Standard

Posted: 03/18/08

R State Standard         £ Institutionally Developed          College: N/A

OPD 112 – Eyewear Lens Selection and Dispensing

Course Description

This course continues students' study of eyewear dispensing techniques. Emphasis is placed on gaining clinical experience in providing service to the eyewear consumer. Topics include: prescription lens materials; lens positioning; multifocal lenses; absorptive lenses; special lens coatings; prescription lens selection; lens finishing; use and care of eyewear; matching lenses to consumer needs; and optical, physiological, and psychological problems.

Competency Areas

Hours

Prescription Lens Materials

Class

2

Lens Positioning

D. Lab

4

Multifocal Lenses

P. Lab/O.B.I.

6

Absorptive Lenses

Credit

6

Special Lens Coatings

 

 

Prescription Lens Selection

 

 

Lens Finishing

 

 

Use and Care of Eyewear

 

 

Matching Lenses To Consumer Needs

 

 

Optical, Physiological, and Psychological Problems

 

 

 

Prerequisite:

OPD 109

Corequisite:

 

 

Course Guide

 

Competency

After completing this section, the student will be able to:

Hours

Class

D.Lab

P.Lab/

O.B.I.

PRESCRIPTION LENS MATERIALS     

2

4

6

History

Discuss the discovery of glass and the historical development of the glassmaking process.

 

 

 

 

Describe modern glassmaking techniques.

 

 

 

 

Compare the batch method to the continuous flow method.

 

 

 

 

Discuss the historical development of plastic lens materials.

 

 

 

 

Compare the advantages and disadvantages of thermoplastic and thermosetting materials.

 

 

 

Lens materials

Identify the different lens materials used for prescription lenses.

 

 

 

 

Describe the index of refraction and specific gravity for each lens material.

 

 

 

 

Compare the advantages and disadvantages of various lens materials.

 

 

 

 

Identify specific uses for high-index and impact-absorbing lenses.

 

 

 

LENS POSITIONING    

2

4

6

Corrected curve lenses

Identify the six aberrations of lenses and describe common lens design difficulties.

 

 

 

 

Discuss the historical use of flat-form lenses.

 

 

 

 

Describe the development of corrected curve lenses from meniscus and periscopic forms to modern minus-cylinder lenses.

 

 

 

Base curves

Discuss the use of base curves to minimize lens aberrations in corrected curve lens design.

 

 

 

 

Select the proper base curve for a given lens prescription transmittance.

 

 

 

 

Describe common complaints and solutions for base curve selection errors.

 

 

 

Pantoscopic angle

Discuss the roles of pantoscopic, orthoscopic, and retroscopic angle in corrected curve lens design.

 

 

 

 

Describe the proper pantoscopic angle in relation to the face plane and the height of the optical center.

 

 

 

 

Calculate the vertical placement of the optical center for a given amount of pantoscopic angle.

 

 

 

Face-form (panabolic curve)

Discuss the roles of positive and negative face-form in corrected curve lens design.

 

 

 

 

Describe proper face-form in relation to the decentration of the optical center.

 

 

 

 

Calculate the amount and type of face-form for a given amount of decentration.

 

 

 

Prism

Describe the unwanted prismatic effects created by improper optical center placement.

 

 

 

 

Identify the ANSI tolerances for vertical and horizontal prism.

 

 

 

 

Calculate the amount of unwanted prism created by improper optical center placement.

 

 

 

MULTIFOCAL LENSES

2

4

6

Segment

Identify the different shapes, sizes, and styles of multifocal segments.

 

 

 

 

Discuss the advantages and disadvantages of each type of multifocal segment.      

 

 

 

 

Describe the common location of the segment optical center for each multifocal style.

 

 

 

Progressive addition lenses

Identify the common styles of progressive addition lenses.

 

 

 

 

Discuss the advantages and disadvantages of spherical versus aspherical designs.

 

 

 

 

Describe the concept of the progressive corridor.

 

 

 

 

Describe the correct positioning, ordering, fitting, and verification procedures for progressive addition lenses.

