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124 Cards in this Set

  • Front
  • Back
What are some of the ophthalmic regulations
• enforceable
• required by law
• FDA (impact resistant requirement)
• OSHA (Occupational Safety and Health Act)--safety in industries
• ADA (Americans with Disabilities Act)
• Food and Drug Administration, est. 1906
• Mission: promote and protect the public health
• Oversees the release of safe and effective products for consumer use in timely fashion
• Monitors products for continued safe use over time
• Regulates: food, drugs, medical devices (contact lenses), biologics, cosmetics, radiation emitting products (cell phones), animal feed and drugs
• established 1970
• Congress passed act to promote health and safety in the work force
• workplace standards set by Occupational Safety and Health Administration (Department of Labor)
• OSHA regulation 29 CFR 1910.133 re eye & face protection
– recognizes ANSI Z87.1 standards
• federal regulation, passed 1990
• protect disabled Americans
• integrate these individuals into society
• program accessibility
• avoid discrimination against individuals with disabilities in services and facilities
• establishes procedures for compliance
• disabled Americans have the same opportunities and access in the workplace, government programs, public accommodations, transportation, and telecommunications that other citizens enjoy
• equal employment opportunity
• equal physical accessibility
• Purpose – standardization/frame of reference

-dioptric reference for a given wavelength, currently the reference is the Fraunhofer helium d line (587.56nm) but European and Asian markets have desire to change it to the mercury e line (546.07)

-avoid confusion
– quality control
– public protection

-voluntary, not enforaceable/regulatory
-good practice policy
• ANSI (American National Standards Institute)
– formerly called ASA (American Standards Association)
– a not for profit institute
– not a governmental supported agency (unlike other countries)
– committees charged with task of developing standards for specific products
– committee members formed by professional organizations, trade associations, individuals (must be representative by all significant interested parties of that product)
• approximately 10 ophthalmic related standards;
revised every 5-10 years • standards recommended for "good practice"
What are the 10 ANSI standards
– Z80.1--prescription ophthalmic lenses - recommendations (2010)
– Z80.3--non prescription sunglasses & fashion eyewear requirements (2010)
– Z80.5--dress ophthalmic frames (2010)
– Z80.7--optical and physical requirements for IOL's (2002)
• Z80.9-- Ophthalmic - Low Vision Aids-
requirements (2010)
• Z80.10-Ophthalmic Instruments- Tonometers- requirements (2009)
• Z80.20-Ophthalmics-Contact Lenses-Standard Terminology Tolerances, Measurements & Physicochemical Properties (2010)
• Z87.1-- practice for occupational & educational eye & face protection (2010)
• American Society for Testing & Materials
• sets up specifications and standards relevant to materials used in industry
• has a number of sports eye protective equipment standards
What are the 8 ASTM standards
– ASTM F803-03 Eye protectors for selected sports (racket sports, women’s lacrosse, baseball)
– ASTM F513-00 (2007) Eye and face protective equipment for hockey players
– ASTM F717-89 (2006) Specification for football helmets
• ASTM F659-06 High impact resistant eye
protective devices for Alpine skiing
• ASTM F910-04 Face guards for youth baseball
• ASTM F1045-07 Standard performance specification for Ice Hockey Helmets
• ASTM F1776-10 Eye protectors for use by players of paintball sports
• ASTM F1587-99 (2005) Head and face protective equipment for ice hockey goaltenders
•International Standards Organization
– founded in 1946
– representatives from many nations
•designed to developed international standards
– no official jurisdiction, but has effect of international law
-GATT (General Agreement on Tariffs & Trade)
-United Nations members bound by GATT
•many ophthalmic standards adopted/developed by ISO, e.g.,spectacle frames, projector charts, contact lenses, lensometers, lasers, spectacle frame marking & measuring system, keratometers, phoropters, biomicroscopes, ophthalmic lens specifications, tonometers, trial case lenses, trial frames, etc.
ANSI Z80.1 (2010)
• Prescription Ophthalmic Lenses--
• scope--applicable to processing of all prescription ophthalmic spectacle lenses in edged or assembled form
• general content
– definitions, eg., add power, cylinder axis, prism, boxing system, lens clock, prism diopter, index of refraction, aspheric lens, corrective curve, multi-focal lens, laminated lens, etc.
– optical tolerances
– test methods, measuring the distance power, add power, prism power, base curve, impact resistance
What are the optical tolerances for ANSI Z80.1 (2010)
• Power tolerances apply to non-progressive lenses only
• Power tolerances is on highest power meridian
• Power: +/-0.13D up to 6.50D; +/-2% above 6.50D

• Cylinder:
+/-0.13D up to 2.00D;
+/-0.15D b/w 2-4.50D;
+/- 4% > 4.50D cylinder

• Cylinder axis
– up to 0.25D: +/-14o
– >0.25 to 0.50D: +/-7o
– >0.50 to <0.75: +/-5o
– >0.75 to <1.50: +/-3o
– >1.50: +/-2o

