Opthalmic Optics Quiz - Final

Which statement is false

• A.

  UV absorption is different than a tint

• B.

  Tint refers to merely the the color of the lens

• C.

  UV protection is necessary b/c much of the light in the UV and IR regions of the spectrum that strikes the eye will reach the retina

• D.

  Transmission is the mount of light that passes through a lens

• E.

  Glass, sand, snow, pavement and metal are all good polarizers of light by reflection

Select the False statement regarding glass photochromic lenses

• A.

  Photochromic lenses can also be referred to as variable tint lenses

• B.

  A photochromic lens will change its transmission when exposed to light

• C.

  When glass photochromic lenses are activated by UV the silver and halogen combine to form silver halide

• D.

  Response and recovery time for glass photochromic lenses is dependent on the glass material

Select the True statement regarding plastic phoochromic lenses: A. When activated the molecule indolino spirorazines (ISN) ruptures and changes structure B. After the ISN changes the lenses will lighten to increase transmittance C. They are only available in tint and gray

• A.

  A

• B.

  B

• C.

  C

• D.

  All of the above

• E.

  A and C

All of the following are effects of Infrared Radiation except: A. Absorption of high energy IR radiation causes vibrational changes in molecules B. Decreased temperature on tissue causes denaturation of proteins C. Coagualtion and opacification in the cornea and depigmentation and atrophy in the iris D. Photokeratitis and pterygia

• A.

  A

• B.

  B

• C.

  C

• D.

  A and C

• E.

  B and D

Regarding ANSI Z80.3 sunglass labeling: Which of the following is not paired properly A. Cosmetic : block 50% UV-B and 50% UV-A B. General Purpose: blocks at least 95% UV-B and 60% UV-A C. Special Purpose: blocks at least 99% UV-B and 60% UV-A

• A.

  A

• B.

  B

• C.

  C

• D.

  A and B

• E.

  B and C

Complete the statement: Anti-reflective Coatings...

• A.

  Are a number of thin optical coatings applied to one side of the lens to reduce reflections

• B.

  Result in reduced reflections that increase light transmission through the lens

• C.

  Eliminate the specularly reflected light and improves visual acuity

• D.

  Reflect light that will be perpendicular to the plane of incident light

• E.

  Correct increased retinal contrast

Select the FALSE statement

• A.

  Chemically tempered glass are more impact resistant than CR-39 against large slow moving objects such as a softball but CR-39 is more impact resistant against small high velocity objects

• B.

  Benefits of Trivex include easier tinting, and less chromatic aberration. Trivex is also the lens of choice for drill mounted lenses.

• C.

  By law, all eyeglass and sunglass lenses must be impact resistant EXCEPT when such a lens will not otherwise fulfill the patient’s visual requirements

• D.

  Anyone edging, coating or tinting a lens is considered a “manufacturer” of the lens and can be held liable for the impact resistance of that lens

• E.

  Plastic lenses must be heat treated and treated with a chemical bath in order to become impact resistant.

Veiling glare is described as a reduction of the resolution of an image, a decrease in contrast of the retinal image.

• A.

  True

• B.

  False

Select the FALSE statement:

• A.

  Chemical tempering can only be done on Crown or high index glass

• B.

  Chemical tempering creates more impact resistance than thermal tempering

• C.

  Air/Thermal tempering can be done on all materials

• D.

  During thermal/air tempering the lenses are heated to 650C and then rapidly cooled, producing surface compression and internal tension

• E.

  Chemical tempering takes longer than Air/thermal tempering and the end product is not as impact resistant as the end product of chemical tempering

All lenses must be tested for impact resistance with the exception of lenses such as laminated glass, nonprescription (OTC) lenses, raised edge multifocal lenses( executive BF). These lenses can be tested via statistical sampling from each production batch.

• A.

  True

• B.

  False

Select the TRUE statements A. The drop ball test is performed on glass and plastic after edging and hardening and before it is placed in a frame  B.  Batch testing is normally done on plastic lenses and nonpresciption lenses. If the lenses are altered i.e. by AR coatings then the lenses must be retested. C. Dress lenses have a minimum thickness requirement and must meet impact resistance requirements D. There are two categories of safety eyewear: basic impact and high impact resistance

• A.