 

 

 

 

Discuss the advantages and disadvantages of progressive addition lenses versus conventional multifocals.

 

 

 

Image jump

Discuss the concept of image jump through multifocal lenses and its effects upon the wearer.

 

 

 

 

Identify multifocal segment styles that minimize or eliminate image jump for a given prescription.

 

 

 

 

Calculate the amount of image jump for a given prescription and multifocal segment.

 

 

 

Object displacement

Discuss the concept of object displacement through multifocal lenses and its effects upon the wearer.

 

 

 

 

Identify multifocal segment styles that minimize or eliminate object displacement for a given prescription.

 

 

 

 

Calculate the amount of object displacement for a given prescription and multifocal segment.

 

 

 

 

Vertical prism imbalance

 

 

 

 

Discuss vertical prism imbalance through multifocal lenses and its effects upon the wearer.

 

 

 

 

Identify lens prescriptions that contain vertical prism imbalance.

 

 

 

 

Describe six methods for reducing or eliminating vertical prism imbalance.

 

 

 

 

Calculate the amount of vertical prism imbalance for a given multifocal prescription.

 

 

 

Vertex distance

Define vertex distance and describe how it is measured.

 

 

 

 

Describe how the dioptric power of a lens changes when the vertex distance of the spectacles differs from the vertex distance given in the prescription.

 

 

 

 

Calculate dioptric power changes and the compensated power of lenses for changes in vertex distance.

 

 

 

ABSORPTIVE LENSES            

2

4

6

Metallic oxides

Identify metallic oxides commonly used to color glass lenses.

 

 

 

 

Describe the process to add metallic oxides to glass lenses.

 

 

 

 

Describe the concept of uniform density films.

 

 

 

 

Discuss the advantages and disadvantages of absorptive and uniform density lenses.

 

 

 

Photochromic lenses

Describe the properties of lenses containing silver halide crystals within the lens matrix.

 

 

 

 

Describe the responses of photochromic lenses to UV, IR, and visible light.

 

 

 

 

Describe the response of photochromic lenses to temperature changes.

 

 

 

 

Discuss the concept of exposure memory.

 

 

 

 

Contrast the optical and thermal methods of bleaching photochromic lenses.

 

 

 

 

Discuss the advantages and disadvantages of photochromic lenses.

 

 

 

SPECIAL LENS COATINGS                             

2

4

6

Scratch resistance

Identify lens coating materials which are scratch resistant.

 

 

 

 

Describe the process used to apply scratch resistant coatings to lenses.

 

 

 

 

Discuss the advantages and disadvantages of scratch resistant coatings.

 

 

 

Antireflection

Identify lens coating materials which are antireflective.

 

 

 

 

Describe the process used to apply antireflective coatings to lenses.

 

 

 

 

Calculate the thickness and index of refraction of the antireflective film for a given lens material.

 

 

 

 

Discuss the advantages and disadvantages of antireflective lens coatings.

 

 

 

Tint

Identify lens tinting materials used to color lenses for cosmetic purposes.

 

 

 

 

Describe the process used to apply cosmetic color coatings to lenses.

 

 

 

 

Discuss the advantages and disadvantages of cosmetic color coatings.

 

 

 

 

Identify lens coating materials for ultraviolet protection.

 

 

 

 

Describe the process used to apply ultraviolet protection coatings to lenses.

 

 

 

 

Discuss the advantages and disadvantages of ultraviolet protection coatings.

 

 

 

 

Identify lens coating materials which provide special transmittance qualities.

 

 

 

 

Describe the process used to apply special transmittance coatings.

 

 

 

 

Discuss the advantages and disadvantages of special transmittance coatings.

 

 

 

PRESCRIPTION LENS SELECTION     

2

4

6

Material selection

Analyze individual consumer needs in the areas of lens parameters, intended use, prescription, and breakage resistance requirements.

 

 

 

Multifocal

Determine the type of lens and seg style by analyzing consumer's vocational and avocational needs.