• Prism imbalance (mounted lenses)
– vertical: 0.33 (0 to +/- 3.375D); 1mm
variance b/w lenses if > +/-3.375D
– horizontal: 0.67 (0 to +/-2.75D); max 2.5mm variance if > +/-2.75D (for SV and non progressive multi-focal lenses) [for PALs, power limit +/-3.375D)

• IPD: +/-2.5mm

• Base Curve: +/-0.75D

• Warpage: 1D

• Center thickness: +/-0.3mm

• NIPD: +/-2.5mm

• PAL fitting cross: +/- 1.0mm of specification (horizontal and vertical)

• Segment height: +/-1.0mm of specification
• Segment size: +/-0.7mm
• Add power: +/-0.12D up to 4.00D; +/-0.18D >4D
What are the optical tolerances for PALS in ANSI Z80.1 (2010)
• Progressive Addition Lenses Power
– Tolerance on highest power meridian
– +/-0.16D up to 8.00D
– +/-2% on powers > 8.00D
– Cylinder: +/-0.16D up to 2.00D; +/-0.18D b/w 2.00 to 3.50D; > +/-5% for cyl power > 3.50D
What is the CA thickness standard?
• current ANSI standard has no thickness guideline for all lens material except glass lenses, only pass FDA’s DBT
• ANSI Z80.1--2.0mm c.t. ; 1.0mm e.t. on glass
• historical
– 1970’s--California specifies that ANSI standards in effect govern lens thickness for all lenses
– California filed for exemption to ANSI guideline; Federal gov’t in 1979-80 denied CA the exemption to the FDA thickness requirement
ANSI Z80.3 (2010)
• requirements for Nonprescription Sunglasses and Fashion Eyewear (general summary)
– light attenuation
– transmittance properties, UV, traffic signal
– flammability of fashion wear frame & lenses
– refractive power tolerance for plano lens (+1/8 diopter,
-1/4 diopter); no greater than 3/16 diopter difference
between both lenses
– astigmatic power, no greater than 1/8 diopter per lens
– prism power, no greater than 1/4 prism diopter per lens
CA DMV VC§ 23120
• “no person shall operate a vehicle while wearing glasses having a temple width of one-half inch or more if any part of such temple extends below the horizontal center of the lens so as to interfere with lateral vision.”
ANSI Z80.5 (2010)
• requirements for Ophthalmic Frames
– dress, i.e., street wear eyewear
– definitions of frame nomenclature
– lens retention by frame--lens shall not dislodged if
subjected to a minimum energy equivalent to the DBT
– frame bevel angle no greater than 110o
– not obstruct visual field
– metal frame made of corrosion resistant material
– frame flammability--will not ignite when heated for 15
minutes at 200oC
– marking & stamping of frame
ANSI Z87.1 (2010)
• relates to eyewear in occupational, educational
industrial environment
• standards for frame/face shield
• standards for lenses (high vs low impact)
• to be covered in section on industrial eyewear
Federal Trade Commission
• Purpose is to prevent deceptive market place practices
– deceptive advertising
– monopolizing
• Provide for a consumer’s opportunity to purchase eyewear other than from their prescriber; to promote competition
What is the FTC CL rule?
• The Contact Lens Rule (16C.F.R.Part315)

– Contact lens prescription must be given to the “customer” once the fitting is completed
What is the FTC Eyeglasses I rule
• The Eyeglass Rule (16C.F.R.Part456)[CodeofFederal Regulations]
• Eye care providers (ECP’s) MUST give their “customers” a copy of their prescription
– Eye glass prescription must be given to the “customer” at the conclusion of their exam
– Must be released immediately after eye exam regardless of whether requested by patient
– Even if no rx change or minimal, must give patient a
copy of rx
– Must include minimally the following: sphere, cylinder, axis, prism, prescriber’s signature
– Prohibits the use of disclaimers on prescription such as, “not responsible for accuracy of ophthalmic prescription materials not obtained in our practice”
What is the FTC Eyeglasses II rule?
– Established in 1989
– More detailed compared with Eyeglass I
– Prescription released by prescriber can include
whatever is considered pertinent for the patient’s visual welfare (does not specifically indicated components noted in previous slide)
– Permits prescriber to specify lens material, lens style, wearing instruction
– Must have an expiration date (note Eyeglass I does not specify this) [note: most State laws do not specify a requirement for an expiration date; but does not prevent a clinician from specifying one]
– As with Eyeglass I, disclaimers not permitted
California Code of Regulations
§1566 & §1566 .1
– The Consumer Notice must be posted in each optometrist’s office in a conspicuous place
– The Notice must state the legal requirements regarding release of all corrective lens prescriptions
California Business & Professions Code
• §3076--regarding patient receipt
– Other than for insurance co-payments and deductibles, must provide a receipt showing
-Patient name
-Optometrist license#
-Location of practice
-Description of all goods and services for which patient is
charged for and the amount of each
• Read ALL of California Laws & Regulations Related to the Practice of Optometry , 2011 Edition: Law Exam of California Licensure requirement
• §2541.1 Business and Professions Code Board of

