces

Surfacing techniques for higher prisms, prescribed and decentered prisms

Routine maintenance may include:

Regular checking of equipment

Replacing consumables

"in-house" cleaning and servicing of equipment according to manufacturer's guidelines

Periodic servicing by qualified or manufacturer approved technician

Equipment faults or problems may be identified or anticipated by:

Routine checking of equipment

Preparation of a maintenance program

Encouraging feedback from work colleagues

Regular back-ups of data

Keeping a log book of detected faults

Regular occupational health and safety inspections

Checking that repairs have been carried out

Basic lens treatment may include:

Tinting including colour and UV

Glass toughening