  A

• B.

  B

• C.

  C

• D.

  D

• E.

  All of the above

• F.

  B and D

Select the false statements regarding basic and high impact lenses A. Both lenses must withstand the high velocity impact test: 1/4 inch steel ball traveling at 150ft/sec B. Basic impact lenses must have a warning stating that they meet BASIC impact standards only C. Both high and basic impact lenses bear the manufacturer's marking, however only high impact lenses have a plus sign after the trademark. D. High impact lenses must be a minimum of 3.0mm thick

• A.

  A

• B.

  B

• C.

  C

• D.

  D

• E.

  A and D

• F.

  A, C and D

Scratches on the front and back of glass and plastic lenses reduce impact resistance by equal amounts.

• A.

  True

• B.

  False

Select the True statement

• A.

  AR coatings and scratch resistance coatings will increase impact resistance

• B.

  AR coatings and and scratch resistance coatings absorb the impact energy and increase resistance in plastic

• C.

  Without a coating, plastic will not flex on impact

• D.

  Glass is weakend more my scratching than CR-39

Who is not considered a high risk individual?

• A.

  Monocular individuals

• B.

  Athletes

• C.

  Children

• D.

  Low myopes

• E.

  Machine operators and plumbers

Which statement is false?

• A.

  The spectacle frame test evaluates the strength of the temples and side shields. It requires that the frame or lenses much not come into contact with the eye

• B.

  The purpose of the high velosity impact test is to proive that a frame can withstand the impact of small objects traveling at high speeds.

• C.

  In order to pass the high velocity impact test no frame or lens breakages may result, and the lens can't come out of the frame

• D.

  The high mass impact test is done the same way as the the high velocity impact test

Lateral protection must be ___ mm behind the corneal vertex.

Which of the following is not a safety frame marking requirement?

• A.

  "B" dimension

• B.

  DBL

• C.

  Manufacturer's identifying trademarks

• D.

  "Z87" for 3.0mm thickness lenses - basic impact lenses

• E.

  "A" dimension

Select the FALSE statement

• A.

  There are 2 classes of multifocal lenses: segmented multifocals and progressive addition lenses (PALs)

• B.

  As the patient's add power increases the near working distance increases

• C.

  If you prescribe according the patient's age you would start off my giving a 40 year old b/t 1.00-1.75 Add

• D.

  According to Dr. Y by 60's and older you would be giving your patient 3.00D add/Absolute add

Which statement is false? A. In a fused multifocal the segment has a lower index of refraction than that of the distance carrier B. Custom made lenses that have a small seg glued to the distance lens are referred to as Cement lenses C. In one piece multifocals the change in power in the seg is due to a change in surface curvature of the lens D. In a one piece multifocal the seg can be felt and in a fused multifocal the segment cannot be felt because it is fused into the distance portion

• A.

  A

• B.

  B

• C.

  C

• D.

  D

For lenses made with indexes of refraction greater than crown glass, the lens clock will _________ (overestimate or understimate) the true lens power and for those lenses with indexes of refraction less than crown glass the lens clock will ______(overestimate or underestimate) the true lens power

Which of the following is the optical performace of bifocals not dependent on?

• A.

  Image jump at the seg top

• B.

  Image jump at the reading level

• C.

  Overall lens thickness

• D.

  Chromatic aberration

• E.

  Total displacement at the reading level

The linear field of fixation through a segment increases as the segment diameter and viewing distance ______(increases or decreases)  and as the vertex distance  _____ (increases or decreases).

Which statement is FALSE:

• A.

  If the prismatic power of the distance portion differes from the prismatic effect of the seg, the images "jumps"

• B.

  The image jump decreases the farther the segment OC is away from the top of the segment line

• C.

  Image jump results from the vertical prismatic effect at the line b/t the carrier lens and the segment

• D.

  The differential displacement of light at the top of a seg results in an apparent scotoma

• E.

  Image displacement through a seg occursif the reading level is NOT coincident with the seg OC

If the reading level is below the OC  ____  (BI, BD,BU, BO) is induced. If the reading level is above the OC ____  (BI, BD, BU, BO) is induced.