-prescription release
• Patient’s name, prescription, date of issuance, expiration date, prescriber’s name, address, telephone, license #, prescriber’s signature
• Expiration date: no less than 2 to 4 years from issue date unless circumstances dictate otherwise
Expired Prescription
• May be filled in the event glasses are lost, broken, or damaged that renders the glasses unuseable AND
• Dispenser filling expired prescription informs patient to returned to provider that originally issued the Rx to have another eye exam AND
• Provide provider in writing a copy of the prescription that was filled
Double Segments structure
segment separation, usually 13.0mm
– upper add, intermediate or full add
– lower add, as specified
– available in glass & plastic
– fit lower seg 1-2 mm below limbus
– upper seg should have at least a minimum of 8- 10mm window, height measured from top of lens bevel peak to slightly above upper eyelid

-take B dimension, divide by 2, subtract 3, add the segment separation; subtract result from B dimension; result is the upper segment height. If upper segment height is less than 10mm, either drop the lower segment height or choose a frame with a larger B dimension
who are the candidates for double segments
Potential candidates include mechanics, electricians, plumbers, carpenters, librarians, dentists, pilots, surgeons
What are the availabilities of DOUBLE FLAT TOPS
DD22, DD25, DD28, DD35
– standard separation,13mm
– min separation: 11mm (22); 12mm (25); 13mm (28); 15mm (35)
– max separation: 20mm
– add availability: up to +3.00 (DD35) or +4.00
(DD25) or +5.00D (DD28)
– available with upper and lower add equal or unequal
– clear, tinted, photochromic

DD25, DD28, DD35
separation:13mm (25); 14mm (28 or 35)
-available with both upper and lower add equal or unequal
-if unequal, upper add usually +0.50D or +0.75D less plus
what are the availabilities for DOUBLE ROUND TOPS
DR22, DR25
–standard separation, 13mm
–min separation: 11mm; max separation 20mm
–add availability: up to +5.00D –available with upper and lower add equal or unequal
–clear, tinted, photochromic

DR25, DR22, DR28
–standard separation, 14mm
–usually equal upper/lower add
What is the design of the QUADRIFOCAL
– upper segment, flat top
– lower trifocal flat top
– glass only
– 7x25, 7x28, 7x35
– 13mm separation
– fit trifocal line lower pupil border
What is the design of the Executive/Flat Top?
– Sola ED or Orcolite F/D
– combination segments
– intermediate 50% or 60%
– plastic only
– limited use, but very practical lens
– fit executive line at pupil center
What are the different types of Executive/Flat Tops?
– 8 mm intermediate depth
– 50 % intermediate add power –only in +6.00 D and +8.00 D base curve
– add power from +1.50 to +3.00D

– 11 mm intermediate depth
– 60% intermediate add power – avail in +5.00 D & +7.00 D base curve
– add power from +1.50 to +3.00 D
What are the availabilities of the RIBBON occupational lens?
– Glass only
– Segment size: 9x22; 9x25; 14x22; 14x25
– Available in photochromic PGX
What is the "spot"/golfer's classic occupational lens?
15 mm round seg
-sports related or special occupational
-add available up to +30 D
What does protective eyewear need to have?
protect against
– flying particles
– molten metal
– liquid chemicals
– acids or caustic liquids
– chemical gases or vapors
– injurious light radiation
– have proper side protection

have proper prescription

comply with Z87.1 standards
OSHA 29 CFR 1910.133--(a) General Requirements.
Each affected employee shall use appropriate eye or face protection when exposed to eye or face hazards from flying particles, molten metal, liquid chemicals, acids or caustic liquids, chemical gases or vapors, or potentially injurious light radiation.
OSHA 29 CFR 1910.133--(a) General Requirements.
Each affected employee shall use eye protection that provides side protection when there is a hazard from flying objects. Detachable side protectors (e.g. clip-on or slide-on side shields) meeting the pertinent requirements of this section are acceptable.
OSHA 29 CFR 1910.133--(a) General Requirements.
Each affected employee who wears prescription lenses while engaged in operations that involve eye hazards shall wear eye protection that incorporates the prescription in its design, or shall wear eye protection that can be worn over the prescription lenses without disturbing the proper position of the prescription or the protective lenses.
OSHA 29 CFR 1910.133--(a) General Requirements.
Eye and face PPE shall be distinctly marked to facilitate identification of the manufacturer.
OSHA 29 CFR 1910.133--(a) General Requirements.
Each affected employee shall use equipment with filter lenses that have a shade number appropriate for the work being performed for protection from injurious light radiation. The following is a listing of appropriate shade numbers for various operations.
ANSI Z87.1 (2010)
lens thickness
– most prescription safety Rx: 3.0mm ct/et
– for high plus over +3.00DS, edge may be reduced to
2.5mm if it meets impact test
– plano prescription safety eyewear no less than
3.0mm thick or more than 3.8mm thick