 

 

 

Wearer's characteristics

Identify consumer height, posture, age, near vision work area, near vision habits, mobility, physical limitations, and general health to match lenses to consumer needs.

 

 

 

LENS FINISHING

2

4

6

Parameters

Describe the visual and optical effects of the following lens parameters: base curve, power, sign, axis, centering, multifocal height, size, fit, tilt, index of refraction, lens thickness, weight, and prismatic effect.

 

 

 

Equipment

Operate lens finishing equipment to produce lenses with parameters that conform to ANSI standards.

 

 

 

USE AND CARE OF EYEWEAR

2

4

6

Cleaning

Instruct consumers in the proper methods of cleaning frames.

 

 

 

 

Instruct consumers in the proper methods of cleaning lenses.

 

 

 

 

Instruct consumers in the special cleaning methods for coated lenses.

 

 

 

Storage

Identify various storage methods and containers for eyewear.

 

 

 

 

Instruct consumers in the proper methods of storing eyewear.

 

 

 

Safety

Instruct consumers in methods of preventing lenses from fogging during climate changes.

 

 

 

 

Examine lenses to determine if scratches are deep enough to weaken hardened lenses.

 

 

 

 

Advise consumers on frame and lens types and styles required for specific occupations.

 

 

 

Eyewear use

Instruct consumers in exposure memory and break-in methods for photochromic lenses.

 

 

 

 

Instruct consumers in the proper use of progressive addition lenses for distant, intermediate, and near visual tasks.

 

 

 

 

Instruct consumers in the proper use of occupational, specialty, and absorptive lenses.

 

 

 

MATCHING LENSES TO CONSUMER NEEDS              

2

4

6

Lenses

Describe the materials and types of single vision lenses available.

 

 

 

 

Describe the materials and types of multifocal lenses available.

 

 

 

 

Describe the types of tints, coatings, and surface treatments available for lenses.

 

 

 

Specialty lenses

Describe the types of lenses, tints, and coatings best suited for high- minus and high-plus prescriptions.

 

 

 

 

Describe the types of lenses, tints, and coatings designed for specific occupations, sports, hobbies, lifestyle, and recreational activities.

 

 

 

 

Describe the types of lenses, tints, and coatings designed for aphakic and pseudophakis lens prescriptions.

 

 

 

 

Describe the types of lenses, tints, and coatings designed for retinitis pigmentosa and macular degeneration.

 

 

 

Consumer's lifestyle

Analyze a consumer's lifestyle.

 

 

 

 

Inform consumer of eyewear options and assist in selecting the type and style of eyewear.

 

 

 

OPTICAL, PHYSIOLOGICAL, AND PSYCHOLOGICAL PROBLEMS  

2

4

6

Analysis

Determine the type of problem being reported by the consumer.

 

 

 

 

Determine if the eyewear is the source of the problem reported by the consumer.

 

 

 

Solution

Communicate to the consumer the options available to correct the eyewear problems.

 

 

 

 

Perform appropriate actions to solve the problem after the consumer decides upon a plan of action.

 

 

 

 

Suggested Resources

 

Books

 

Brooks, C. F. (1983). Essentials for Ophthalmic Lens Work. Stoneham, MA: Butterworth-Heinemann.

Brooks, C. F., & Borish, I. (1986). System for Ophthalmic Dispensing. Stoneham, MA: Butterworth-Heinemann.

Stein, & Slatt. (1988). Ophthalmic Assistant: Fundamentals and Clinical Practice (5th ed.). St. Louis: Mosby.

 

Audiovisuals

 

The following title(s) format(s) are available from:

 

National Academy of Opticianry

10111 Martin Luther King, Jr. Hwy., Suite 112

Bowie, MD 20720-4299

 

Intermediate Dispensing Skills Series/VCR tapes (1989)

"Light, Nanometers, and the Spectrum," (IDS-1)

"Reflection and Refraction of Light Rays," (IDS-2)

"All About Base Curves," (IDS-3)

"Vertex Compensation in Higher Powers," (IDS-4)