lens impact
– 1" (2.4 ounces) steel ball dropped from 50" onto lens horizontal front surface; lens shall not break

lens retention test
– lens must not be displaced from frame
ANSI Z87.1 (2010)
Basic impact non-plano lenses
– 3.0mm thickness minimum
– Not tested to same level of impact as high impact lenses
– Lenses do not need to be marked with a “+”
– pass the industrial DBT (1” steel ball at height of 50”)
– all glass lenses are to be tested; plastic lenses batch tested
ANSI Z87.1 (2010)
High impact non-plano lenses
High impact non-plano lenses
– Lenses must not be less than 2.0mm thick
– Lenses must have the “+” mark
– to qualify for the “+” mark
-must pass a high velocity impact test: 1⁄4” steel ball shot at lens at 150 fps
-no detachment, no fracture, no displacement, no penetration
– Rx lenses are not individually tested
– Note: for plano high impact lenses, no thickness
ANSI Z87.1 (2010)
lens requirements
– a needle (135x17) must not penetrate lens surface
– prescription follows Z80.1 tolerances
– cannot mix safety lens with dress frame or vice- versa
– lens tints
-clear lenses generally recommended but tint not completely restricted
-regarded as protective filter, not cosmetic tint
ANSI Z87.1 (tinted lenses)
-if tint prescribed, must meet Z87.1 standards for minimum and maximum visible light transmittance and maximum UV and IR radiation transmittance
-tint shade number must be clearly identified !shade#: 7/3OD+1
-higher shade#: darker lenses; usually green color to filter UV/IR
-transmission between right and left lens must be within 10% of
each other

-photochromic lenses not necessarily disallowed or officially allowed; lenses must be monogrammed with letter "v"

-lenses that are tinted for special purpose situations must be monogrammed with the letter “S”
Lens markings for non plano basic impact
– w2.5

--basic impact lens made by manufacturer “w” with a lens that has a filter with shade number 2.5
lens markings for non plano high impact
– w+2.5

–high impact lens made by manufacturer “w” with a lens that has a filter with shade number 2.5
What is the occupational use of ABSORPTIVE LENSES
--designed to protect from potential chemical, mechanical and radiation damage or injury
--must absorb both UV and IR radiation
--transmit primarily in the mid-spectrum
--lenses are bluish green or greenish yellow
--level of transmittance in mid spectrum must be appropriate for task
--occupations: welders,lasers,glassblowers, blast furnace operators
ANSI Z87.1 (2010)
side shields
-side shields
– permanent
– detachable
– plastic, wire mesh, plastic mesh

-side shields required when there is hazard from flying objects

-basically all safety eyewear should have a side shield

-face shields--clear, tinted

-goggles/face masks (respirator)
ANSI Z87.1 (2010)
– musthave"lip"behindlenstopreventlens
displacement towards patient
– lenses inserted from front
– must bear Z87-2 logo (for non-plano lenses)
– Plano lenses in frame (Z87 or Z87.1)
– must have A, DBL and overall temple length identified on frame
– Z87-2 indicates frame also meets high impact testing
– meet high mass, low velocity test
--meet flammability, corrosion standard
What is the basic safety frame?
BC frames, no side shields
ANSI Z87.1 (Radiation)
--use of safety eyewear may not be the only source of protection from radiation while welding, cutting or brazing
--can use and should use safety eyewear under appropriate helmet or face-shield
--offers protection when shield or helmet is lifted up
welder’s flash (photokeratitis)
--failure to lower helmet timely at arc contact point
--immediate discomfort after flash
--stipple staining with NaF
Radiation damage from welding
--retinal burns
What are the two categories of welding lenses?
general purpose
-significant UV and IR reduction

specific for reduction of sodium D-line radiance (589.3nm)
--similar to Class I lenses but in addition reduces transmittance at 589 nm with addition of didymium
Welding lens transmission: SHADE NUMBER
Shade number is usually 1.5 to 14

higher shade number-->darker the lens or less transmission
-greenish blue or rose brown color
-dichroic--exhibiting different colors under various light sources
– incandescent--rose color
– fluorescent--greenish blue
-cerium oxide with didymium
-designed primarily for glass blowers to filter out the Na+ light
-filters out the yellow flame (Sodium Flare)
-absorbs in the 570-590 nm range; primarily an occupational lens
-only available in one piece multifocal lenses
What are some recommendations for welding lenses
– electric arc welding: shade #’s 10-14
– gas welding: shade #”s 10-12 heavy welding, #5 for lighter
–brazing--#3 or 4
– soldering--#2
–[general sunwear 1.5 to 2]
What are some protective device options
--safety spectacles
--chipping goggles
--impact or dust goggles
– soft, flexible plastic material
– lenses, polycarbonate
– wear over glasses
--chemical goggles
– similar to impact/dust goggles except different
ventilation system
--plastic face shield
– protect head, neck, face & eyes from flying debris, chemical or molten metal splash
What are the musts in eye protection?
--Protect against the specific hazards encountered in
the workplace (see Guide for the Employer).
--Be reasonably comfortable to wear.
--Not restrict vision or movement.
--Be durable and easy to clean and disinfect.
--Not interfere with the function of other required
--PPE (such as respirators).
• goal: improve visual fitness--enhance sports performance
• visual acuity
• eye-hand coordination
• depth perception
• visual attention-reaction time • peripheral vision
• therapy: spectacles, contact lenses, refractive surgery, visual training, etc.
• protection: impact resistant
• visual acuity
• contrast enhancement
• radiation (UV) filtration
– dust, sun, wind
– pinguecula, pterygium, photokeratitis, cataract
• peripheral vision
• glare •
minimal color distortion
Sports wear FRAMES
• fully cover orbital region
• proper contact at bridge & temples
• beveled so that lens expulsion is not towards the eye
• fit properly
• follow ASTM (American Society for Testing & Materials) standards
ASTM F803-03
american society for testing and materials
• 4 major types of eye protection devices
– face masks & shields (catcher’s masks or football helmet) [Type I]
 full face
 varying size openings
 shields made of polycarbonate
 bulky, uncomfortable, difficult to hold in place

– lensless eyeguard with a narrow opening [Type II]
 no longer proven safe for racquetball
 racketball/squashball may deform and penetrate opening

• bubble lens with uniform frame construction [Type III]
– very curved lens, distortion
– lens and frame front piece molded as one unit
– not available in prescription form

• eyeguards with lenses [Type IV]
– polycarbonate lens and frame
– frame with no hinges, sports strap
– most widely used today, e.g., Liberty RecSpecs, Bolle)
Sports Safety LENSES
• polycarbonate
– superior to all lens materials
– large or small objects
– high or low velocity objects
• UV protection
• proper absorptive tint color & level of absorption
• Multiple sports consideration -switching of lenses
•water sports
– frame: Aqua-See, Barracuda
– lenses: polarizing, UV protection
–swim googles: curvature of lens? [vision under water]

• skiing
– lenses: UV protection, polycarbonate, polarizing

• scuba-diving
– lenses: bonded to face plate of diving masks
–use glass lenses; front surface plano; power on back surface
–adjust power for vertex distance

•court related sports
– lenses: polycarbonate, UV protection
–goggle type frames with sports strap

• cycling
– lenses: polycarbonate, UV protection
–wrap around style to keep out the wind and debris
• Conventional
– Default facial wrap angle, typically 10 degree
– Pantoscopic tilt, typically 10-12 degree
– Base curve of demo lens, typically +6.00D
– Vertex distance 13.5mm

• Wrap
– Default facial wrap angle, usually averages 20 degree
– Pantoscopic tilt, may be greater than 12 degree
– Base curve of demo lens, typically +8.00D
– Vertex distance, 12.5mm or less
– Must have optimum fit at time of frame selection
• Corrective curve lenses
• Compromises
• Consequences
– Lens fit in frame
– Visual performance
– Magnification differences, vertex distance
– Peripheral vision
– Difficult adaptation
• Lenses are made on an +8.00D base
– A corrective curve for a restricted number of rx’s (approx 8%)
– Majority rx’s outside of the +8.00D BC (about 92%)
– Rx needs to be compensated
– Recommended prescription range: +2.00D to -5.00D
• Prism induced, binocularity affected
– Base out, requires BIn to offset
Prismatic Effect
• Prismatic effect, function of – Angle of tilt
– Base curve
– Lens material index
– Lens thickness

• Magnitude of prism
– prism=100tan(theta)(t/n)P1
Plantiff must prove the following for negligence
– duty to provide due care
 follow conduct to minimize harm to patient
– breach of standard of care
 act prudently and use reasonable skill and knowledge
– injury (presence)
– proximate cause
 the primary cause of the injury (if it were not for the cause, injury would not have occur)
 failure to prescribe lens material of choice
 failure to warn of the risk of injury from alternative lens
 failure to recommend the most impact resistant lens material (polycarbonate and/or Trivex)materials
 failure to inspect and verify lens order
 practitioner obligated to explain differences in various lens materials
 patient acknowledges that he has been informed, elects to choose a different material
 patient signs informed consent
– informed of warning
– aware of reduced impact resistance
– voluntarily chooses less impact resistant material
– keep in patient’s file forever
 legal obligation to inspect ophthalmic lab orders
– correct prescription, meeting ANSI Z80.1 standards
– correct lens material
– correct coating
– correct tint
– check lens surface, lens bevel, lens edges
– properly mounted
– proper frame, specifications
 sue for negligence as related to frames
 idiosyncratic responses
– allergic reaction
– poor adjustment, break in skin
 improper safety frame
– do not mix safety frame with dress safety lenses or vice versa (Z87.1)
 improper sports frame
– use frames as recommended by ASTM for given sport (ASTM F803)
 introduced by OLA (1987)
 practitioner must properly inform patient of different lens choices
 all dispensed eyewear must be accompanied by a “Eyeglass Safety Warning”
 not the law
 negligence issue
 product liability--strict liability or absolute liability; representing product as causing no harm
 burden of defective product on producer
 manufacturer is liable as a matter of law whenever a consumer is injured due to a defect in the product
 often difficult to prove injury result of product
 submit evidence
 expert testimony
 some standard to base judgment
– ANSI Z80.1, Z80.3, Z80.5, Z87.1
– ASTM F803
alleges that defect in lens or frame resulted in the dangerous use of the product for the intended purpose and hence the injury
– not in compliance with ANSI  defective design, e.g., poor laboratory workmanship
 defective warnings or directions: advise patient of
the appropriate use of eyewear and when inappropriate
 defective inspection: order must be as prescribed
What are some of the asthenopia complaints from VDT users?
eyestrain (eyes tense)
eye fatigue (eyes heavy)
sore eyes (eyes tender, achy)
What are some of the visual complaints from VDT users?
blurred vision (distance/near)
double vision
focus adjustment
oblique fixation
color perception disturbance
color around newsprint/books
What are some ocular complaints from VDT users?
-dry eyes
-watery eyes
-irritated eyes
-red eyes
-contact lens discomfort
What are some musculo-skeletal complaints from VDT users?
neck ache
back ache
shoulder ache
wrist or hand ache
What are some visual contributors to the eye problems in VDT users?
refractive error, BV, accommodation, dry eyes, spectacle lens design.
Cumulative Trauma Disorders (CTD)
Cumulative Trauma Disorders is any physical disorder that develops from or is aggravated by the cumulative application of biomechanical stressors to tissue and joints, including but not limited to bursitis, ligament strains, muscle strains (e.g., neck-tension syndrome), nerve entrapment (e.g., carpel tunnel syndrome), stenosing tenosynovitis (e.g. de Quervain’s syndrome and trigger finger/thumb) and hand-arm vibration syndrome
Repetitive Motion or Strain Injury
RSI is a soft tissue injury in which muscles, nerves, or
tendons become irritated or inflamed. It is caused by repetitive motions, excessive force, and extremes of motion. Over time these motions can strain the soft tissues, reducing circulation. These stresses create tiny tears in the muscles and tendons, which become inflamed. In extreme cases, it can cause permanent tissue damage and disability.
What are the SIGNS of Cumulative Trauma Disorder (CTD)
-change in skin color
-decrease range of joint motion (tightness, discomfort, soreness or burning in the hands, wrists, fingers, forearms or elbows)
-decrease grip strength
-swelling of joint
-swelling of part of arm, leg or finger
What are the SYMPTOMs of Cumulative Trauma Disorder (CTD)
-pain from movement
-pain from pressure
-pain from exposure to cold or vibration
-numbness or tingling in arm, leg or finger
-clumsiness or loss of strength and coordination in the hands
-pain that wakes you up at night
the scientific study of the relationship between people and the design of work
How do you reduce glare discomfort for VDT users?
--reduce fluorescent lighting
--modify louvers, use parabolic --change work station orientation
--wear a visor
--surroundings, avoid reflective surfaces
--window coverings, drapes/blinds
--auxiliary lighting
--screen brightness
How do you make better lighting for VDT users?
--typical office fluorescent lighting more than necessary for computer use (approx. 4X more)
--filter over fluorescent tubes decrease illumination levels
--acrylic PMMA panels tinted
--results: decrease frequency of eyestrain, eye fatigue,
light sensitivity, less glare or reflections from VDT screen; no noticeable difference in burning, itching, pain, headaches or personal energy levels; 74.5% preferred filtered to unfiltered light (study: SCCO, J. LaMotte, OD)
Where do you position the monitor to make it more comfortable for VDT users?
below eye level, top of monitor tilted 10-20 degrees away

top of monitor 4”-8” below eyes (primary gaze)

distance approx. 20”-28” or 50-70 cm away

location: either screen or document oriented

monitor located at right angle to window
What is the effect of the monitor output?
accommodative system response
-accommodative lag
-RPA (resting point of accommodation)
What is the appropriate workstation for a VDT?
work surface
-approx. 26” height
-ideally an adjustable desk, bi-level
-desk w/o center drawer
-non reflective surface, matte preferred
-non white surface -
orientation perpendicular to light direction
What is the proper chair adjustment at a VDT?
chair adjustment
-back support, part of weight to back of spine (110 degree)
-feet flat on floor or on angled foot rest
-knees bent at or about 90 degrees
-seat provide support of thighs, 2 to 4” hollow
-thigh to trunk angle, about 90 degrees or greater
-elbow angle about 90 degrees or greater
What is the proper chair at a workstation?
backrest--support lower and upper back; slightly curved; adjustable

armrests--optional, but should support forearm, relaxing shoulders; proper height & width of armrests important

seat--properly padded and wide enough for full support of thighs; adjustable

seat--front of chair rounded

chair base--5 casters, adequate width to avoid tipping over
What's the 20/20/20 Rule?
Every 20 minutes take a 20 second break at 20 feet away
Dynamic Power
from near to VDT monitor--optimal 0.75 D to 1.25 D

beyond VDT monitor--greater than 1.25 D dynamic power
For non-presbyope with significant near tasks
+0.60 additional plus power, lower part of lens
-power progression over approx 8mm corridor
Fitting: D mono PD, Fitting height at pupil center (min 13), provide lab with D Rx

Materials: CR-39, Polycarb, 1.67

Verification: same as single vision lens
-emphasizes intermediate zone of PAL
-Approx 50% ad power at intermediate
-Full distance, intermediate, near Rx
-Full distance Rx at 14 mm above fitting cross
-Full near Rx at 14 mm below fitting cross
-provide lab with full near and dynamic power (add range +1 to +3.5)
-monocular distance PD
-Fitting height at pupil center (15 minimum)
-B frame minimum: 30 mm
-Verify total near Rx in reading area (at least 15 mm below the fitting cross)
-Polycarb only: -6 to +7, cyl to -4.00D
-temporal side: add power; nasal side: essilor Logo with "P"
occupational lens
expand SV range
+0.75 or +1.25 power progression
+0.75 for add powers up to +1.50
+1.25 for add powers greater than +1.50
corridor, 10mm
fit frame with pupil 5mm above 180 line or take vertical ht
measurement and subtract 5mm (must have minimum 15mm)
order with full near Rx (rx calculated for near)
identify +0.75D or +1.25D progression
give near PD
CR-39 & polycarbonate (AC or AP), no right & left lens
Access HD (1.67) [Europe/Australia]
Sola Continuum--+1.00 progression (retails)
--occupational lens
--expand SV range
--distance is increase by +0.50D
--add power 0.50D less
--recommended height, 25mm --order full distance & add, lab adjusts power
--CR-39 & hi-index glass
--occupational lens
--expand SV range
--+0.75, +1.25, +1.75 or +2.25 dynamic powers
--full near less 50% of dynamic power at fitting cross
--corridor length: 25mm
--increasing plus 13mm down from fitting cross
--decreasing plus 12mm up from fitting cross to top power
--dynamic power, +0.75D: add <+1.50
--dynamic power, +1.25: add+1.50 to +1.75
--dynamic power, +1.75D: add>+2.00
--dynamic power, +2.25: add>+2.50
--fitting cross at pupil center; mono distance PD
--frame: mini 13 mm from pupil center to top rim; 16 mm from pupil center to lower rim
--order distance Rx w/ add; specify dynamic power
--verification at NRP
-CR-39 only; Base Curve: +5.00D, +7.00D
+1.00, +1.50 dynamic power
50% of dynamic power at fitting cross
-12 mm from fitting cross to top of near power
-15 mm from fitting cross to center of near power
-12 mm up from fitting cross to intermediate power
-24 mm corridor
-measure from pupil center down: min 16 mm down from fit cross, min 14 mm up from fit cross, B frame min 30 mm
-distance monocular PD

ZEISS BUSINESS 10-displays a power decrease of 1.00 D
-Recommend use for add powers up to 1.75 D

ZEISS BUSINESS 15-displays power decrease 1.50D
-Recommend use for add powers 2.00 D and up
-occupational PAL
-distance Rx present
-corridor length: 23.5 mm
-10mm to distance Rx from cross
-13.5 mm down to top of add from cross
-2 fitting options at cross: EP40--40% of add, EP60--60% of add

Fitting: mono dist PD; vertical fitting height, rec min 18 mm
-select fitting position
-order distance Rx w/ add
-verify like general PAL
-CR-39 only
-T1: temporal engraving ; add nasal
-R and L blanks; multiple Base Curves

-release in US market soon
-similar in concept to Essilor Anti-Fatigue lens
-Updated lens surface aspherization
-two options: sync 5 (+0.55D), sync 8 (+0.88D)
-fitting: mono dis PD's, dist Rx, vertical OC fitting height, mini fitting height >11 mm
-verification: separate R and L lens, locate markings like PAl, dist power, Prism reference point, near reference point
Rodenstock Cosmolit Office
-occupational lens
-expand SV range
-corridor length, 28 mm
-dynamic powers: 1.00 or 1.75 D
-lens OC4 mm below fitting cross
-5 base curves, CR39 only

Cosmolit Office 100
-total power change of 1.00 D
-recommend for wearers with add powers from 1.00D to 1.75 D

Cosmolit Office 175
-total power change of 1.75 D
-recommend for wearers with add powers from 2.00D to 3.50 D
Rodenstock Office Fit

distance mono PD
-vertical fitting height to cross, minimum 20 mm
-order dist Rx w/ add
-R and L lens, 1.0mm inset
-verify at 4 mm below fitting cross
Tints and Coatings with VDT
--questionable value
--pink might be some comfort, especially in offices with
fluorescent lighting: attenuates blue light emission from tubes, hence decreasing brightness and fluorescence within eye
--VDT tints: lot of hype

UV Tx: no evidence of harmful UV emission from monitors

ARC coating
VDT lenses with distance Rx
ESSILOR COMPUTER LENS: 50% of prescribed add power in primary gaze

VDT lenses with 50% dynamic in primary gaze


SHAMIR OFFICE 0.75, 1.25, 1.75, 2.25

rodenstock cosmolit office
How to figure out which lens to use.
1. Identify monitor distance
2. range of clear vision desired
3. lower vs. higher dynamic power
4. lens corridor length
5. need distance vision?
essilor computer lens
hoya tact
gradual RD
other uses of VDT lenses outside of computer use
-CL wearer
-post refractive surgery
-intermediate/near recreational/hobby
Gunner lenses
advanced computer eye wear

advanced gaming eyewear

premium 3D eyewear

advanced outdoor eyewear
What are some visual factors in motor vehicle driving
Burg Study
weak correlation between visual factors and driving performance

accidents correlate with VA for older people, over the age of 54

DVA greater correlation than static VA but no accepted standard for DVA and DVA no repeatable
Hofstetter Study
individuals with poorer acuity were twice as likely to have 3 ACCIDENTS in past 12 MONTHS compared with population with better acuity.

-correlation of VA and driving performance
Other VA and Driving Studies
high contrast visual acuity testing vs. contrast sensitivity

the parameters were different
low contrast visual acuity test would have been a better test
Visual Fields and driving?
 Is there a relationship between detection and identification of objects in peripheral field with driving performance?
 many studies--no correlation between VF measurements & driving performance
 Johnson/Keltner Study: 10,000 drivers
– binocular VF loss had accident and traffic violation rates 2x greater than drivers with normal visual fields
– drivers with monocular field loss ONLY, not significantly different from normals
– tested between 50-60 degrees of central fixation, automated screener.
Monocularity and driving?
no big!

 monocular individuals are at greater risk for accidents and poor driving behavior
 stereopsis test results not correlated with accident rates
 CA DMV--automatic failure unless proof of longstanding
Color vision and driving?
 protanopes & deuteranopes expected to confuse red, yellow, green
 greater risk for accident?
 green signal standardized to a bluish green, so dichromats able to distinguish between it and red and yellow
 protanopes: not proven to have more problem with red signal, brake or tail lights
 generally, color vision defects not associated with higher accident rates
Mature driver--Accidents
25% of driving population are age 55 & greater
 responsible for
18% of all accidents
 elderly have FEWER accidents, BUT rate of accident per mile driven is relatively HIGH
 elderly drive less total miles each year
 accidents caused by elderly generally more fatal
 accident rate lowest among 35-54, worse between 18-34
Driving standard
 VEHICLE CODE § 12804.9.3:
– “any physical defect of the applicant, which, in the opinion of the department, is compensated for to ensure safe driving ability, shall not prevent the issuance of a license to the applicant”
General driver's license visual requirements.
 most states BVA OU standard
– typically 20/30 to 20/60
– 20/40 most common [CA 20/40]
 some states VF requirement
– between 70 to 140 degrees
 visual screening failed
– the individual will usually meet the standards with their
spectacle correction
– required to wear correction for driving
 visual screening required by most states for licensure renewal
What is considered legally blind?
 visual acuity
– best corrected visual acuity is 20/200 or worse
in the best eye

 visual field
– field is limited to 10o or less
CA DMV vision standards
 Snellen equivalent:
20/40 OU and 20/40 minimum in one eye and 20/70 minimum in other eye (Class C vehicles)

 fail 20/40--Optec 1000 device
– target 1 through 6 (1: 20/200; 2: 20/100; 3:
20/67; 4: 20/50; 5: 20/40; 6: 20/33)
– referral failure

 Minimum visual acuity: 20/200 in at least one eye